Distribution of GABA-like immunoreactive neurons in the slug Limax maximus

Summary Immunohistochemical techniques were used to study the distribution of gamma-amino butyric acid (GABA)-like immunoreactive neurons in the nervous system of the slug Limax maximus. Approximately 170 GABA-like immunoreactive cell bodies were found in the central nervous system. These were located in the cerebral, buccal and pedal ganglia. Most GABA-like immunoreactive neurons had small cell bodies, which were aggregated into discrete clusters within the cerebral and pedal ganglia. Three pairs of longer, uniquely identifiable, GABA-like immunoreactive cells were found in the cerebral ganglion. GABA-like immunoreactive nerve fibres were also found in all of the central ganglia but were absent from peripheral nerves. These results suggest that GABA acts as a central neurotransmitter in the slug. The possible roles of GABA-ergic neurotransmission in the slug are discussed.     

Transplantation of neurons reveals processing areas and rules for synaptic connectivity in the cricket nervous system

In order to assess the nature of spatial cues in determining the characteristic projection sites of sensory neurons in the CNS, we have transplanted sensory neurons of the cricket Acheta domesticus to ectopic locations. Thoracic campaniform sensilla (CS) function as proprioceptors and project to an intermediate layer of neuropil in thoracic ganglia while cercal CS transduce tactile information and project into a ventral layer in the terminal abdominal ganglion (TAG). When transplanted to ectopic locations, these afferents retain their modality-specific projection in the host ganglion and terminate in the layer of neuropil homologous to that of their ganglion of origin. Thus, thoracic CS neurons project to intermediate neuropil when transplanted to the abdomen and cercal CS neurons project to a ventral layer of neuropil when transplanted to the thorax. We conclude that CS can be separated into two classes based on their characteristic axonal projections within each segmental ganglion. We also found that the sensory neurons innervating tactile hairs project to ventral neuropil in any ganglion they encounter after transplantation. Ectopic sensory neurons can form functional synaptic connections with identified interneurons located within the host ganglia. The new contacts formed by these ectopic sensory neurons can be with normal targets, which arborize within the same layer of neuropil in each segmental ganglion, or with novel targets, which lack dendrites in the normal ganglion and are thus normally unavailable for synaptogenesis. These observations suggest that a limited set of molecular markers are utilized for cell–cell recognition in each segmentally homologous ganglion. Regenerating sensory neurons can recognize novel postsynaptic neurons if they have dendrites in the appropriate layer of neuropil. We suggest that spatial constraints produced by the segmentation and the modality-specific layering of the nervous system have a pivotal role in determining synaptic specificity. © 1993 John Wiley & Sons, Inc.     

两种软体动物神经系统一氧化氮合酶的组织化学定位

运用一氧化氮合酶(NOS)组织化学方法研究了软体动物门双壳纲种类中国蛤蜊和腹足纲种类嫁Qi神经系统中NOS阳性细胞以及阳性纤维的分布。结果表明：在蛤蜊脑神经节腹内侧,每侧约有10-15个细胞呈强NOS阳性反应,其突起也呈强阳性反应,并经脑足神经节进入足神经节的中央纤维网中;足神经节内只有2个细胞呈弱阳性反应,其突起较短,进入足神经节中央纤维网中,但足神经节中,来自脑神经节阳性细胞和外周神经系统的纤维大多呈NOS阳性反应;脏神经节的前内侧部和后外侧部各有一个阳性细胞团,其突起分别进入后闭壳肌水管后外套膜神经和脑脏神经索。脏神经节背侧小细胞层以及联系两侧小细胞层的纤维也呈NOS阳性反应。嫁Qi中枢神经系统各神经节中没有发现NOS阳性胞体存在;脑神经节、足神经节、侧神经节以及脑—侧、脑—足、侧—脏连索中均有反应程度不同的NOS阳性纤维,这些纤维均源于外周神经。与已研究的软体动物比较,嫁Qi和前鳃亚纲其它种类一样,神经系统中NO作为信息分子可能主要存在于感觉神经。而中国蛤蜊的神经系统中一氧化氮作为信息分子则可能参与更广泛的神经调节过程。     

Origins of the insect enteric nervous system: differentiation of the enteric ganglia from a neurogenic epithelium.

The enteric nervous system (ENS) of the moth Manduca sexta is organized into two distinct cellular domains: an anterior domain that includes several small ganglia on the surface of the foregut, and a more posterior domain consisting of a branching nerve plexus (the enteric plexus) that spans the foregut-midgut boundary. Previously, we showed that the neurons of the posterior domain, the enteric plexus, are generated from a large placode that invaginates from the caudal lip of the foregut; subsequently, the cells become distributed throughout the enteric plexus by a sequence of active migration. We now demonstrate that the neurons of the anterior domain, the cells of the enteric ganglia, arise via a distinct developmental sequence. Shortly after the foregut has begun to form, three neurogenic zones differentiate within the foregut epithelium and give rise to chains of cells that emerge onto the foregut surface. The three zones are not sites of active mitosis, as indicated by the absence of labelling with a thymidine analogue and by clonal analyses using intracellularly injected dyes. Rather, the zones serve as loci through which epithelial cells are recruited into a sequence of delamination and neuronal differentiation. As they emerge from the epithelium, the cells briefly become mitotically active, each cell dividing once or twice. In this manner, they resemble the midline precursor class of neural progenitors in the insect central nervous system more than neuroblast stem cells. The progeny of these zone-derived precursors then gradually coalesce into the ganglia and nerves of the anterior ENS. Although this reorganization results in some variability in the precise configuration of neurons within the ganglia, the overall morphology of the ganglia is highly stereotyped, consisting of cortical layers of cells that surround a ventral neuropil. In addition, a number of the neurons within the frontal and hypocerebral ganglia express identifiable phenotypes in a manner that is similar to many cells of the insect central nervous system. These observations indicate that the differentiation of the enteric ganglia in Manduca involves an unusual combination of features seen during the formation of other regions of the nervous system and, as such, constitutes a distinct program of neurogenesis.     

PBAN/pyrokinin peptides in the central nervous system of the fire ant, <Emphasis Type="Italic">Solenopsis invicta</Emphasis>

The pyrokinin/pheromone-biosynthesis-activating neuropeptide (PBAN) family of peptides found in insects is characterized by a 5-amino-acid C-terminal sequence, FXPRLamide. The pentapeptide is the active core required for diverse physiological functions, including the stimulation of pheromone biosynthesis in female moths, muscle contraction, induction of embryonic diapause, melanization, acceleration of puparium formation, and termination of pupal diapause. We have used immunocytochemical techniques to demonstrate the presence of pyrokinin/PBAN-like peptides in the central nervous system of the fire ant, Solenopsis invicta. Polyclonal antisera against the C-terminal end of PBAN have revealed the location of the peptide-producing cell bodies and axons in the central nervous system. Immunoreactive material is detectable in at least three groups of neurons in the subesophageal ganglion and corpora cardiaca of all adult sexual forms. The ventral nerve cord of adults consists of two segmented thoracic ganglia and four segmented abdominal ganglia. Two immunoreactive pairs of neurons are present in the thoracic ganglia, and three neuron pairs in each of the first three abdominal ganglia. The terminal abdominal ganglion has no immunoreactive neurons. PBAN immunoreactive material found in abdominal neurons appears to be projected to perisympathetic organs connected to the abdominal ganglia. These results indicate that the fire ant nervous system contains pyrokinin/PBAN-like peptides, and that these peptides are released into the hemolymph. In support of our immunocytochemical results, significant pheromonotropic activity is found in fire ant brain-subesophageal ganglion extracts from all adult fire ant forms (queens, female and male alates, and workers) when extracts are injected into decapitated females of Helicoverpa zea. This is the first demonstration of the presence of pyrokinin/PBAN-like peptides and pheromonotropic activity in an ant species. This research was supported in part by a US-Israel Binational Science Foundation Grant (no. 2003367).     

Distribution of serotonin-like immunoreactive neurons in the slug<Emphasis Type="Italic"> Limax valentianus</Emphasis>

Immunohistochemical techniques were used to study the distribution of serotonin-containing neurons in the nervous system of the slug Limax valentianus. Approximately 350 serotonin-like immunoreactive cell bodies were found in the central nervous system. These were located in the cerebral, pedal, visceral and right parietal ganglia. Most serotonin-like immunoreactive neurons had small cell bodies, which were aggregated into discrete clusters. A pair of previously identified metacerebral giant cells were found on the anterior side of the cerebral ganglion, and two additional pairs of uniquely identifiable, serotonin-like immunoreactive cells were found on the posterior side of the cerebral ganglion. The whole-mount maps of these stained neurons will be useful in further physiological and biochemical studies of olfactory learning at the cellular level in Limax valentianus.This study was supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Science, Sports and Technology, Japan (nos. 12307053 and 13771353)     

Distribution and anatomy of GABA-like immunoreactive neurons in the central and peripheral nervous system of the snail Helix pomatia

Gamma-aminobutyric acid (GABA)-like immunoreactive neurons were studied in the central and peripheral nervous system of Helix pomatia by applying immunocytochemistry on whole-mount preparations and serial paraffin sections. GABA-immunoreactive cell bodies were found in the buccal, cerebral and pedal ganglia, but only GABA-immunoreactive fibers were found in the viscero-parietal-pleural ganglion complex. The majority of GABA-immunoreactive cell bodies were located in the pedal ganglia but a few could be found in the buccal ganglia. Varicose GABA-ir fibers could be seen in the neuropil areas and in distinct areas of the cell body layer of the ganglia. The majority of GABA-ir axonal processes run into the connectives and commissures of the ganglia, indicating an important central integrative role of GABA-immunoreactive neurons. GABA may also have a peripheral role, since GABA-immunoreactive fibers could be demonstrated in peripheral nerves and the lips. Glutamate injection did not change the number or distribution of GABA-immunoreactive neurons, but induced GABA immunoreactivity in elements of the connective tissue ensheathing the muscle cells and fibers of the buccal musculature. This shows that GABA may be present in different non-neural tissues as a product of general metabolic pathways.     

Afferent projections of infrared-sensitive sensilla in the beetle Melanophila acuminata (Coleoptera: Buprestidae)

Beetles of the genus Melanophila are able to detect infrared radiation by using specialized sensilla in their metathoracic pit organs. We describe the afferent projections of the infrared-sensitive neurons in the central nervous system. The axons primarily terminate in the central neuropil of the fused second thoracic ganglia where they establish putative contacts with ascending interneurons. Only a few collaterals appear to be involved in local (uniganglionic) circuits. About half of the neurons send their axons further anterior to the prothoracic ganglion. A subset of these ascend to the subesophageal ganglion, and about 10% project to the brain. Anatomical similarities suggest that the infrared-sensitive neurons are derived from neurons supplying mechanosensory sensilla. The arborization pattern of the infrared afferents suggests that infrared information is processed and integrated upstream from the thoracic ganglia.     

Identification of two cardioacceleratory neurons in the isopod crustacean, Ligia exotica and their effects on cardiac ganglion cells

We identified two pairs of cardioacceleratory (CA1, CA2) neurons in the central nervous system of the isopod Ligiaexotica and examined their effects on the cardiac ganglion (CG). CA1 neurons had cell bodies in the 2nd thoracic ganglion and had arborizations in the subesophageal ganglion and the 1st and 2nd thoracic ganglia. CA2 neurons had cell bodies in the 3rd thoracic ganglion and had arborizations in the 2nd, 3rd and 4th thoracic ganglia. They sent axons to the heart through the ipsilateral 3rd roots of the ganglia where their cell bodies were located. Repetitive stimulation of the CA1 axon rapidly increased the burst frequency of the CG, and that of CA2 rather slowly. The increased burst rate caused by the CA1 stimulation was significantly higher than that caused by CA2. Overall depolarization of a quiescent CG cell produced by the CA1 stimulation was significantly larger in amplitude than that produced by CA2. Facilitation was obviously seen in the excitatory post-synaptic potentials evoked by the CA1 stimulation. These results show that the synaptic properties of CA1 and CA2 neurons are different, suggesting that they have different functional roles in heart regulation. Accepted: 19 July 1997     

Migration of neurons between ganglia in the metamorphosing insect nervous system

Migration of neurons over long distances occurs during the development of the adult central nervous system of the sphinx moth Manduca sexta, and the turnip moth Agrotis segetum. From each of the suboesophageal and three thoracic ganglia, bilaterally-paired clusters of immature neurons and associated glial cells migrate posteriorly along the interganglionic connectives, to enter the next posterior ganglion. The first sign of migration is observed at the onset of metamorphosis, when posterio-lateral cell clusters gradually separate from the cortex of neuronal cell bodies and enter the connectives. Cell clusters migrate posteriorly along the connective to reach the next ganglion over the first three days (approximately 15%) of pupal development. During migration, each cell cluster is completely enveloped by a single giant glial cell spanning the entire length of the connective between two adjacent ganglia. Intracellular cobalt staining reveals that each migrating neuron has an ovoid cell body and an extremely long leading process which extends as far as the next posterior ganglion; this is not a common morphology for migrating neurons that have been described in vertebrates. Once the cells arrive at the anterior cortex of the next ganglion, they rapidly intermingle with the surrounding neurons and so we were unable to determine the fate of the migrating neurons at their final location.     

Localization of pigment-dispersing hormone (PDH) immunoreactivity in the central nervous system of Carcinus maenas and Orconectes limosus (Crustacea), with reference to FMRFamide immunoreactivity in O. limosus

Summary By use of antisera raised against synthetic pigment-dispersing hormone (PDH) of Uca pugilator and FMRFamide, the distribution of immunoreactive structures in the central nervous system (CNS) of Carcinus maenas and Orconectes limosus was studied by light microscopy. In both species, a total of 10–12 PDH-positive perikarya occur amongst the anterior medial, dorsal lateral and angular somata of the cerebral ganglion (CG). In C. maenas, one PDH-perikaryon was found in each commissural ganglion (COG) and several more in the thoracic ganglion. In O. limosus, only four immunopositive perikarya could be demonstrated in the ventral nerve cord, i.e., two somata in the anterior and two in the posterior region of the suboesophageal ganglion (SOG). PDH-immunoreactive tracts and fiber plexuses were present in all central ganglia of both species, and individual axons were observed in the connectives. FMRFamide-immunoreactivity was studied in O. limosus only. Neurons of different morphological types were found throughout the entire CNS, including numerous perikarya in the anterior medial, anterior olfactory, dorsal lateral and posterior cell groups of the CG. Four perikarya were found in the COG, six large and numerous smaller ones in the SOG, and up to eight cells in each of the thoracic and abdominal ganglia. In each ganglion, the perikarya form fiber plexuses. Axons from neurons belonging to the CG could be traced into the ventral nerve cord; nerve fibers arising from perikarya in the SOG appeared to project to the posterior ganglia. In none of the structures examined colocalization of PDH- and FMRF-amide-immunoreactivity was observed.Dedicated to Prof. K.-E. Wohlfarth-Bottermann on the occasion of his 65th birthday     

A comparative ultrastructural and physiological study on melanophores of wild-type and periodic albino mutants of Xenopus laevis

Summary The central and visceral nervous systems of the cockroach Periplaneta americana were studied by means of the peroxidase-antiperoxidase immunocytochemical method, with the use of antibody to bovine pancreatic polypeptide (PP). PP-like immunoreactive neuron somata are most numerous in the brain; at least 6 pairs of cell groups occur in clearly defined regions. Three pairs of cells each are also present in the suboesophageal ganglion and the thoracic ganglia, one pair of a single cell each in the first abdominal and the frontal ganglia, and 4 to 6 pairs of single cells in the terminal ganglion. No reactive cells were found in the retrocerebral complex and the second to the fifth abdominal ganglia. The axons containing PP-like immunoreactivity issue many branches that are distributed in the entire brain-retrocerebral complex, ventral cord, and visceral nervous system. PP-like immunoreactive material produced in the brain seems to be transported by three routes: protocerebrum to corpora cardiaca (-allata) through the nervi corporis cardiaci, tritocerebrum to visceral nervous system through frontal commissures, and to ventral cord through circumoesophageal connectives.A possible homology between the mammalian brain-GEP (gastro-enteropancreatic) system and the brain-midgut system of this insect is discussed.     

Neural substrate and allatostatin-like innervation of the gut of Locusta migratoria

Allatostatin-like immunoreactivity (ALI) is widely distributed in processes and varicosities on the fore-, mid-, and hindgut of the locust, and within midgut open-type endocrine-like cells. ALI is also observed in cells and processes in all ganglia of the central nervous system (CNS) and the stomatogastric nervous system (SNS). Ventral unpaired median neurons (VUMs) contained ALI within abdominal ganglia IV-VII. Neurobiotin retrograde fills of the branches of the 11th sternal nerve that innervate the hindgut revealed 2-4 VUMs in abdominal ganglia IV-VIIth, which also contain ALI. The VIIIth abdominal ganglion contained three ventral medial groups of neurons that filled with neurobiotin and contained ALI. The co-localization of ALI in the identified neurons suggests that these cells are the source of ALI on the hindgut. A retrograde fill of the nerves of the ingluvial ganglia that innervate the foregut revealed numerous neurons within the frontal ganglion and an extensive neuropile in the hypocerebral ganglion, but there seems to be no apparent co-localization of neurobiotin and ALI in these neurons, indicating the source of ALI on the foregut comes via the brain, through the SNS.     

Distribution of dopamine and octopamine in the central nervous system and ovary during the ovarian maturation cycle of the giant freshwater prawn, Macrobrachium rosenbergii

Dopamine (DA), octopamine (OA) and serotonin (5-HT) are the key neurotransmitters that control gonadal development in decapod crustaceans. 5-HT stimulates, while DA and OA delay gonadal development in Macrobrachium rosenbergii. In the present study, we have further investigated the distribution patterns of DA and OA in the central nervous system (CNS) and ovary during various stages of the ovarian maturation cycle of this giant freshwater prawn. DA- and OA-immunoreactive neurons and fibers were distributed extensively in several regions of the brain, subesophageal ganglion (SEG), thoracic ganglia and abdominal ganglia. In the brain, the two neurotransmitters were present in neurons of clusters 6, 7, 11, 17, and nearby neuropil regions. In the SEG, thoracic ganglia and abdominal ganglia, immunoreactive neurons and fibers were found along the midline and in several neuronal clusters around each neuropil region. Staining for DA and OA was more intense in the thoracic ganglia than in other parts of the CNS. In the ovary, DA- and OA-immunoreactivities were present at high intensity in early oocytes. The presence of DA- and OA-immunoreactivities in neural ganglia as well as ovary suggests that DA and OA may also be involved in the reproductive process, particularly ovarian development and differentiation of oocytes in this species.     

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.     

The identification and distribution of gonadotropin-releasing hormone-like peptides in the central nervous system and ovary of the giant freshwater prawn, Macrobrachium rosenbergii

In the present study, we demonstrated the existence of GnRH-like peptides in the central nervous system (CNS) and ovary of the giant freshwater prawn, Macrobrachium rosenbergii using immunocytochemistry. The immunoreactivity (ir) of lamprey (l) GnRH-III was detected in the soma of medium-sized neurons located in neuronal cluster number 11 in the middle part of supraesophageal ganglion (deutocerebrum), whereas ir-octopus (oct) GnRH was observed in the soma of both medium-sized and large-sized neurons in thoracic ganglia, as well as in the fibers innervating the other medium-sized and large-sized neuronal cell bodies in the thoracic ganglia. In addition, ir-lGnRH-I was observed in the cytoplasm of late previtellogenic oocyte and early vitellogenic oocyte. These data suggest that M. rosenbergii contain at least three isoforms of GnRH: two GnRH isoforms closely related to lGnRH-III and octGnRH in the CNS, whereas another isoform, closely related to lGnRH-I, was localized in the ovary. This finding provides supporting data that ir-GnRH-like peptide(s) may exist in this decapod crustacean.     

Sensorin-A immunocytochemistry reveals putative mechanosensory neurons inLymnaea CNS

The pond snailLymnaea stagnalis is a useful model system for studying the neural basis of behaviour but the mechanosensory inputs that impact on behaviours such as respiration, locomotion, reproduction and feeding are not known. InAplysia, the peptide sensorin-A appears to be specific to a class of central mechanosensory neurons. We show that in theLymnaea central nervous system sensorin-A immunocytochemistry reveals a discrete pattern of staining involving well over 100 neurons. Identifiable sensorin positive clusters of neurons are located in the buccal and cerebral ganglia, and a single large neuron is immunopositive in each pedal ganglion. These putative mechanosensory neurons are not in the same locations as previously identified motoneurons, interneurons or neurosecretory cells. As would be expected for a mechanoafferent, sensorin positive fibres were found in nerve tracts innervating the body wall. This study lays the foundation for future electrophysiological and behavioural analysis of these putative mechanosensory neurons.     

Central nervous system projections to and from the commissural ganglion of the crab Cancer borealis

Higher-order inputs provide important regulatory control to motor circuits, but few cellular-level studies of such inputs have been performed. To begin studying higher-order neurons in an accessible model system, we have localized, in the supraesophageal ganglion (brain), neurons that are candidates for influencing the well-characterized motor circuits in the stomatogastric nervous system (STNS) of the crab Cancer borealis. The STNS is an extension of the central nervous system and includes four ganglia, within which are a set of motor circuits that regulate the ingestion and processing of food. These motor circuits are locally regulated by a set of modulatory neurons, most of which are located in the paired commissural ganglia (CoGs). These modulatory neurons are well-positioned to receive input from brain neurons because the circumesophageal commissures (CoCs) connect the brain with the CoGs. We have performed a series of CoC backfills to localize the brain neurons that are likely to innervate the CoGs and are, therefore, candidates for influencinng the STNS motor patterns. CoC backfill-labeled neuronal somata within the brain are clustered around a subset of anatomically defined neuropil regions. We have concomitantly localized many CoG neurons that project into the brain. This latter pathway presumably includes neurons that provide feedback regarding ongoing STNS activity. Interestingly, nearly all of these brain and CoG neurons project through the medial aspect of the CoC. This work provides an initial framework for future studies to determine the way that higher-order input regulates rhythmic motor patterns. This work was supported by a grant from the National Institute of Neurological Disorders and Strokes (NS42813 to M.P.N.) and a National Science Foundation Fellowship (DGE9616278 to M.S.K.).     

Wasp uses venom cocktail to manipulate the behavior of its cockroach prey

The sting of the parasitoid wasp Ampulex compressa is unusual, as it induces a transient paralysis of the front legs followed by grooming behavior and then by a long-term hypokinesia of its cockroach prey. Because the wasp's goal is to provide a living meal for its newborn larva, the behavioral changes in the prey are brought about by manipulating the host behavior in a way beneficial to the wasp and its offspring. To this end, the wasp injects its venom cocktail with two consecutive stings directly into the host's central nervous system. The first sting in the thorax causes a transient front leg paralysis lasting a few minutes. This paralysis is due to the presence of a venom component that induces a postsynaptic block of central cholinergic synaptic transmission. Following the head sting, dopamine identified in the venom appears to induce 30 min of intense grooming. During the long-term hypokinesia that follows the grooming, specific behaviors of the prey are inhibited while others are unaffected. We propose that the venom represses the activity of head ganglia neurons thereby removing the descending excitatory drive to the thoracic neurons.Abbreviations CNS central nervous system - DA dopamine - GI giant interneuron - PSP postsynaptic potential - SEG sub-esophageal ganglion - TI thoracic interneuron     

Localization of Lom-AG-myotropin I-like substances in the male reproductive and nervous tissue of the locust,Locusta migratoria

Summary Lom-AG myotropin I (Lom-AG-MTI) was the first peptide to be isolated from the male accessory reproductive glands of the locust, Locust migratoria. It shows no sequence similarity to any of the peptides identified from vertebrate or invertebrate tissues. A polyclonal antiserum was used to localize Lom-AG-MTI-like material in the male reproductive system and nervous system of the locust. Immunoreactivity was found in two of the hyaline gland tubules. In the brain, cell bodies were detected in the proto- and deuterocerebrum as well as the frontal ganglion. Nerve fibers were stained in the neuropils of the brain and throughout the labial nerves into the recurrent nerve. Thoracic and last abdominal ganglia contained neurons which could be stained with Lom-AG-MTI antiserum. The pronounced reactivity in the central nervous system suggests a possible neuroregulatory function of the peptide.