Enzyme histochemistry of basal ganglia in the septally cannulated rat.

Stereotaxic septal cannulation in one hemisphere of the rat results in displacement of the ipsilateral basal ganglion along its rostrocaudal axis. In an attempt to elucidate any metabolic changes in the ganglion due to possible alteration in its vascular supply in the displaced position, enzyme histochemical studies were undertaken on the forebrain of septally cannulated rats. A survey of hydrolases (acid and alkaline phosphatases, ATPase, cholinesterase and non-specific esterases), dehydrogenases (succinate and lactate) and diaphorases (NADH- and NADPH- tetrazolium reductases) revealed no difference in activity between the ganglia of the two sides. Cortical activity appeared to be enhanced with a rostral shift of the ganglion and decreased with a caudal shift. In the light of available histoenzymatic data on ischaemic brain damages, the present results rule out the existence of any major metabolic difference between the two basal ganglia. This underlines the extraordinary degree of functional plasticity of subcortical nuclear masses, despite considerable physical displacement.     

Cyclic AMP content of autonomic ganglia as affected by catecholamines

The relative content of cAMP was measured in the rat ganglion nodosum, lumbar ganglia of the sympathetic trunk, the main pelvic ganglion and intramural ganglia of the heart. It was observed that the basal level of cAMP in the cardiac ganglia was lower than in other ganglia. The process of stimulation of the cAMP content by noradrenaline was most pronounced in the main pelvic and lumbar ganglia, that by dopamine in the cardiac ganglia. The catecholamines failed to alter the cAMP content in the ganglion nodosum.     

扁玉螺中枢神经系统解剖及显微结构观察

对扁玉螺(Neverita didyma)中枢神经系统的大体解剖和显微结构进行了初步研究。结果表明,扁玉螺中枢神经系统包括一对口球神经节、一对脑神经节、一对侧神经节、一对足神经节及一个脏神经节。各神经节均由神经节被膜、胞体区及中央纤维网三部分组成。左右脑神经节之间和左右足神经节之间的联合以及脑-侧、脑-足和侧-足神经节之间的连索均较短。足神经节有明显的分区现象。     

Distribution of neurons in the major pelvic ganglion of the rat which supply the bladder,colon or penis

Summary In male rats a large number of the postganglionic neurons which innervate the pelvic organs are located in the major pelvic ganglion. In the present study we have identified the location within this ganglion of neurons which project to either of three pelvic organs, the penis, colon or urinary bladder. Two fluorescent retrogradely-transported dyes, Fast Blue and Fluoro-Gold, were used. For most animals one dye was injected into the cavernous space of the penis, the wall of the distal colon or the wall of the urinary bladder. In a small number of animals two organs were injected, each with a different dye. One to six weeks after injection the major pelvic ganglia were fixed in buffered formaldehyde. The distribution of fluorescent dye-labelled cells was observed in whole mounts of complete ganglia and, in most cases, also in small accessory ganglia located between the ureter and the prostate. The studies showed a unique pattern of distribution for each organ-specific group of neurons. Most of the colon neurons are located in the major pelvic ganglion near the entrance of the pelvic nerve, whereas almost all of the penis neurons are near or within the penile nerve. Bladder neurons are relatively evenly distributed throughout the ganglion. These results demonstrate a distinct topographical organization of organ-specific neurons of the major pelvic ganglion of the male rat, a phenomenon which has also been observed in other peripheral ganglia.     

大鼠脊神经节内交感神经支配的荧光组织化学与HRP示踪观察

本研究应用乙醛酸诱发儿茶酚胺（ＣＡ）荧光技术观察大鼠肾上腺素（ＮＡ）能神经在脊神经节内的分布;并应用ＨＲＰ顺、逆行追踪技术对脊神经节内ＮＡ能神经纤维的起源及其与脊神经节神经元的关系进行了探讨。荧光组织化学观察发现、有些神经节神经元胞体周围分布有带膨体的ＮＡ能神经末梢;有的紧密围绕脊神经节细胞——卫星细胞复合体。颈上交感神经节内注射霍乱毒素Ｂ亚单位结合ＨＲＰ（ＣＢ┐ＨＲＰ）,在同侧Ｃ３～６节段脊神经节内可见标记的点状纤维末梢紧邻于节细胞旁。Ｔ１１～Ｌ２节段脊神经节内注射ＨＲＰ后,在同侧椎旁交感链（Ｔ９～Ｌ１）内可见标记的交感节后神经元胞体。上述实验结果表明,交感节后神经元发出节后纤维可直接到达脊神经节内,与节细胞发生接触。本研究提示、交感神经在脊神经节水平可能参与躯体初级传入信息的调制     

Serotonin immunoreactivity of neurons in the gastropod Aplysia californica

Serotonergic neurons and axons were mapped in the central ganglia of Aplysia californica using antiserotonin antibody on intact ganglia and on serial sections. Immunoreactive axons and processes were present in all ganglia and nerves, and distinct somata were detected in all ganglia except the buccal and pleural ganglia. The cells stained included known serotonergic neurons: the giant cerebral neurons and the RB cells of the abdominal ganglion. The area of the abdominal ganglion where interneurons are located which produce facilitation during the gill withdrawal reflex was carefully examined for antiserotonin immunoreactive neurons. None were found, but two bilaterally symmetric pairs of immunoreactive axons were identified which descend from the contralateral cerebral or pedal ganglion to abdominal ganglion. Because of the continuous proximity of this pair of axons, they could be recognized and traced into the abdominal ganglion neuropil in each preparation. If serotonin is a facilitating transmitter in the abdominal ganglion, these and other antiserotonin immunoreactive axons in the pleuroabdominal connectives may be implicated in this facilitation.     

Motor program initiation and selection in crickets, with special reference to swimming and flying behavior

An air puff stimulus to the cerci of a cricket (Gryllus bimaculatus) evokes flying when it is suspended in air, while the same stimulus evokes swimming when it is placed on the water surface. After bilateral dissection of the connectives between the suboesophageal and the prothoracic ganglia or between the brain and the suboesophageal ganglion, the air puff stimulus evokes flying even when the operated cricket is placed on the water surface. A touch stimulus on the body surface of crickets placed on the water surface elicits only flying when the connectives between suboesophageal and prothoracic ganglia are dissected, while the same stimulus elicits either swimming or flying when the connectives between the brain and the suboesophageal ganglion are dissected. These results suggest that certain neurons running through the ventral nerve cords between the brain and the suboesophageal ganglion or between the suboesophageal and the prothoracic ganglia play important but different roles in the initiation and/or switching of swimming and flying. In the suboesophageal ganglion, we physiologically and morphologically identified four types of "swimming initiating neurons". Depolarization of any one of these neurons resulted in synchronized activities of paired legs with a similar temporal sequence to that observed during swimming.     

Melanogenesis in cultures of peripheral nervous tissue. II. Environmental factors determining the fate of pigment-forming cells

Spinal ganglia from 4- to 7-day [Stage 23–30; Hamburger and Hamilton (1951) J. Morphol.88, 49–92] chicken embryos were cultured in vitro to investigate the effect of various environmental conditions on cell differentiation. Culture morphology (i.e., degree of dispersion of the explanted ganglia, survival of neurons, and outgrowth of axons) was observed to depend upon several factors including: (1) the age of the explanted ganglia, (2) the presence or absence of nerve growth factor (NGF), and (3) the nature of the substratum on which the cultured tissue resides. These observations enabled us to disturb the association of neurons with the other cells in ganglion cultures and thereby modulate the differentiation of adventitious melanocytes. Thus, in medium permissive for melanogenesis, melanocytes appear when the association between neurons and small stellate nonneuronal cells in the ganglion is disrupted. This disruption is most extensive (1) when young (Stage 26–27, 5-day) ganglia are explanted on plastic substrata, in the initial absence of NGF, and (2) when cells from enzyme-dissociated ganglia are cultured on plastic substrata. In comparable media, pigment cell differentiation is not observed when the association between neurons and small stellate cells is preserved. Such associations tend to endure (1) in developmentally older (Stage 30+, 7- to 8-day) ganglia or (2) when ganglia are cultured on agar or fibroblast substrata. We conclude that loss of association between neurons and the nonneuronal cells in young ganglia is necessary for the latter to undergo melanogenesis in vitro.     

On the structure of the pulmonate osphradium

Summary The osphradium of Planorbarius consists of a blindly-ending ciliated canal, formed by an infolding of the mantle epithelium, and a basal ganglion of nerve cells which is comparable in complexity with ganglia of the central nervous system. The distribution of cell types in the osphradial epithelium is specialised so that three regions can be recognised; the ciliated, the secretory and the sensory regions. The basal sensory region of the canal epithelium consists of ciliated cells and is innervated by sensory neurones of the osphradial ganglion. The middle secretory region contains mainly of mucus-secreting cells and the epithelium adjacent to the osphradial aperture of ciliated cells and secretory cells of a second type. The sensory neurones of the osphradial ganglion are bipolar or of a modified monopolar type. Other monopolar neurones, similar to those common in the central nervous system are of non-sensory function. The osphradium of Paludina, although of typical prosobranch form, possesses ciliated pits similar to the single canal of Planorbarius, which may indicate a shared modality of receptor function. A definite function cannot be ascribed to the pulmonate osphradium based on morphological evidence alone.     

Phylogenetic significance of the ventral nerve cord in the Chrysomeloidea (coleptera: Phytophaga)

Abstract The ventral nerve cord of adult Chrysomeloidea exhibits variation in the degree of fusion of the meso-and metathoracic ganglia. similar variation occurs also in the ganglia ofthe abdominal chain, and in the single or double connectives between them. In adult Chrysomeloidea (and Curculionoidea) there never seem to be more than five separate abdominalganglia, the first two being more or less fused to the metathoracic ganglion and the lasttwo more or lessconnate; the supposed primitive condition is retained in some Cerambycidae. Trends toward the fusion of aditional abdominal ganglia appear in several differentlines in Chrysomelidae (and in Cerambycidae), and in more than one line a conditiones is reached in which only the ganglion in the third abdominal segmetn remains free. Structures possibly representing 'perisynmpathetic organs' have been observed in a few of the seventy-eight European and Indian species studied. systematic and phylogenetic conclusions are drawwn.     

The caudal ganglion of the leech,with particular reference to homologues of segmental touch receptors

The caudal ganglion of the leech, which provides sensory and motor innervation to the posterior sucker, represents the fusion of seven embryonic segmental ganglia. Although fused, each of the seven contributing ganglia (“subganglia”) of the caudal ganglion can be distinguished morphologically and functionally. The roots from each subganglion carry the axons of mechanoreceptors homologous to “touch” cells found in the segmental ganglia and the subesophageal compound ganglion. The receptive fields supplied by the touch cells of the caudal ganglion are uniquely arranged and reveal the modified segmentation of the circular posterior sucker. Extensive overlap of sensory innervation occurs between adjacent segments of the sucker, beyond the overlap characteristic of the homologous cells of body segments. It thus appears that the touch receptors of the caudal ganglion are less restricted than receptors of the segmental ganglia with regard to their territories of innervation. The caudal ganglion has additional unique properties that establish it as a distinct integrative center of the leech CNS.     

Parasympathetic control of the heart. II. A novel interganglionic intrinsic cardiac circuit mediates neural control of heart rate.

Intracardiac pathways mediating the parasympathetic control of various cardiac functions are incompletely understood. Several intracardiac ganglia have been demonstrated to potently influence cardiac rate [the sinoatrial (SA) ganglion], atrioventricular (AV) conduction (the AV ganglion), or left ventricular contractility (the cranioventricular ganglion). However, there are numerous ganglia found throughout the heart whose functions are poorly characterized. One such ganglion, the posterior atrial (PA) ganglion, is found in a fat pad on the rostral dorsal surface of the right atrium. We have investigated the potential impact of this ganglion on cardiac rate and AV conduction. We report that microinjections of a ganglionic blocker into the PA ganglion significantly attenuates the negative chronotropic effects of vagal stimulation without significantly influencing negative dromotropic effects. Because prior evidence indicates that the PA ganglion does not project to the SA node, we neuroanatomically tested the hypothesis that the PA ganglion mediates its effect on cardiac rate through an interganglionic projection to the SA ganglion. Subsequent to microinjections of the retrograde tracer fast blue into the SA ganglion, >70% of the retrogradely labeled neurons found within five intracardiac ganglia throughout the heart were observed in the PA ganglion. The neuroanatomic data further indicate that intraganglionic neuronal circuits are found within the SA ganglion. The present data support the hypothesis that two interacting cardiac centers, i.e., the SA and PA ganglia, mediate the peripheral parasympathetic control of cardiac rate. These data further support the emerging concept of an intrinsic cardiac nervous system.     

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.     

Herpes simplex virus in the vestibular ganglion and the geniculate ganglion—role of loose myelin

This study presents the first direct evidence for herpes simplex virus type 1 (HSV-1) infection in the neurons of the vestibular ganglion. Although many investigators have reported electron microscopic evidence of HSV-1 infection in sensory ganglia, HSV-1 infection in the vestibular ganglion has not been described. Vestibular ganglion neurons have a unique structure, with a loose myelin sheath instead of the satellite cell sheath that is seen in other ganglia. This loose myelin is slightly different from compact myelin which is known as too tight for HSV-1 to penetrate. The role of loose myelin in terms of HSV-1 infection is completely unknown. Therefore, in an attempt to evaluate the role of loose myelin in HSV-1 infection, we looked for HSV-1 particles, or any effects mediated by HSV-1, in the vestibular ganglion as compared with the geniculate ganglion. At the light microscopic level, some neurons with vacuolar changes were observed, mainly in the distal portion of the vestibular ganglion where the communicating branch from the geniculate ganglion enters. At the electron microscopic level, vacuoles, dilated rough endoplasmic reticulum and Golgi vesicles occupied by virus were observed in both ganglia neurons. In contrast, viral infections in Schwann and satellite cells were observed only in the geniculate ganglion, but not in the vestibular ganglion. These results suggest that loose myelin is an important barrier to HSV-1 infection, and it must play an important role in the prevention of viral spread from infected neurons to other cells.     

Tracheation of abdominal ganglia and cerci in the house cricket Acheta domesticus (Orthoptera,Gryllidae)

Patterns of tracheation in the abdominal central nervous system and the cerci of Acheta domesticus are described from whole mounts, and light and electron microscopy. The tracheal supply of the ganglia is derived from ventral longitudinal tracheal trunks which have segmental connections to the spiracels. Each abdominal ganglion is served by a single pair of tracheal trunks, except the terminal ganglion, which has two pairs. Within the ganglia, tracheoles occur principally in association with glia-rich areas of the neuropile. We suggest that the respiratory exchange may be concentrated in the cell bodies of neurons and glia. Each cercus has a tracheal supply in paralle with a large air sac which, it is suggested, serves to lighten the cercus, functions as a resonator for sound reception, or facilitates tidal flow of hemolymph and postecdysial expansion of the cercus. No tracheae run continuously between ganglia or between the terminal ganglion and the cerci, and they do not appear to have a potential role as a contact guidance pathway for cercal nerve growth.     

Considerations on the thalamostriatal system with some functional implications

The thalamostriatal projections are largely neglected in current reviews dealing with basal ganglia function. In the past few years, however, several studies have re-evaluated these projections and have postulated their implication in more complex tasks within the basal ganglia organization. In this review, we try to focus on the morphological and functional importance of this system in the basal ganglia of the rat, cat and monkey. Special attention is paid to the thalamus as an important place for interaction between the input and the output systems of the basal ganglia through the thalamostriatal projections. Thus, we stress on the overlapping thalamic territories between the thalamic projection of the output nuclei of the basal ganglia and the thalamostriatal neurons. Our experimental data support the existence of several thalamic feedback circuits within the basal ganglia functional design. Finally, some considerations are provided upon the functional significance of these thalamic feedback circuits in the overall organization of the basal ganglia in health and disease.     

Amino acid and protein metabolism in the nervous system of the praying mantid

An analysis of four ganglia of the mantid Stagmatopera biocellata (‘brain’, B; prothoracic ganglion, P; mesothoracic ganglion, M; and metathoracic ganglion, T) is presented. The four ganglia are alike in total protein contents, total free amino acids, concentration of free leucine, and concentrations of every one of 17 protein-bound amino acids. Electrophoretic separation of the proteins show almost identical curves for the four ganglia with 18 peaks at the same points of relative mobility. Thus, according to these analysis, B, P, M, and T appear to be similar masses of nervous tissue. On the other hand, they behave in different ways when the dynamic state of free leucine is studied. Both, the flux leucine from the haemolymph into the ganglia and the turnover rate of protein bound leucine differ between ganglia. Results indicate a metabolic gradient M→T→P→B of protein synthesis. A correlation between the metabolic gradient and differences in the control of motor activity and sensorial input in the ganglia is suggested. Data on total free amino acids and total protein in haemolymph are given. The probable meaning of the noticeable contrast between the constancy in values of aminoacidemia and the high variability in values of proteinemia is discussed.     

Neuronal competition determines the spatial pattern of neuropeptide expression by identified neurons of the leech.

Staining adult and embryonic leech ventral nerve cords with antibodies raised against the molluscan neuropeptides small cardioactive peptide B (SCP) and FMRFamide results in segment-specific and bilaterally asymmetric patterns of cell staining. One immunoreactive neuron, the RAS interneuron, is present in only four rostral segmental ganglia, while another, the CAS interneuron, is restricted to the four most caudal abdominal ganglia and tail. In addition to their segment-specific distributions, only one RAS or CAS cell is found in each segmental ganglion, and they alternate sides between adjacent ganglia (either L-R-L-R or R-L-R-L) with a fidelity of about 95%. This paper utilizes cell deletion techniques to investigate the determination of the asymmetric and alternating pattern of RAS and CAS neurons. We show that developmentally equivalent RAS and CAS homologs are present on both sides of the appropriate ganglia, and that within each ganglion one of the initially paired homologs loses the ability to assume the immunoreactive RAS or CAS fate 2-3 days after axonogenesis has begun. These experiments suggest that there is a competitive interaction between bilateral homologs which ensures that only one mature RAS/CAS neuron is formed per ganglion, and that contralateral RAS/CAS neurons are not required in the same or adjacent ganglia for the determination of the RAS or CAS developmental pathways. Nerve cord transections between ganglia in the CAS domain can alter the spatial pattern of CAS neuron determination, confirming that both bilateral homologs retain the ability to express neuropeptide until late embryonic stages, and suggesting that the alternating pattern of RAS/CAS cells requires communication between adjacent ganglia through the longitudinal connectives.     

The stomatogastric nervous system of the house cricket Acheta domesticus L. I. The anatomy of the system and the innervation of the gut

The distribution of the ganglia and nerves of the stomatogastric nervous system and the innervation of the extrinsic and intrinsic muscles are described. Median unpaired frontal and hypocerebral ganglia and paired ingluvial ganglia are present. The anterior pharynx is innervated by branches of the frontal nerve and by the anterior and posterior pharyngeal nerves, originating from the frontal ganglion. The posterior pharyngeal nerves are linked to nerves innervating the posterior part of the pharynx which have their origin in the hypocerebral ganglion, the anterior portion of which has previously been regarded as part of the recurrent nerve. Paired esophageal nerves run the length of the esophagus and crop between the hypocerebral and and ingluvial ganglia, innervating the muscularis by serial side branches. From each ingluvial ganglion runs an ingluvial nerve which innervates the gizzard and a cecal nerve which innervates the midgut and its ceca. At the posterior end of the midgut there is a poorly developed nerve ring. Nerves running posteriorly from this nerve ring link the stomatogastric nervous system with the proctodeal innervation from the terminal abdominal ganglion. Multipolar peripheral neurons are present on the muscularis of the whole of the foregut, rather randomly distributed on the crop and gizzard but forming fairly definite groupings at some points on the pharynx. Though of varied appearance, these cells could not be divided into discrete morphological categories. Peripheral neurons on the midgut are of different and characteristic morphology, though a few cells of the same appearance as those of the foregut occur at the midgut-hindgut boundary. Nerve fibers on the gut almost invariably terminate on the fibers of the muscularis.