The distribution of GABA-like immunoreactivity in the thoracic nervous system of the locust Schistocerca gregaria

Summary An antiserum raised against gamma aminobuyric acid (GABA) was used to stain the thoracic nervous system of the locust. It stained both neuronal somata and processes within the neuropile. Among the stained somata, those of the three pairs of common inhibitory motor neurones could be identified in each of the three thoracic ganglia. In the pro- and mesothoracic ganglia five discrete groups of somata are stained, four ventral and one dorsal. In the metathoracic neuromere, an additional second dorsal group can be identified. In the abdominal neuromeres of the metathoracic ganglion both dorsal and ventral somata are stained but the latter cannot be divided into discrete populations. In each ganglion, dorsal commissures (DC) IV and V are composed of stained neurites, DCVII, the supramedian commissure, the perpendicular tract, and all the longitudinal tracts contain both stained and unstained neurites. DCI, II, III and VI, the T and I tracts are unstained. An abundance of GABA-like immunoreactive processes is found throughout the neuropile except for the anterior ventral association centre where stained processes are sparser. Some of the stained cell groups contain neurones that have been studied physiologically. The function of these neurones is discussed.Beit Memorial Fellow     

GABA-like immunoreactivity in the suboesophageal ganglion of the locust Schistocerca gregaria

Summary Neurones in the suboesophageal ganglion of the locust Schistocerca gregaria were stained with an antiserum raised against gamma amino butyric acid (GABA). This ganglion consists of the fused mandibular, maxillary and labial neuromeres. Immunoreactive cell bodies of similar size and distribution occur in the lateral, ventral and middorsal regions of all three neuromeres. Approximately 200 cell bodies stain in both the mandibular and maxillary neuromeres and 270 in the labial neuromere. A few distinctly larger cells occur in the ventral groups and one large pair occurs in the lateral group of the maxillary neuromere. Dorsal commissures DCIV and DCV are composed mainly of stained fibres, while DCI–DCIII are largely unstained. A ventral commissure also stains in the maxillary neuromere. All longitudinal tracts contain both stained and unstained fibres. Many processes within the neuropil are also immunoreactive. A stained axon is found in the posterior tritocerebral commissure which enters the anterior dorsal region of the mandibular neuromere. The salivary branch of the 7th nerve contains one stained axon and two axons stain in nerve 8 which innervates neck muscles.     

Neuroanatomy of the terminal (sixth abdominal) ganglion of the crayfish,Procambarus clarkii (Girard)

Summary We studied the neuroanatomy of the terminal (sixth abdominal) ganglion in the crayfish Procambarus clarkii with silver-impregnated sections and nickel fills. We describe the fiber tracts, commissures and neuropilar areas, and give the topological relationships of motoneurons and intersegmental interneurons with reference to their neuropilar landmark structures.All five anterior abdominal ganglia have an almost identical number of 600–700 neurons with a similar pattern of distribution. Each contains a single neuromere with a common plan of neuropil organization. In contrast, the terminal ganglion consists of two neuromeres which appear to be derived from the intrinsic sixth abdominal and telson ganglion. The basic organization of each neuromere parallels that of the third abdominal ganglion in the appearance and arrangement of fiber tracts and commissures, although some modifications occur. The fusion of two neuromeres is represented by the duplication of segmentally homologous neurons, MoGs and LGs, whose topological relationships to the neuropil structures are similar to those of the anterior ganglion.We also discuss the origin of the telson and its ganglion (the seventh abdominal neuromere), and dispute the classical theory that the telson derives from a postsegmental region.     

The distribution of glutamate-like immunoreactivity in the thoracic and abdominal ganglia of the locust (Schistocerca gregaria)

The distribution of glutamate-like immunore-activity in the thoracic and abdominal ganglia of the locust was studied using two polyclonal antibodies against glutamate. Because glutamate is a precursor of the inhibitory transmitter -amino butyric acid (GABA) the distribution of immunostaining by antibodies against glutamate and GABA was closely compared in adjacent serial sections. When the antibodies were used at optimal dilutions there was no overlap in the distribution of immunostaining for glutamate and GABA. In the pro- and mesothoracic ganglia 360–400 somata are immunoreactive for glutamate, while in the metathoracic ganglion about 600 somata were stained. These range in diameter from 10–100 m in diameter and include the majority of the large somata in these ganglia. Bundles of primary neurites emerging from these large somata can be traced through the neuropile. Most of the bundles correspond to the known paths of motor neurone primary neurites. In addition the T-tract is also immunolabelled. The free abdominal ganglia each contain 80–100 somata ranging in size from 10–45 m while the terminal ganglion contains about 250 somata, 10–60 m in diameter.     

绿盲蝽腹神经节的解剖结构

【目的】揭示绿盲蝽Apolygus lucorum腹神经节的组成结构。【方法】采用免疫组织化学染色方法,利用突触蛋白抗体对绿盲蝽成虫的腹神经节进行免疫标记,激光共聚焦扫描显微镜扫描照相获得原始数据,用图像分析软件进行标记,构建三维结构模型。【结果】绿盲蝽成虫腹神经节位于腹神经索的末端,与其前方的后胸神经节和中胸神经节紧密融合,形成后部神经节。与脑和胸神经节类似,腹神经节由周围的细胞体和内部的神经髓构成。腹神经节的神经纤维束主要包括位于腹侧的两条纵向神经连索和向两侧发出的9束神经纤维。9束神经纤维连接着9个神经原节,即富含突触联系的神经髓。这些神经原节紧密融合,无明显的边界,最后两节形成膨大的末端腹神经节。两侧的神经原节由横向的神经连锁连接起来。腹神经节外周的细胞体数量较多,排列紧密,大小一致,仅在前端背侧中间和后端腹侧中间位置分别有2个和5个体积较大的细胞体。【结论】本研究结果明确了绿盲蝽腹神经节的结构,为进一步研究昆虫的行为调控及神经系统发育和演化奠定一定的形态学基础。     

The distribution of pheromone-biosynthesis-activating neuropeptide (PBAN) immunoreactivity in the central nervous system of the corn earworm moth,Helicoverpa zea

Summary Production of sex pheromone in several species of moths has been shown to be under the control of a neuropeptide termed pheromone-biosynthesis-activating neuropeptide (PBAN). We have produced an antiserum to PBAN from Helicoverpa zea (Lepidoptera: Noctuidae) and used it to investigate the distribution of immunoreactive peptide in the brain-suboesophageal ganglion complex and its associated neurohemal structures, and the segmental ganglia of the ventral nerve cord. Immunocytochemical methods reveal three clusters of cells along the ventral midline in the suboesophageal ganglion (SOG), one cluster each in the presumptive mandibular (4 cells), maxillary (12–14 cells), and labial neuromeres (4 cells). The proximal neurites of these cells are similar in their dorsal and lateral patterns of projection, indicating a serial homology among the three clusters. Members of the mandibular and maxillary clusters have axons projecting into the maxillary nerve, while two additional pairs of axons from the maxillary cluster project into the ventral nerve cord. Members of the labial cluster project to the retrocerebral complex (corpora cardiaca and cephalic aorta) via the nervus corpus cardiaci III (NCC III). The axons projecting into the ventral nerve cord appear to arborize principally in the dorsolateral region of each segmental ganglion; the terminal abdominal ganglion is distinct in containing an additional ventromedial arborization in the posterior third of the ganglion. Quantification of the extractable immunoreactive peptide in the retrocerebral complex by ELISA indicates that PBAN is gradually depleted during the scotophase, then restored to maximal levels in the photophase. Taken together, our findings provide anatomical evidence for both neurohormonal release of PBAN as well as axonal transport via the ventral nerve cord to release sites within the segmental ganglia.Abbreviations A aorta - Br-SOG brain-suboesophageal ganglion complex - CC corpus cardiacum - PBS phosphate-buffered saline - PLI PBAN-like immunoreactivity - TAG terminal abdominal ganglion - VNC ventral nerve cord     

Functional and morphological evidence for the existence of neurites from abdominal ganglion bag cell neurons in the head-ring ganglia of Aplysia

Summary Three lines of evidence are presented indicating that axons of the Aplysia neuroendocrine bag cells extend into the head-ring ganglia of the CNS. When the abdominal ganglion was bisected longitudinally, separating the two bag cell clusters, an afterdischarge induced in one cluster generated an afterdischarge in the other via activity through the head-ring ganglia to which each half abdominal ganglion was attached by connective nerves. This suggests that some axons of bag cells in each cluster communicate through the head-ring ganglia. Retrograde labelling of bag cells occurred when rhodamine-onjugated latex microspheres were injected into the cerebral or either pleural ganglion, a direct demonstration that bag cell axons extend into these ganglia. Finally, cell LP1 in the left pleural ganglion was inhibited during a bag cell afterdischarge, an action mimicked by application of alpha-bag cell peptide (BCP). Since BCP can act only close to its site of release due to susceptibility to peptidase activity, it is likely that LP1 inhibition is dependent on the local release of BCP from bag cell neurites in the pleural ganglion. These results open new possibilities for how bag cell afterdischarges may be initiated and broaden the distribution of their effects.Abbreviations ASW artificial sea water; -BCP -bag cell peptide - ELH egg-laying-hormone - IR immunorective - PB phosphate buffer - PVC pleurovisceral connective     

CNS microstructure in the wandering wolf spider Arctosa kwangreungensis (Araneae: Lycosidae)

The supraesophageal ganglion of the wolf spider Arctosa kwangreungensis is made up of a protocerebral and tritocerebral ganglion, whereas the subesophageal ganglionic mass is composed of a single pair of pedipalpal ganglia, four pairs of appendage ganglia, and a fused mass of abdominal neuromeres. In the supraesophageal ganglion, complex neuropile masses are located in the protocerebrum which include optic ganglia, the mushroom bodies, and the central body. Characteristically, the only nerves arising from the protocerebrum are the optic nerves, and the neuropiles of the principal eyes are the most thick and abundant in this wandering spider. The central body which is recognized as an important association center is isolated at the posterior of the protocerebrum and appears as a complex of highly condensed neurons. These cells give off fine parallel bundles of axons arranged in the mushroom bodies. The subesophageal nerve mass can be divided into two main tracts on the basis of direction of the neuropiles. The dorsal tracts are contributed to from the motor or interneurons of each ganglion, whereas the ventral tracts are from incoming sensory axons.     

Serotonin in the leech central nervous system: anatomical correlates and behavioral effects

Summary Stridulation of grasshoppers is controlled by hemisegmental pattern generator subunits which probably are restricted to the metathoracic ganglion complex (TG3-complex). The coordination of left and right pattern generator subunits depends on commissures of the TG3-complex (Ronacher 1989). The coordination of the stridulatory movements was studied in Chorthippus dorsatus males with partial mediosagittal incisions in the TG3-complex.Animals bearing anterior incisions in the TG3-complex, by which all commissures of the metathoracic neuromere and the first abdominal neuromere were transected, were still able to produce bilaterally coordinated species-specific stridulatory movements. Commissures of the T3- and A1-neuromere, thus, are not necessary, and the A2-, A3-commissures are sufficient for this coordination (Figs. 3, 4).Animals with partial posterior incisions, extending until A1, had deficits in their stridulation pattern; the coordination between the hindlegs was impaired though not completely lost (Fig. 6). This is discussed in view of the structure of stridulation interneurons identified in a related grasshopper species (Omocestus viridulus).These results indicate an unexpected substantial contribution of the abdominal neuromeres A2 and A3 to the control of stridulatory movements. This constitutes an interesting parallel to the flight control system of locusts where interneurons located in the first 3 abdominal neuromeres also appear to contribute to the flight pattern generator (Robertson et al. 1982).Abbreviations A1–A3 abdominal neuromeres 1–3 - T3 metathoracic neuromere - TG3-complex metathoracic ganglion complex including A1–A3     

Central connections of the olfactory bulb in the weakly electric fish,Gnathonemus petersii

Summary We have investigated the central connections of the classical olfactory system in the weakly electric fish Gnathonemus petersii using HRP and cobalt labelling techniques. The olfactory bulb projects bilaterally via the medial and lateral olfactory tracts to restricted areas of the telencephalon, namely to its rostromedial, lateral and posterior medial parts. The most extensive telencephalic target is the posterior terminal field, which arcs around the lateral forebrain bundle at levels posterior to the anterior commissure. Projections to the contralateral hemisphere cross in the ventral telencephalon rostral to the anterior commissure and via the posterior dorsal part of the anterior commissure; endings are also present within the anterior commissure. Bilateral projections to the preoptic area, to the nucleus posterior tuberis and to an area in the thalamus are apparent. In all cases, contralateral projections are less extensive than those on the side ipsilateral to the injected bulb. A projection via the medial olfactory tract can be followed to the contralateral bulb. Following injections into the olfactory bulb, retrogradely labelled neurons are found in the contralateral bulb and in six telencephalic areas; they are also present in the periventricular diencephalon and in an area lateral to the nucleus posterior tuberis. The present results support the suggestion that a reduction in olfactory input to the telencephalon occurs together with increased telencephalic differentiation in actinopterygian fishes.     

Topographical organization of the auditory pathway within the prothoracic ganglion of the cricket Gryllus campestris L.

Summary The topographical organization of the prothoracic ganglion of the cricket, Gryllus campestris L., is described from horizontal, transverse, and sagittal sections of preparations specially treated to elucidate longitudinal tracts, commissures, and areas of neuropil. These structures were compared to those reported from other insect thoracic ganglia, resulting in still further evidence for a common basic morphological pattern among insect central nervous systems.Six types of auditory interneurons, all existing as mirrorimage pairs, were identified through intracellular application of the dye Lucifer yellow, and then related to several morphological patterns. Two intrasegmental neurons (ON1, ON2) are similar in location of cell bodies and course of neurites and axons; three intersegmental neurons (AN1, AN2, TN1) are likewise similar to one another. The axons of the two intrasegmental neurons cross the midline of the ganglion in the newly described omega commissure. Axons of the other four types all course within the median portion of the ventral intermediate tract and project intersegmentally.All six neuron types arborize within the ventral portion of the ring tract, the same neuropilar region in which auditory sensory neurons terminate. The ring tract is therefore considered the most important region for auditory information processing within the cricket prothoracic ganglion.     

Patterns and projections of crustacean cardioactive-peptide-immunoreactice neurones of the terminal ganglion of crayfish

Three distinct clusters of crustacean cardioactive-peptide-immunoreactive neurones occur in the terminal abdominal ganglion of the crayfish species Orconectes limosus, Astacus leptodactylus, Astacus astacus and Procambarus clarkii, as revealed by immunocytochemistry of whole-mount preparations and sections. They exhibit similar topology and projection patterns in all four studied species. An anterior ventral lateral and a posterior lateral cluster contain one small, strongly stained perikaryon and two large, less intensely stained perikarya, each showing contralateral projections. A posterior medial lateral cluster of up to six cells also contains these two types of perikarya. Whereas the small type perikarya belong to putative interneurones, the large type perikarya give rise to extensive neurohaemal plexuses in perineural sheaths of the third roots of the fifth abdominal ganglia, the connectives, the dorsal telson nerves, the ganglion itself, its roots and arteriolar supply. Thin fibres from these plexuses reach newly discovered putative neurohaemal areas around the hindgut and anus via the intestinal and the anal nerves, and directly innervate the phasic telson musculature. A comparison with earlier investigations of motoneurones and segmentation indicates that these three cell groups containing putative neurosecretory neurones may be members of at least three neuromeres in this ganglion. Crustacean cardioactive peptide released from these neurones may participate in the neurohumoral and modulatory control of different neuronal and muscle targets, thereby exceeding its previously established hindgut and heart excitatory effects.Abbreviations AG abdominal ganglion - adpl arteria dorsalis pleica - Ala arreria lateralis abdominalis - Asub arteria subneuralis - CCAP crustacean cardioactive peptide - CNS central nervous system - IR immunoreactive - LG lateral giant axon - LTr lateral tract - MDT medial dorsal tract - MG medial giant axon - M Tr medial tract - mcan musculus compressor ani - mfltp museulus flexor telsonos posterior - nan nervus ani (AG6 N5) - nant nervus anterior (AG6 N1, N2) - nia nervus intestinal anterior - nin nervus intestinalis (AG6 N7) - nip nervus intestinalis posterior - nteld nervus telsonos dorsalis (AG6 N6) - nielv nervus telsonos ventralis (AG6 N4) - nur nervus uropedalis (AG6 N3) - nven nervus ventralis (AG5 N3) - PIR peri-intestinal ring - PTF posterior telson flexor - VLT ventral lateral tract - VMT ventral medial tract - VNC ventral nerve cord - VIF ventral telson flexor - AVLC, PLC, PMLC anterior ventral lateral, posterior lateral, posterior medial lateral CCAP-immunoreactive cell cluster - A6AVC, A7AVC anterior ventral commissures - A7DCI dorsal commissure I - A7PVC posterior ventral commissure - A7SCII sensory commissure II - A7VCII, A7VCIII ventral commissures II and III of the sixth (A6) and seventh (A7) abdominal neuromer     

Origin of the pituitary innervation in the goldfish

Despite the large number of studies devoted to the pituitary of teleosts, the origin of the direct pituitary innervation is still largely unknown. Although such a model is ideal for applying retrograde transport techniques, these methods involve the difficult in vivo injection of tracers into the pituitary and have never been applied. Recently, a lipophilic fluorescent dye (1-1-dioctadecyl-3,3,3,3-tetramethylindocarbocyanin; DiI) has been introduced and shown to have the capacity of being transported by the membranes of paraformaldehydefixed tissues. Microcrystals of DiI were implanted via a ventral approach into the pituitary of goldfish previously fixed by intracardiac perfusion of paraformaldehyde. The goldfish heads were kept immersed in paraformaldehyde for various periods of time (2–6 weeks). The brains were then dissected and cut transversally using a Vibratome. The results demonstrate that hypophysiotrophic areas are essentially restricted to the preoptic region, the mediobasal hypothalamus and the nucleus dorsolateralis thalami. In addition, cell bodies probably containing gonadotrophin releasing-hormone were also retrogradely stained along a pathway that can be traced up to the olfactory bulbs. The results also confirm that cell bodies, located around the ventral aspect of the preoptic recess and probably corresponding to dopaminergic neurons, project to the pituitary. Large neurons have also been observed in the rostral dorsal midbrain tegmentum just caudal to the posterior commissure. Most neurons of the so-called paraventricular organ remain unstained. Finally, a fiber tract originating from an undetermined territory of the posterior brain has been observed. The results are discussed in relation to the possible chemical nature of the hypophysiotropic neurons.     

Serotonin-like immunoreactivity in the ventral nerve cord of the Colorado potato beetle,Leptinotarsa decemlineata: Identification of five different neuron classes

Summary In an immunohistochemical study of the ventral nerve cord of L. decemlineata, five distinct neuron categories were distinguished: 1) Two paired segmental twin interneurons occur in each ganglion or neuromere; their axons distribute processes over almost the entire nerve cord and run to the cerebral ganglion complex. In contrast, other axons are distributed locally. 2) Four large frontal neurosecretory neurons occur in the suboesophageal ganglion (SOG), two of which have axons that run into the mandibular nerves to form a neurohemal plexus on the surface of cerebral nerves. 3) A pair of large caudal neurons occur in the terminal ganglion and innervate the hindgut. 4) Local miniature interneurons occur in the SOG. 5) Terminal neurons are present in the last abdominal ganglion. Segmental twin interneurons appear to be grouped into 3 functional units spanning several ganglia. Their axons run to specific projection areas, which separate the functional units, and which mark the externally visible separation of condensed ganglion complexes. A possible role of the most caudal functional unit might be the synaptic control of caudal neurons innervating the hindgut.     

Localization of ovulation hormone-like neuropeptide in the central nervous system of the snail Lymnaea stagnalis by means of immunocytochemistry and in situ hybridization

Summary The caudo-dorsal cells (CDC) in the cerebral ganglia of the pond snail Lymnaea stagnalis synthesize the 36-amino acid ovulation hormone (CDCH). We have used immuno-cytochemistry and in situ hybridization to reveal the localization of neurons and axons containing CDCH-like material.A monoclonal antibody to a fragment of CDCH and a cDNA probe encoding CDCH reacted with the CDC-system, with specific cell groups in the cerebral and pleural ganglia, and with individually occurring neurons throughout the central nervous system. The cells in the pleural ganglia, which were found in about 50% of the preparations studied, are considered as ectopic CDC. They are morphologically similar to CDC in their somal dimensions and axonal organization. By means of immuno-electron microscopy it was shown that these neurons contain secretory vesicles that are similar to those of the CDC. The neurons of the bilateral groups occurring in the cerebral ganglia in addition to the CDC are smaller and more intensely stained than the CDC. Axons of these small neurons probably have varicosities located on the CDC axons in the neuropil of the cerebral ganglion, indicating synaptic contacts. Two major axon tracts could be followed from (or toward) the neuropil of the cerebral ganglion. One tract runs from the cerebral gangion via the pleural and parietal ganglia to the visceral ganglion, giving off branches to most nerves emanating from these ganglia. The other tract could be traced through the cerebro-pedal connective to the pedal ganglia. Only in the right pedal ganglion was extensive axonal branching observed. The nerves emanating from this ganglion contained many more immunoreactive axons than those from the left pedal ganglion. A polyclonal antibody raised against the synthetic fragment of CDCH stained, in addition to the neurons and axons revealed with the monoclonal antibody and the cDNA probe, three other major groups of neurons. Two are located in the cerebral ganglion, the other in the left pedal ganglion.The present findings suggest the presence of a system of neurons that contain CDCH or CDCH-like peptides. The role this system may play in the control of egg-laying and egg-laying behaviour is discussed.     

Monoamines in the nervous system of the tube-wormChaetopterus variopedatus (Polychaeta): Biochemical detection and serotonin immunoreactivity

Summary The presence and distribution of biogenic monoamines in the tube-wormChaetopterus variopedatus were investigated by a radioenzymatic method and HPLC with electrochemical detection, and the cellular localization of serotonin by peroxidase-antiperoxidase (PAP) immunohistochemistry with an antibody against serotonin-formaldehyde-protein conjugate. Dopamine, norepinephrine, epinephrine, serotonin (5-HT) and some of their metabolites were detectable, dopamine and norepinephrine being present in substantially larger amounts than 5-HT and epinephrine. With few exceptions, the largest amounts of amines were localized in the most nerve-rich tissues such as tentacles, and those containing cerebral ganglia and the ventral nerve cord. Serotonin-immunoreactive unipolar neurons were widely distributed in the dorso-lateral cerebral ganglia, the neurosecretory pharyngeal ganglion and the segmental ganglia of the anterior (dorsolateral) and posterior (medioventral) nerve cords. Some nerve-fiber tracts stained in the cerebral ganglia, but the neuropiles of segmental ganglia were the most intensely reactive CNS structures. Numerous reactive fibers were also present in connectives, commissures and segmental nerves. All peripheral sensory structures included serotonin-immunoreactive cells and neurites, especially the parapodial cirri and the bristle receptors of the setae. Trunk and parapodial muscles contained reactive varicose fibers and neuronal somata. These results suggest that monoamines are abundant and widespread in these worms and that 5-HT appears to have a key sensory role.     

Localization of cholecystokinin-like immunoreactivity in the central nervous system of Triatoma infestans (Insecta: Heteroptera)

The distribution of cholecystokinin-like immunoreactivity was studied in the central nervous system of the heteropteran insect Triatoma infestans using high-sensitivity immunocytochemistry. In the protocerebrum, CCK-IR somata were observed in the anteromedial, anterolateral and posterior cell-body layers. The neuropils displayed different densities of immunoreactive neurites. Few immunoreactive somata were found in the optic lobe in both the medial and lateral soma rinds, as well as in the proximal optic lobe. Immunoreactive fibers were present in the medulla and lobula neuropils. The sensory deutocerebrum contained a higher number of immunopositive perikarya than the antennal mechanosensory and motor center. The antennal lobe glomeruli displayed a moderate density of immunoreactive fibers. With regard to the subesophageal ganglion, numerous CCK-IR somata were found close to the root of the mandibular nerve; others were present in the soma rind of the remaining neuromeres. CCK-IR perikarya were present in both thoracic ganglia, with the abdominal neuromeres containing the highest number of positive somata. The neuropils of both ganglia showed moderate densities of immunopositive processes. The distribution of CCK-LI in somata and neuropils of central nervous system of T. infestans is widespread suggesting that a CCK-like peptide may act mainly as a neuromodulator in the integration of information from distinct sensory receptors.     

Serotonin-immunoreactive and dopamine-immunoreactive neurones in the terminal ganglion of the cricket,Acheta domestica: Light- and electron-microscopic immunocytochemistry

Summary The distribution and ultrastructure of serotonin- and dopamine-immunoreactive (5-HTi and DAi) neurones have been investigated in the terminal ganglion of the cricket, Acheta domestica, using a pre-embedding chopper technique. Special attention has been paid to the immunoreactive structures in the neuropil. 5-HTi structures are extensively distributed and densely packed throughout the 5 neuromeres of the terminal ganglion and originate from several interneurones and efferent neurones. In contrast, DAi fibres are distributed sparsely although they extend to all neuromeres of the ganglion and originate from 6 interneurons only. For both 5-HTi and DAi neurones characteristic axonal projections and branching patterns can be distinguished. The 5-HTi axons exhibit rich varicose arborizations, whereas DAi neurones possess fewer varicosities in the neuropil. Electron microscopy shows that 5-HTi varicosities contain small ( 60 nm) and large ( 100 nm) agranular vesicles, and large ( 100 nm) granular vesicles, whereas in DAi varicosities small ( 60 nm) agranular and large ( 100 nm) granular vesicles are seen. Both 5-HTi and DAi varicosities form synaptic contacts. We conclude that both serotonin and dopamine may be used as neurotransmitters in the terminal ganglion of the cricket.Fellow of the Alexander von Humboldt-Stiftung     

Regeneration of pedal ganglion neurons in the sea butterfly Clione limacina

In the pedal ganglia ofClione limacina the growth of neurites is traced in motoneurons after transection of the wing nerve and in interneurons after transection of the pedal commissure. Neurons were stained intracellularly with Lucifer yellow. In the motoneurons the neurites growing from the transected end of the axon and from the neuron soma spread to all nerve trunks departing from the ipsi- and contralateral ganglia. For nerve transection in the intact mollusk, wing movements were restored 10 days after the operation. In the interneurons the growing neurites branched within the pedal ganglion or spread to the cerebral ganglia, but they never reached the periphery.Institute of Problems of Information Transmission, Academy of Sciences of the USSR, Moscow. M. V. Lomonosov State University, Moscow. Translated from Neirofiziologiya, Vol. 17, No. 4, pp. 449–455, July–August, 1985.     

Monoaminhaltige Strukturen im Zentralnervensystem der Trichoptera (Insecta) Teil II

Zusammenfassung Mit Hilfe der fluoreszenzmikroskopischen Methode nach Falck und Hillarp wurden die monoaminhaltigen Strukturen im Zentralnervensystem einiger Trichopteren untersucht (vgl. Klemm, 1968). Im Protocerebrum können vier Gruppen von katecholamin-haltigen Zellkörpern unterschieden werden. Eine weitere unregelmäßig darstellbare Gruppe von globulösen Perikarya liegt im Lobus opticus. Fluoreszierende Varikositäten durchsetzen locker das Cerebralganglion und sind in folgenden Neuropilstrukturen konzentriert: Medulla, Lobula, Corpus centrale, Nodulus, Corpus ventrale, - und -Lobus und Lobus communis. Letzterer verbindet den - und den -Lobus mit dem nicht fluoreszierenden Pedunculus. In der Lamina, in der accessorischen Medulla, in der Pons cerebralis, im Tuberculum opticum, im Tractus olfactorio-globularis, im Pedunculus, im Stielglomerulus und in den Globulizellen ließen sich keine Katecholamine nachweisen. Zwischen dem monoaminhaltigen Lobus communis und dem nicht fluoreszierenden Pedunculus besteht eine scharfe Grenze. Fluoreszierende variköse Fasern und einzelne fluoreszierende Perikarya befinden sich im Deuto- und Tritocerebrum. Zwei fluoreszierende Bahnen können im Cerebralganglion unterschieden werden: 1. Stratum caudale, 2. Tractus ventralis. Letzterer beginnt mit seiner Pars anterior und posterior im dorsalen fluoreszierenden Neuropil des Protocerebrum. Die beiden Teile laufen frontal und caudal um den Zentralkörper herum und vereinigen sich unterhalb des Zentralkörpers in der Pars communis. Von hier aus zieht der paarige Tractus ventralis bis in das Tritocerebrum. Die Frage einer Homologisierung dieser Bahnen wird diskutiert.Ähnlich wie im Ganglion suboesophageale sind in den drei thorakalen und fünf separaten abdominalen Ganglien zwei Paar fluoreszierender Zellkörper vorhanden, in denen Dopamin mikrospektrofluorimetrisch festgestellt werden konnte. Ein Paar dieser Zellen liegt caudoventral, das andere dorso-median bis dorso-caudal. Ihre Zellfortsätze und Abzweigungen werden beschrieben. In einzelnen Fällen konnte noch ein zweites dorsales Paar fluoreszierender Perikarya sichtbar gemacht werden. Das letzte Ganglion der Bauchkette setzt sich aus zwei bis drei Gangliomeren zusammen. Die Anzahl ihrer fluoreszierenden Perikarya ist reduziert. Das Neuropil der Ganglien im Bauchmark ist von monoaminhaltigen Fasern durchsetzt, wobei sich in der dorsalen Hälfte mehr fluoreszierendes Neuropil befindet als in der ventralen. Lateral in den Ganglien sind die monoaminhaltigen varikösen Fasern vorwiegend dorsoventrad angeordnet. Im medianen Teil laufen sie in Längsrichtung, verzweigen sich und setzen sich in die Konnektive fort und verbinden die katecholaminhaltigen Neuropilbereiche der einzelnen Ganglien miteinander.

---

Monoamine-containing structures in the central nervous system in Trichoptera (Insecta). Part II

Summary The distribution of monoamine-containing structures in the central nervous system of Trichoptera has been investigated with the histochemical fluorescence method of Falck and Hillarp (cf. also Klemm, 1968). In the protocerebrum, four groups of catecholamine containing perikarya can be distinguished. Another group of irregularly appearing cell bodies is situated in the optical lobe. Fluorescent varicosities occur scattered throughout the cerebral ganglion, being concentrated in the following neuropile areas: In the medulla, the lobula, the corpus centrale, the noduli, the corpora ventralia, and the - and -lobes, as well as in the lobus communis where the - and -lobes join the non-fluorescent pedunculus. In the lamina, the accessory medulla, the pons cerebralis, the tuberculum opticum, the tractus olfactorio-globularis, the pedunculus including its glomerular region, and the globuli-cells, no catecholamines are detectable. There is a sharp borderline between the monoamine-containing lobus communis and the non-fluorescent pedunculus. Fluorescent varicose fibres and single fluorescent perikarya occur in the Deuto- and Tritocerebrum. Two fluorescent tracts can be distinguished in the cerebral ganglion: 1. Stratum caudale. 2. Tractus ventralis. The pars anterior and pars posterior of the tractus ventralis begin in the dorsal fluorescent neuropile of the cerebral ganglion and join underneath the central body into their pars communis. From this, it can be traced as tractus ventralis into the tritocerebrum. The possible homologies of these tracts are discussed. Similar to the ganglion suboesophageale, the three thoracal and the five separate abdominal ganglia contain two paires of fluorescent cell bodies. Microspectrofluorometrically a content of dopamine in these cells could be established. One pair lies caudoventrally. The two other cell bodies are situated dorso-medially to dorso-caudally; their position varies notably, especially in the abdominal ganglia. The cell process and its arborisations are described. Occasionally a second dorsal cellpair could be observed. The last ganglion of the abdominal chain is composed of at least two gangliomeres with a reduced number of fluorescent perikarya. The neuropile of the thoracal- and abdominal ganglia is penetrated by monoamine-containing fibres, with a predominance in the dorsal half. In the ganglia, the fluorescent varicose fibres are mainly oriented dorso-ventrally in the lateral part and longitudinally in the medial part, where they branch and continue into the connectives. In this way, the catecholamine-containing neuropiles of adjacent ganglia are connected to each other.

Die vorliegende Arbeit wurde unterstützt durch The Swedish Medical Research Council (No. B70-14X-56-06 und B70-14X-05).