Substance P-like immunoreactivity in the trigeminal ganglion. A fluorescence, light and electron microscope study

The trigeminal ganglion of rat and guinea pig was studied for the presence of immunoreactive substance-P using fluorescence, light and electronmicroscopy. In untreated animals substance P containing cells, with a diameter of 15 to 50 micron, were distributed throughout the ganglion and comprised 10-30% of all ganglion cells. Colchicine, injected intraventricularly to inhibit intra-axonal transport, had no effect on the number of substance P cells; but when the drug was injected directly into the posterior root of the ganglion, the proportion of these cells increased to as much as 50%. In the electron microscope, immunoreactive substance-P was confined to ganglion cells classified as B type according to the arrangement of subcellular organelles, and to unmyelinated nerve fibers. Subcellularly the immunoreactivity appeared in cytoplasmic vesicles, as well as dispersed in the nerve fibers and the perikarya of neurons. The great number of substance P immunoreactive ganglion cells suggests that they do not comprise a well defined subpopulation of the B-cells. However, the immunoreactivity was restricted to a distinct ultrastructural type of neurons with unmyelinated nerve fibers, suggesting that they also may share some distinct functions.     

Neuropeptide distribution in the cervico-thoracic paravertebral ganglia of the cat with particular reference to calcitonin gene-related peptide immunoreactivity

Summary Paraffin sections of cervical and upper thoracic paravertebral ganglia of the cat were investigated by immunohistochemistry using antisera directed against calcitonin gene-related peptide (CGRP). The relationships of CGRP-immunoreactive structures to those exhibiting immunoreactivity to antisera against other regulatory peptides and dopamine--hydroxylase (DBH), respectively, were studied in consecutive sections. Singly scattered CGRP-immunoreactive neuronal perikarya were observed in the superior and middle cervical ganglia as well as in the stellate ganglion. These neurons also displayed immunoreactivity to vasoactive intestinal polypeptide (VIP), and some additionally exhibited faint substance-P immunoreactivity. DBH- and neuropeptide Y-immunoreactive ganglion cells were not identical with CGRP-immunoreactive neuronal cell bodies.According to the immunoreactive properties of varicosities, which abut on CGRP/VIP-immunoreactive perikarya, three types of CGRP/VIP-immunoreactive ganglion cells could be distinguished: (1) CGRP/VIP-immunoreactive neurons being surrounded by somatostatin-immunoreactive nerve fibers, (2) neurons being approached by both DBH- and met-enkephalin-immunoreactive varicosities, and (3) neurons receiving both DBH- and neurotensin-immunoreactive fibers. The stellate and upper thoracic ganglia harbored clusters of intensely VIP-immunoreactive somata, which lacked CGRP-immunoreactivity. Fine somatostatin-immunoreactive and coarse CGRP-immunoreactive fibers were distributed within these clusters, whereas patches of neurotensin-immunoreactive fibers were complementarily arranged. At all segmental levels investigated, a few postganglionic neurons were approached by both CGRP-immunoreactive and substance P-immunoreactive varicosities, but lacked a VIP-immunoreactive innervation. Therefore, CGRP/substance P-immunoreactive fiber baskets appeared rather to be of extraganglionic origin than to emerge from intraganglionic CGRP/VIP/SP neurons. CGRP-immunoreactive cell bodies or fibers were absent in clusters of small paraganglionic cells, but some of the solitary paraganglionic cells displayed CGRP-immunoreactivity. Our findings establish the presence of CGRP-immunoreactivity in a population of sympathetic neurons in the cat. A highly differentiated, segment-dependent organizational pattern of neuropeptides in cervico-thoracic paravertebral ganglia was demonstrated.Supported by Deutsche Forschungsgemeinschaft grant He 919/6-2     

Light and electron microscopic localization of substance P-like immunoreactivity in the cerebral ganglion of locust with a monoclonal antibody

Summary The occurrence of substance P-like immunoreactivity was studied in the locust brain at light and electron microscopic level using monoclonal IgG fraction to substance P. Small immunoreactive perikarya have been found beside the medial neurosecretory cells in horizontal brain sections. Widespread immunoreactivity was also observed in the protocerebral neuropil notably in the central body and bordering on the corpora pedunculata. The reaction endproduct appeared as fine, more or less round particles in the central body, and as coarse varicosities and wavy fibres bordering the peduncles. The roundish particles probably represent nerve terminals, while the wavy fibers correspond to neural processes. In the vicinity of the lobe immunoreactivity was not observed. Electron microscopically, a number of immunoreactive terminals were found in the protocerebral neuropil. The reaction endproduct was accumulated mostly in large dense core granules/average diameter 80 nm/however reaction endproduct was also observed on the external surface membranes of clear vesicles and mitochondria. Our results suggest the widespread occurrence of a substance-P immunoreactive neuropeptide in the cerebral ganglia of the migratory locust.     

Substance P-like immunoreactive trigeminal ganglion cells supplying the cornea

Summary Trigeminal ganglion cells supplying the cornea were traced with intra-axonally transported horseradish peroxidase and, subsequently studied for the presence of substance P-like immunoreactivity. Approximately 0%–30% of trigeminal ganglion cells contained immunoreactive substance P. These cells were of a small size (15–50 m in diameter) and were distributed throughout the ganglion. The ganglion cells supplying the cornea were of a relatively small size as well but were confined to the anteromedial part of the ganglion. Some of these cells were found to contain immunoreactive substance P.     

Substance P-like immunoreactivity in the parietal eye visual system of the lizard Uta stansburiana

Summary We examined the parietal eye visual system of the iguanid lizard Uta stansburiana for the presence of substance P-like immunoreactivity by use of both immunofluorescence and peroxidase-antiperoxidase techniques. In the parietal eye no substance P-containing somata were found; however, its plexiform layer contained small (ca. 1 m diam) immunoreactive fibers. These fibers apparently originate outside the parietal eye. Immunoreactive fibers also were found in the parietal nerve, the dorsal sac, and the leptomeninx of the pineal gland. No labeled somata were observed in any of these regions in either normal or colchicine treated animals. Previously we demonstrated that a system of centrifugal fibers to the parietal eye originates from neurons in the dorsal sac (Engbretson et al. 1981). The apparent absence of substance P-containing neurons in the dorsal sac suggests that the substance P-containing fibers in the parietal eye are not the previously observed centrifugal fibers. The source of the substance P-containing fibers in the parietal eye is unknown. The pars dorsolateralis of the left medial habenular nucleus receives a dense substance P-positive projection. No such projection was seen in the right habenula. Simultaneous visualization of the terminals of ganglion cells of the parietal eye (labeled with orthograde intraaxonally transported horseradish peroxidase) and substance P-like immunofluorescence showed that the locus of habenular immunoreactivity is distinct from the projection field of the parietal eye. Thus the substance P-positive terminals in the habenula do not originate in the parietal eye. Transection of the parietal nerve confirmed this conclusion.     

P物质、脑啡肽在豚鼠耳蜗的分布——免疫组织化学观察

本研究应用免疫组织化学方法系统地观察了P物质(SP)、亮氨酸脑啡肽(L-ENK)在豚鼠耳蜗的分布以及SP、L-ENK免疫反应阳性神经纤维与Corti's器毛细胞之间的关系,结果表明:SP的免疫反应活性(SP-IR)存在于耳蜗螺旋神经节的部分神经细胞及传入神经纤维中,在Corti's器的毛细胞下方亦可见SP免疫反应阳性纤维;L-ENK的免疫反应活性(ENK-IR)存在于耳蜗的传出神经纤维中。节内螺旋束、内螺旋束、隧道螺旋束、横贯纤维均含有大量的L-ENK免疫反应阳性纤维,Cort's器中的L-ENK免疫反应阳性终末与毛细胞之间具有密切接触,由此提示,SP可能为听觉初级传入神经递质之一;L-ENK作为传出神经递质或调质对听觉传入起调控作用。     

Projection pathways,co-existence of peptides and synaptic organization of nerve fibers in the inferior mesenteric ganglion of the guinea-pig

Summary The presence of immunoreactive enkephalin, dynorphin, vasoactive intestinal polypeptide, cholecystokinin, substance P and neuropeptide Y in nerve fibers that project to the guinea-pig inferior mesenteric ganglion was analysed, after different denervation and ligation procedures. A quantitative analysis demonstrates that enkephalin- and substance P fibers reach the ganglion mainly via lumbar splanchnic and partly via intermesenteric nerves. Dynorphin-, vasoactive intestinal polypeptide- and cholecystokinin fibers reach the ganglion mainly via colonic and partly via hypogastric or intermesenteric nerves. Neuropeptide Y fibers enter via intermesenteric, lumbar splanchnic and hypogastric nerves and pass through the ganglion. Analysis of serial 0.5 m sections tends to confirm co-existence: of dynorphin, vasoactive intestinal polypeptide and cholecystokinin in fibers projecting from the colon; of dynorphin with substance P in the lumbar splanchnic nerves; and of neuropeptide Y with substance P in the hypogastric and colonic fibers. Synaptic contacts, predominantly axodendritic, onto the ganglion cells from enkephalin-, vasoactive intestinal polypeptide-, and substance P-containing terminals were revealed by electron microscopy. Enkephalin-immunoreactive axon varicosities are filled with small, clear vesicles with a few large, cored vesicles and form asymmetric synapses; dynorphin-, vasoactive intestinal polypeptide- and cholecystokinin-immunoreactive axon varicosities are rich in large, dense-cored vesicles and form symmetric synapses.     

Origins of nerve fibers containing nitric oxide synthase in the rat celiac-superior mesenteric ganglion

The origin of nitric oxide synthase-containing nerve fibers in rat celiac-superior mesenteric ganglion was examined using retrograde tracing techniques combined with the immunofluorescence method. Fluoro-Gold was injected into the celiac-superior mesenteric ganglion. Neuronal cell bodies retrogradely labeled with Fluoro-Gold in the thoracic spinal cord, the dorsal root ganglia at the thoracic level, the nodose ganglion, and the intestine from the duodenum to the proximal colon were examined for nitric oxide synthase immunoreactivity. About 60% of sympathetic preganglionic neurons in the intermediolateral nucleus projecting to the celiac-superior mesenteric ganglion were immunoreactive for nitric oxide synthase, as were approximately 27% of nodose ganglion neurons and about 65% of dorsal root ganglion neurons projecting to the cceliac-superior mesenteric ganglion. Neurons projecting to the celiac-superior mesenteric ganglion were found in the myenteric plexus of the small and large intestine. In the proximal colon, about 23% of such neurons were immunoreactive for nitric oxide synthase. However, in the small intestine, no immunoreactivity was found in these neurons.     

Substance P-like immunoreactivity in adrenal chromaffin cells and intra-adrenal nerve fibers of rats

The present peroxidase-antiperoxidase immunohistochemical study demonstrated a relatively small number of cells with substance P(SP)-like immunoreactivity in the adrenal medulla of rats. These cells were found alone or in small groups, were polygonal in shape and lacked long cytoplasmic processes. At immunoelectron microscopy, the immunoreactive cells were characterized by abundant granular vesicles, and the immunoreactive material was confined to the round core of the vesicles. Thus, it is suggested that SP co-exists with catecholamines in a population of chromaffin cells of the rat adrenal medulla. In addition a few SP-immunoreactive nerve fibers with varicosities were found in the adrenal medulla of rats. They extended between small clusters of chromaffin cells and had their dot-like terminals around and within the cell clusters. The SP-immunoreactive nerve fibers were characterized by the presence of abundant small clear vesicles mixed with a few large granular vesicles; the immunoreactivity appeared in the latter, but was also perfused throughout the entire axoplasm. The nerve fibers formed synapses on nonimmunoreactive chromaffin cells. Judging from the presence of bundles of SP-immunoreactive nerve fibers penetrating the adrenal capsule and cortex as well as the absence of SP-immunoreactive ganglion cells in the medulla, the intramedullary SP-immunoreactive nerve fibers seem to be extrinsic in origin.     

The origin and possible significance of substance P immunoreactive networks in the prevertebral ganglia and related structures in the guinea-pig

The distribution and origin of substance P immunoreactive nerve elements have been studied in the guinea-pig prevertebral ganglia by the indirect immunohistochemical technique, using a monoclonal antibody to substance P. Non-varicose substance P immunoreactive nerve fibres enter or leave the ganglia in all nerves associated with them, traversing the ganglia in larger or smaller bundles. Networks, mainly single-stranded, of varicose substance P immunoreactive nerve fibres also permeate the ganglia, forming a loose meshwork among the neurons. Similar networks are present in the lumbar paravertebral ganglia. In all these ganglia, neuronal somata do not in general show substance P immunoreactivity. The various nerves connected with the inferior mesenteric ganglion have been cut, in single categories and in various combinations, and the ganglion examined, after intervals of up to six days. Cutting the colonic or hypogastric nerves, which connect the ganglion with the hindgut and pelvic organs, leads to accumulation of substance P immunoreactive material in their ganglionic stumps, extending retrogradely to intraganglionic non-varicose fibres traceable through into the intermesenteric and lumbar splanchnic nerves. There is some local depletion of intraganglionic varicose networks. Cutting the intermesenteric nerve, which connects the coeliac-superior mesenteric ganglion complex with the ganglion, leads to accumulation of substance P immunoreactive material in its cranial stump and depletion of its distal stump; a minimal depletion is detectable in the inferior mesenteric ganglion itself. Cutting the lumbar splanchnic nerves, which connect the ganglion with the upper lumbar spinal cord and dorsal root ganglia, leads to accumulation of substance P immunoreactive material in their proximal stumps and total depletion of their distal, ganglionic stumps; in the ganglion there is subtotal loss of non-varicose substance P immunoreactive fibres and of varicose nerve networks, and the few surviving non-varicose fibres are traceable across the ganglion from the intermesenteric nerve to the colonic and hypogastric nerves. Cutting the intermesenteric and lumbar splanchnic nerves virtually abolishes substance P immunoreactive elements from the ganglion within three days postoperatively. It is concluded that these arise centrally to the ganglion.(ABSTRACT TRUNCATED AT 400 WORDS)     

Calcitonin gene-related peptide-like immunoreactivity in nerve fibers in the human skin. Relation to fibers containing substance P-, somatostatin- and vasocactive intestinalpolypeptide-like immunoreactivity

Calcitonin gene-related peptide-like immunoreactivity was demonstrated in in sensory nerve fibers in the epidermis and dermis as free nerve endings and around blood vessels and hair follicles of the human finger pad and arm skin. The vast majority of the calcitonin gene-related immunoreactive fibers was shown to display also substance P-like immunoreactivity and a few fibers in the dermis were somatostatin positive. No fibers displaying both substance P and somatostatin-like immunoreactivity were found but a few substance P immunoreactive fibers in the dermis-epidermis region were found to contain also vasointestinal polypeptide-like immunoreactivity. In the sweat glands, abundant calcitonin gene-related peptide positive, but substance P negative, fibers were observed with a similar distribution pattern as the vasoactive intestinal polypeptide immunoreactive fibers and these fibers were suggested to be of sympathetic origin.     

Substance P-like immunoreactivity in adrenal chromaffin cells and intra-adrenal nerve fibers of rats

Summary The present peroxidase-antiperoxidase immunohistochemical study demonstrated a relatively small number of cells with substance P(SP)-like immunoreactivity in the adrenal medulla of rats. These cells were found alone or in small groups, were polygonal in shape and lacked long cytoplasmic processes. At immunoelectron microscopy, the immunoreactive cells were characterized by abundant granular vesicles, and the immunoreactive material was confined to the round core of the vesicles. Thus, it is suggested that SP co-exists with catecholamines in a population of chromaffin cells of the rat adrenal medulla. In addition a few SP-immunoreactive nerve fibers with varicosities were found in the adrenal medulla of rats. They extended between small clusters of chromaffin cells and had their dotlike terminals around and within the cell clusters. The SP-immunoreactive nerve fibers were characterized by the presence of abundant small clear vesicles mixed with a few large granular vesicles; the immunoreactivity appeared in the latter, but was also perfused throughout the entire axoplasm. The nerve fibers formed synapses on nonimmunoreactive chromaffin cells. Judging from the presence of bundles of SP-immunoreactive nerve fibers penetrating the adrenal capsule and cortex as well as the absence of SP-immunoreactive ganglion cells in the medulla, the intramedullary SP-immunoreactive nerve fibers seem to be extrinsic in origin.     

Calcitonin gene-related peptide-like immunoreactivity in nerve fibers in the human skin

Summary Calcitonin gene-related peptide-like immunoreactivity was demonstrated in in sensory nerve fibers in the epidermis and dermis as free nerve endings and around blood vessels and hair follicles of the human finger pad and arm skin. The vast majority of the calcitonin generelated immunoreactive fibers was shown to display also substance P-like immunoreactivity and a few fibers in the dermis were somatostatin positive. No fibers displaying both substance P and somatostatin-like immunoreactivity were found but a few substance P immunoreactive fibers in the dermis-epidermis region were found to contain also vasointestinal polypeptide-like immunoreactivity. In the sweat glands, abundant calcitonin gene-related peptide positive, but substance P negative, fibers were observed with a similar distribution pattern as the vasoactive intestinal polypeptide immunoreactive fibers and these fibers were suggested to be of sympathetic origin.     

Calcitonin gene-related peptide immunoreactivity in the biliary pathway and liver of the guinea-pig: distribution and colocalization with substance P

Summary Calcitonin gene-related peptide immunoreactivity was localized immunohistochemically in nerve fibers innervating the biliary pathway and liver of the guinea-pig. Immunoreactive fibers are present in all layers of the gallbladder and biliary tract and are particularly numerous around blood vessels. In the liver, immunoreactive processes are usually restricted to the interlobular space and porta hepatis, and only a few, very thin, beaded processes were observed in the hepatic parenchyma. A rich innervation is also associated with the vena portae. Positive ganglion cell bodies were not visualized within the ganglionated plexus of the biliary system, whereas they were found in the myenteric and submucosal plexus in the cranial portion of the duodenum corresponding to the sphincter of Oddi. The vast majority, if not all, of calcitonin gene-related peptide-immunoreactive fibers contain substance P immunoreactivity; however, there are some substance P-containing fibers lacking calcitonin gene-related peptide immunoreactivity. The lack of co-occurrence of calcitonin gene-related peptide and substance P immunoreactivities in intrinsic ganglion cells suggests that these two peptides are coexpressed in the extrinsic component of the innervation of the hepatobiliary system.     

Localisation of substance P-like immunoreactivity in the ciliary ganglia of monkey (Macaca fascicularis) and cat: a light- and electron-microscopic study

The present study describes substance P-like immunoreactivity in the ciliary ganglia of monkey (Macaca fascicularis) and cat. About 60% of neurons in the monkey ciliary ganglion and 40% in the cat ciliary ganglion were substance P-like immunoreactive, ranging from faint to moderate staining. Substance P-like immunoreactivity was located in cell bodies, dendritic profiles and axons. In the monkey, substance P-like immunoreactive pericellular arborisations were associated with about 0.5%–3% of the ganglion cells, which were either negatively, faintly or moderately stained. An electron-microscopic study demonstrated the presence of either substance P-like immunoreactive positive or negative axon terminals synapsing or closely associated with positive dendritic profiles in both the monkey and cat ciliary ganglia. The results suggest that substance P plays an important role in the ciliary ganglion, perhaps as a modulator or transmitter.     

Localization of FMRFamide- and ACEP-1-like immunoreactivities in the nervous system and heart of a pulmonate mollusc,Achatina fulica

Immunohistochemical localization of two neuropeptides possibly involved in the regulation of cardiac activity in a pulmonate mollusc, Achatina fulica Férussac, was studied. On the ventral surface of the right cerebral ganglion, more than 50 neurons with diameters of 30–50 m showed immunoreactivity to the antiserum of the neuropeptide FMRFamide. Many were also immunoreactive to an antiserum raised against Achatina cardio-excitatory peptide-1 (ACEP-1). Although FMRFamidelike immunoreactive neurons occurred in all components of the subesophageal ganglia, identifiable ACEP-1-like immunoreactive neurons were located only in the visceral ganglion and the right parietal ganglion. In the heart, FMRFamide- and ACEP-1-like immunoreactive fibers were restricted to the atrium and the aortic end of the ventricle, consistent with morphological observations of cardiac innervation. The present results suggest that FMRFamide-and ACEP-1-like peptides are involved in regulating the heart beat of this snail.     

Immunocytochemical study of tyrosine hydroxylase and dopamine β-hydroxylase immunoreactivities in the rat pancreas

An immunohistochemical and immunoelectron microscopic study was used to demonstrate tyrosine hydroxylase (TH) and dopamine -hydroxylase (DBH) immunoreactivities in the rat pancreas. Small TH immunoreactive cells were found in close contact with large TH immunonegative ganglion cells among the exocrine glands and were occasionally found in some islets. Some of these TH immunoreactive cells were also DBH immunopositive. The immunoreaction product was seen diffusely in the cytoplasm and in the granule cores of TH immunoreactive cells. All intra-pancreatic ganglion cells were immunoreactive for DBH, but not for TH. The TH immunoreactive cells were identified as small intensely fluorescent (SIF) cells due to their localization and morphological characteristics and showed no insulin, glucagon, somatostatin or pancreatic polypeptide immunoreactivities. These results indicate that SIF cells may release dopamine or noradrenaline to adequate stimuli while the intra-pancreatic ganglion cells with only DBH may not synthesize catecholamines in a normal biosynthetic pathway. TH immunoreactive nerve bundles without varicosities and fibers with varicosities, associated or unassociated with blood vessels, were found in both the exocrine and endocrine pancreas. Close apposition of TH immunoreactive nerve fibers to the smooth muscle and endothelial cells of the blood vessels was observed. A close apposition between TH immunoreactive nerve fibers and exocrine acinar cells and islet endocrine cells was sometimes found in the pancreas. The immunoreaction product was seen diffusely in the axoplasm and in the granular vesicles of the immunoreactive nerve fibers. Since no TH immunoreactive ganglion cells were present in the rat pancreas, the present study suggests that noradrenergic nerve fibers in the pancreas may be extrinsic in origin, and may exert an effect on the regulation of blood flow and on the secretory acitivity of the acinar cells, duct cells and endocrine cells.     

Production and characterization of a monoclonal antibody against human calcitonin gene-related peptide (CGRP) and its immunohistochemical application to salivary glands

Summary A monoclonal antibody (mAb), 129CD8 was raised against a C-terminal fragment (aa28–37) of -human calcitonin gene-related peptide (CGRP) coupled to bovine serum albumin. The specificity of the monoclonal antibody 129CD8 was corroborated by dot immunobinding experiments, enzyme-linked immunoassay and immunostaining of tissue sections. In vitro studies showed that the mAb 129CD8 readily recognized the fragment 28–37 of -human CGRP and to a slightly lesser degree whole -human CGRP and the fragments containing the C-terminal part of the molecule. The mAb 129CD8 also recognized the -human CGRP but not the -rat CGRP. The mAb 129CD8 did not react with substance P, katacalcin, calcitonin, amylin or fragments of -human CGRP lacking the C-terminal part of the molecule.Immunocytochemical staining was performed on human skin, guinea-pig thyroid and salivary glands and the trigeminal ganglion, and rat thyroid gland. Our findings demonstrate, in keeping with previous studies, that in human skin, nerve fibres containing CGRP immunoreactivity are found in both epidermis and dermis. In accordance with previous investigators, the Merkel cells were immunoreactive for CGRP. In the guinea-pig and rat thyroid gland CGRP immunoreactivity was localized in the C-cells. The distribution of CGRP immunoreactivity in the guinea-pig salivary glands is different from that previously reported for rat salivary glands. In the guinea-pig trigeminal ganglion, CGRP immunoreactivity was localized mainly in small-sized neurons and fibres traversing the ganglion. Double staining with substance P performed on guinea-pig trigeminal ganglion revealed four types of sensory neurons, those containing both peptides, those containing only substance P or CGRP and those lacking both peptides. Guinea-pig parotid gland, but not the submandibular or sublingual glands, contained periacinar fibres exhibiting both immunoreactivities. Substance P-positive, CGRP-positive fibres were also seen around parotid and submandibular, but not around sublingual, gland ducts. All glands received perivascular innervation showing immunoreactivities for both peptides. The present results support the idea that in the peripheral nervous system only a subpopulation of sensory neurons contains both substance P and CGRP. Consequently, colocalization of substance P and CGRP indicates a sensory nerve, while those containing either substance P or CGRP may be sensory or parasympathetic.     

Immunocytochemistry of GABA and glutamic acid decarboxylase in the thoracic ganglion of the crab Eriphia spinifrons

We have used specific antisera against protein-conjugated -aminobutyric acid (GABA) and rat-brain glutamic acid decarboxylase (GAD) in immunocytochemical preparations to study the distribution of putatively GABAergic neurons in the fused thoracic ganglion of the crab Eriphia spinifrons. In the thoracic neuromeres, about 2000 neurons with somata arranged in clusters or located singly in the cell cortex exhibited both GABA-like and GAD-like immunoreactivity. In addition, more than a hundred cells showed only GABA-like immunoreactivity. Fibrous immunoreactive staining to GAD and GABA was distributed throughout the neuropil of the thoracic ganglion, and several fiber tracts contained immunoreactive processes. Sets of serially homologous neurons exhibited GABA-like and GAD-like immunoreactivity in the thoracic neuromeres. Especially prominent were one medial and four ventro-lateral clusters of somata, together with thirteen individually recognized cells in each neuromere. Six of these cells in the ventro-medial cell cortex may be the somata of inhibitory motoneurons. The leg nerves contained three immunoreactive fibers, corresponding to the previously described common inhibitory motoneuron and the two specific inhibitors. The results present further evidence for GABA being the neurotransmitter of all inhibitory leg motorneurons, and suggest its presence and role as a neurotransmitter in a considerable number of interneurons in the thoracic ganglion of the crab.     

Ganglion cells immunoreactive for catecholamine-synthesizing enzymes,neuropeptide Y and vasoactive intestinal polypeptide in the rat adrenal gland

Immunohistochemistry has been used to demonstrate tyrosine hydroxylase (TH), dopamine--hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) immunoreactivities, and acetylcholinesterase (AChE) activity was demonstrated in rat adrenal glands. The TH, DBH, NPY and VIP immunoreactivities and AChE activity were observed in both the large ganglion cells and the small chromaffin cells whereas PNMT immunoreactivity was found only in chromaffin cells, and not in ganglion cells. Most intraadrenal ganglion cells showed NPY immunoreactivity and a few were VIP immunoreactive. Numerous NPY-immunoreactive ganglion cells were also immunoreactive for TH and DBH; these cells were localized as single cells or groups of several cells in the adrenal cortex and medulla. Use of serial sections, or double and triple staining techniques, showed that all TH- and DBH-immunoreactive ganglion cells also showed NPY immunoreactivity, whereas some NPY-immunoreactive ganglion cells were TH and DBH immunonegative. NPY-immunoreactive ganglion cells showed no VIP immunoreactivity. AChE activity was seen in VIP-immunopositive and VIP-immunonegative ganglion cells. These results suggest that ganglion cells containing noradrenaline and NPY, or NPY only, or VIP and acetylcholine occur in the rat adrenal gland; they may project within the adrenal gland or to other target organs. TH, DBH, NPY, and VIP were colocalized in numerous immunoreactive nerve fibres, which were distributed in the superficial adrenal cortex, while TH-, DBH- and NPY-immunoreactive ganglion cells and nerve fibres were different from VIP-immunoreactive ganglion cells and nerve fibres in the medulla. This suggests that the immunoreactive nerve fibres in the superficial cortex may be mainly extrinsic in origin and may be different from those in the medulla.