Serotonin immunoreactivity in the central nervous system of the marine molluscs Pleurobranchaea californica and Tritonia diomedea

The central nervous systems of the marine molluscs Pleurobranchaea californica (Opisthobranchia: Notaspidea) and Tritonia diomedea (Opisthobranchia: Nudibranchia) were examined for serotonin-immunoreactive (5-HT-IR) neurons and processes. Bilaterally paired clusters of 5-HT-IR neuron somata were distributed similarly in ganglia of the two species. In the cerebropleural ganglion complex, these were the metacerebral giant neurons (both species), a dorsal anterior cluster (Pleurobranchaea only), a dorsal medial cluster including identified neurons of the escape swimming network (both species), and a dorsal lateral cluster in the cerebropleural ganglion (Pleurobranchaea only). A ventral anterior cluster (both species) adjoined the metacerebral giant somata at the anterior ganglion edge. Pedal ganglia had the greatest number of 5-HT-IR somata, the majority located near the roots of the pedal commissure in both species. Most 5-HT-IR neurons were on the dorsal surface of the pedal ganglia in Pleurobranchaea and were ventral in Tritonia. Neither the buccal ganglion of both species nor the visceral ganglion of Pleurobranchaea had 5-HT-IR somata. Afew asymmetrical 5-HT-IR somata were found in cerebropleural and pedal ganglia in both species, always on the left side. The clustering of 5-HT-IR neurons, their diverse axon pathways, and the known physiologic properties of their identified members are consistent with a loosely organized arousal system of serotonergic neurons whose components can be generally or differentially active in expression of diverse behaviors.     

Gonadotropin-releasing hormone receptor couples to multiple G proteins in rat gonadotrophs and in GGH3 cells: evidence from palmitoylation and overexpression of G proteins

Nicotinamide-adenine-dinucleotide-phosphate-diaphorase (NADPH-d) histochemistry has been applied in the present study to determine the distribution of putative nitric oxide (nitric oxide synthase)-producing cells during embryonic and early postembryonic development in the pond snail, Lymnaea stagnalis L., with special reference to the nervous system. The first NADPH-d-positive structures appear as early as 18% of development (E18, trochophore stage) and correspond to the pair of protonephridia. These structures later show disintegration, although after metamorphosis (E26=75%) staining of their individually spreading cells can be observed until hatching. Peripheral sensory neurons in the foot, mantle edge and lips, and their afferents projecting to the central nervous system reveal NADPH-d activity in the postmetamorphosis period (E25-E27=E60%-E80%) of embryogenesis. After hatching (P1-P3), a number of stained sensory cells appear in the pharynx and esophagus. Some NADPH-d positive neuronal perikarya occur in the pedal and pleural ganglia, and a few weakly stained cells in the cerebral and buccal ganglia of juvenile snails. At the same time, a continuous bundle of reactive fibers is formed in the neuropil both through and through around the circumesophageal ganglion ring. The localization of NADPH-d activity in the developing nervous system of Lymnaea suggests that nitric oxide participates mainly in sensory processes. However, its role in specific intraganglionic integrative events cannot be excluded following embryonic metamorphosis.     

Adaptation to changes in dietary phosphorus intake in health and in renal failure

The distribution of serotonin (5-HT)-immunoreactive elements in peripheral organs of the sea-slugs Pleurobranchaea californica and Tritonia diomedea was studied in cryostat sections. For Pleurobranchaea, 5-HT-immunoreactive (5-HT-IR) neuron cell bodies were found only in the central nervous system (CNS); 5-HT-IR cell bodies were not observed in foot, tentacles, rhinophores, oral veil, mouth, buccal mass, esophagus, gills, salivary glands, skin, reproductive system, and acidic glands, nor in peripheral tentacle and rhinophore ganglia. However, 5-HT-IR neuronal processes were widely distributed in these structures and the patterns of 5-HT-IR elements were characteristic for each particular peripheral tissue. 5-HT-IR elements were most dense in the sole of the foot and the reproductive system, followed by rhinophores, tentacles, oral veil, mouth, buccal mass, and esophagus. The sensory epithelium of rhinophores, tentacles, and mouth showed a highly structured glomerular organization of 5-HT-IR fibers, suggesting a role for 5-HT in sensory signaling. A much lower density of 5-HT-IR innervation was observed in gills, skin, salivary, and acidic glands. 5-HT-IR was observed in neuropil of tentacle and rhinophore ganglia with many transverse 5-HT-IR axons running to peripheral sensory areas. The distribution of 5-HT-IR elements in Tritonia was similar to that of Pleurobranchaea. A significant suggestion of the data is that central serotonergic neurons may modulate afferent pathways from sensory epithelia at the periphery.     

Morphology and histochemistry of the rabbit pancreatic innervation

Stimulation of extrinsic nerves markedly alters pancreatic endocrine and exocrine secretion, yet little is known of the neurochemical organization and physiologic roles of specific neural pathways within the pancreas. Here we report histochemical staining for acetylcholinesterase (AChE), NADPH-diaphorase (NADPH-d), nitric oxide synthase (NOS), and several neuropeptides to identify the neurotransmitter content of rabbit pancreatic nerves. An extensive network of AChE-positive nerve fibers was found throughout the islets, acini, ducts, ganglia, and blood vessels. All pancreatic neurons were AChE positive, two thirds were NADPH-d positive, and many were NOS positive. Ganglia in the head/neck region were connected to the duodenal myenteric plexus by AChE- and NADPH-d-positive fibers, and NADPH-d-positive pancreatic neurons appeared to send processes toward both the duodenum and pancreas. Many pancreatic neurons were vasoactive intestinal peptide (VIP) positive, and VIP nerve terminals were abundant in ganglia, acini, islets, and ducts. Pituitary adenylate cyclase-activating peptide (PACAP-38)-positive fibers also were observed within acini and passing through ganglia. Substance P (SP)-, calcitonin gene-related peptide (CGRP)-, and dopamine beta-hydroxylase (DBH)-positive fibers were abundant along blood vessels and ducts, and varicose fibers were observed in pancreatic ganglia. Fine galanin-positive fibers were also occasionally observed running with blood vessels and through ganglia. Thus the rabbit pancreas receives a dense, diverse innervation by cholinergic, adrenergic, and peptidergic nerves and cholinergic pancreatic neurons, most also containing VIP or NOS or both, appear to innervate both endocrine and exocrine tissue, and may mediate local communication between the duodenum and pancreas.     

Colocalization of nitric oxide synthase and some neurotransmitters in the intramural ganglia of the guinea pig urinary bladder

The distribution of nitrergic neurons was investigated by using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry and nitric oxide synthase (NOS) immunohistochemistry in wholemount preparations of the urinary bladder in guinea pigs. Both NADPH-d+ and NOS+ neurons were located predominantly in the bladder base. Double staining showed that 70.9% of the NADPH-d+ neurons coexpressed NOS. Acetylcholinesterase histochemistry revealed that a majority of the intramural neurons were reactive, and about half of them (51.4%) were double labelled for NOS. Tyrosine hydroxylase-positive neurons were also distributed mainly in the bladder base but in a neuronal population that was separate from the preponderant NADPH-d+ neurons. Vasoactive intestinal polypeptide immunoreactivity was also detected in the some of intramural ganglion cells, in which 21.3% of them coexpressed NADPH-d. Calcitonin gene-related peptide and substance P immunoreactivities were confined to nerve fibers, often in close association with NADPH-d+ cells or extended along the blood vessels. These results have demonstrated the colocalization of NADPH-d and NOS in the majority of intramural ganglion cells. Many of the nitrergic neurons are apparently cholinergic, indicating that they are parasympathetic postganglionic neurons, and this underscores NO as the major neuromodulator in the parasympathetic nerves in the bladder walls. The localization of vasoactive intestinal polypeptide in nitrergic neurons suggests that the peptide may complement NO for regulation of micturition reflex. The close relationship of NADPH-d-reactive intramural neurons with calcitonin gene-related peptide and substance P fibers, most probably derived from dorsal root ganglion cells, suggests that NO released from the local neurons may exert its influence on the sensory neural pathways in the urinary bladder.     

Small cardioactive peptide B increases the responsiveness of the neural system underlying prey capture reactions in the pteropod mollusc, Clione limacina

Effects of small cardioactive peptide B (SCPB) on cerebral neurons which underlie prey capture in the carnivorous pteropod mollusc, Clione limacina, were investigated. SCPB in concentrations of 10 microM and higher produced direct activation of cerebral ganglion neurons underlying extrusion of buccal cones used in prey capture. SCPB in lower concentrations, between 1 and 5 microM, did not have a noticeable effect on the membrane potentials of these neurons; however, it significantly increased their responsiveness to sensory inputs from the tactile stimulation of the head, and their ability to generate afterdischarge activity. SCPB immunoreactivity was observed in cell bodies in buccal, cerebral, pedal, and intestinal ganglia, as well as in the anterior esophagus and in buccal cones where fibers stained intensely. These electrophysiological and immunohistochemical data suggest that SCPB may have a physiological role in feeding arousal in Clione.     

Prognostic factors for disease progression in advanced Hodgkin''s disease: an analysis of patients aged under 60 years showing no progression in the first 6 months after starting primary chemotherapy

Cell and tissue concentrations of NO2- and NO3- are important indicators of nitric oxide synthase activity and crucial in the regulation of many metabolic functions, as well as in nonenzymatic nitric oxide release. We adapted the capillary electrophoresis technique to quantify NO2- and NO3- levels in single identified buccal neurons and ganglia in the opisthobranch mollusc Pleurobranchaea californica, a model system for the study of the chemistry of neuron function. Neurons were injected into a 75-microm separation capillary and the NO2- and NO3- were separated electrophoretically from other anions and detected by direct ultraviolet absorbance. The limits of detection for NO2- and NO3- were <200 fmol (<4 microM in the neurons under study). The NO2- and NO3- levels in individual neurons varied from 2 mM (NO2-) and 12 mM (NO3-) in neurons histochemically positive for NADPH-diaphorase activity down to undetectable levels in many NADPH-diaphorase-negative cells. These results affirm the correspondence of histochemical NADPH-diaphorase activity and nitric oxide synthase in molluscan neurons. NO2- was not detected in whole ganglion homogenates or in hemolymph, whereas hemolymph NO3- averaged 1.8 +/- 0.2 x 10(-3) M. Hemolymph NO3- in Pleurobranchaea was appreciably higher than values measured for the freshwater pulmonate Lymnaea stagnalis (3.2 +/- 0.2 x 10(-5) M) and for another opisthobranch, Aplysia californica (3.6 +/- 0.7 x 10(-4) M). Capillary electrophoresis methods provide utility and convenience for monitoring NO2-/NO3- levels in single cells and small amounts of tissue.     

Nitrergic innervation of the rat larynx measured by nitric oxide synthase immunohistochemistry and NADPH-diaphorase histochemistry

We evaluated the involvement of nitric oxide (NO) in the laryngeal innervation of rats using NADPH-diaphorase (NADPH-d) histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry. The findings obtained by NADPH-d histochemistry were identical with those obtained by nNOS immunohistochemistry, indicating that NADPH-d is nNOS in the laryngeal innervation system. We found NADPH-d-positive nerve fibers in every region of the larynx. In the epithelia of the mucosa, a small number of NADPH-d-positive nerve fibers were detected. The plexus of NADPH-d-positive nerve fibers was commonly found in the lamina propria, and some of these fibers were clearly associated with blood vessels. We also noted NADPH-d-positive nerve fibers in the region of laryngeal glands. Some of these fibers appeared to terminate in the glandular cells. We found NADPH-d-positive nerve fibers with varicosities in the intrinsic laryngeal muscle and free-ending nerve fibers on the muscle fiber. Motor end plate-like structures were positive for NADPH-d histochemistry. The NADPH-d-positive nerve fibers appeared to terminate at motor end plate-like structures in two of nine rats examined. A cluster of NADPH-d-positive neurons were occasionally present in the lamina propria of the laryngeal mucosa, in the connective tissue between the thyroid cartilage and intrinsic laryngeal muscle, and in the connective tissue near the cricoarytenoid joint. The present findings suggest that NO participates in the autonomic, sensory, and motor innervation of the larynx.     

Comparison of desflurane with isoflurane or propofol in spontaneously breathing ambulatory patients

The coexistence of S100beta with calcitonin gene-related peptide (CGRP), substance P (SP), somatostatin (SOM), nicotinamide adenosine dinucleotide phosphate-diaphorase (NADPH-d), and tyrosine hydroxylase (TH) was examined in the glossopharyngeal and vagal sensory ganglia. S100beta immunoreactive (-ir) neurons in the jugular and petrosal ganglia frequently colocalized CGRP- or SP-ir, whereas S100beta-ir neurons in the nodose ganglion infrequently contained CGRP- or SP-ir. No S100beta-ir neurons in the jugular and petrosal ganglia showed SOM-ir while the small number of SOM-ir neurons in the nodose ganglion colocalized S100beta-ir. Many neurons in the nodose ganglion colocalized S100beta-ir and NADPH-d activity, whereas S100beta-ir neurons in the jugular and nodose ganglia infrequently contained NADPH-d activity. S100beta- and TH-ir were frequently colocalized in nodose ganglion but not in petrosal or jugular ganglion neurons. These findings suggest relationships between S100beta and specific putative transmitters in functions of subpopulations of vagal and glossopharyngeal sensory neurons.     

Local injection of kainic acid causes widespread degeneration of NADPH-d neurons and induction of NADPH-d in neurons, endothelial cells and reactive astrocytes

Nitric oxide (NO), a diffusible gas, is a messenger molecule that mediates vascular dilatation and neural transmission. The enzyme nitric oxide synthase (NOS) present in neurons is activated by Ca2+ influx associated with activation of glutamate receptors. Cultured cortical neurons containing NOS are selectively vulnerable to injury by kainic acid (KA). However, the relationship between NOS neurons and excitotoxicity under in vivo conditions is not entirely clear. In the present study, we examined the time course and spatial distribution of changes in NOS neurons caused by an intracortical microinjection of KA in adult rats. NADPH-diaphorase (NADPH-d) histochemistry was used as a marker for NOS and the neuronal changes were correlated with changes in glial cells and endothelial cells. We demonstrated a rapid loss of NADPH-d neurons in the lesion center and degeneration of NADPH-d neurons and nerve terminals throughout ipsilateral cortex and hippocampus; the striatal neurons appeared to be unaffected. Subsequent to cortical neuronal degeneration, new NADPH-d activity appeared in proliferative reactive astrocytes and in endothelial cells at lesion periphery, and in neuronal groups at lesion periphery, in ipsilateral entorhinal cortex and bilateral hippocampus. These findings indicate that neurons expressing NADPH-d in cerebral cortex and hippocampus are selectively vulnerable to KA toxicity in vivo. The subsequent induction of NOS in neural and non-neural cells may be regarded as an adaptive response to the kainate-induced brain lesion.     

Cerebellar nitric oxide synthase is expressed within granule cell patches innervated by specific mossy fiber terminals: a developmental profile

The nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) staining technique was utilized as a marker of nitric oxide synthase (NOS) to map NOS expression in developing and adult rat cerebellum. NADPH-d-positive cells were first visualized in the cerebellar cortex at postnatal day 5 (PND5) which increased to peak levels by PND30 when they began to exhibit a patch-like organization. In order to determine the relationship of the NADPH-d staining pattern with mossy fiber innervation, mossy fiber projections were traced using cholera toxin B subunit or biocytin injected into the lateral reticular nuclei (LRtN) or pontine nuclei (PtN), respectively. Double staining revealed that the clustered mossy fiber terminals projecting from the ventrorostral LRtN and caudal PtN were well matched with NADPH-d-stained patches. This patch-like localization of NOS matched with specific mossy fiber terminals in adult cerebellum implicates these NOS patches as defining distinct anatomical zones.     

Capillary electrophoresis analysis of nitric oxide synthase related metabolites in single identified neurons

Intracellular concentrations of L-citrulline (Cit) and its metabolites are related to nitric oxide synthase (NOS) activity, an enzyme producing the intercellular messenger NO in animal tissues including the nervous system. A capillary electrophoresis system using laser-induced fluorescence detection is described, and methods are developed to monitor the levels of L-arginine (Arg), Cit, and related molecules in identified neurons of the marine slugs, Pleurobranchaea californica and Aplysia californica. The limits of detection for Arg, Cit, L-arginino-succinate, L-ornithine, and L-arginine phosphate range from 50 amol to 17 fmol (5 nM to 17 microM in the neurons under study); these detection limits are significantly lower than actual intracellular levels of the metabolites, allowing the direct assay of single cells. The levels of NOS metabolites in individual neurons varied form 6 (Arg) and 4 mM (Cit) in putative NOS-containing neurons down to < 1 microM (undetectable) levels in many putative NOS-negative cells. The Arg/Cit ratio is independent of cell volume, correlates with NADPH-diaphorase staining, and appears to be a characteristic parameter for the presence of NOS activity in identified neurons.     

An ethical responsibility for pain management

Recently, neuronal nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase has been elucidated to be the nitric oxide synthase (NOS) per se. In order to examine the existence and distribution of cerebrovascular nerve fibers containing these substances, NADPH-diaphorase histochemistry was applied to the cerebral blood vessels and the cranial ganglia known to innervate the cerebral vessels in the rat. Numerous nerve fibers with varicosities forming plexuses were observed in the circle of Willis and its branches. In addition, thick nerve bundles were seen to run along the wall of the internal ethmoidal artery. NADPH-diaphorase reaction was prominent in neurons of the sphenopalatine, otic and internal carotid ganglia. This study demonstrated, for the first time, the NADPH-diaphorase-containing nerve fibers in the cerebral vessels and ganglion cells in the parasympathetic and sensory ganglia known to innervate the cerebral vessels.     

Tetracyclines and calcified tissues

Neuronal somata in the rat kidney are very often part of ganglionated plexus and contain nitric oxide synthase (NOS). Examining serial 100 microns slices of whole kidneys, we identified three subpopulations of neuronal somata by: (a) staining for NADPH-diaphorase (NADPH-d) histochemistry followed by the demonstration of dopamine beta-hydroxylase (DBH) by immunoperoxidase, and (b) staining for DBH by immunofluorescence followed by the demonstration of NADPH-d histochemical activity. The largest subpopulation of neuronal somata displayed both DBH immunoreactivity and NADPH-d histochemical activity. The second largest group of somata showed NADPH-d activity only. A small group of neuronal somata showed only DBH immunoreactivity. The presence of catecholaminergic characteristics in NOS-containing neuronal somata is unusual and raises the question as to their origin. Their heterogeneity suggests different functions for the different subpopulations.     

Behavioral choice: neural mechanisms in Pleurobranchaea

In the marine mollusk Pleurobranchaea, it is known that feeding occurs and withdrawal from tactile stimuli is suppressed when the sensory stimuli for feeding and withdrawal are presented simultaneously. This "dominance" of feeding behavior over withdrawal behavior occurs because the central nervous network controlling feeding inhibits the central nervous network controlling withdrawal. The inhibition is mediated by a bilaterally symmetrical pair of reidentifiable feeding neurons that are members of the "corollary discharge" population in the buccal ganglion. This study supports the hypothesis that inhibitory interactions between competing motor systems are responsible for the "singleness of action" that characterizes animal behavior.     

Peripheral nervous system of the ticks, Amblyomma tuberculatum Marx and Argas radiatus Railliet (Acari: Ixodoidea)

The peripheral nervous system of an ixodid and an argasid tick include the following components: (1) paired optic, cheliceral and pedipalpal nerves and unpaired stomodeal nerve arising from the pre-esophageal portion of the central nervous system (synganglion); (2) 4 pairs of pedal nerve trunks (each with appendicular and hemal branches) and 4 major pairs of opisthosomal nerves (including the paraspiracular, genital, postlateral-myosomal, and ano-myosomal nerves); and (3) the lateral "sympathetic" plexuses formed by contributions of hemal nerves arising from pedal ganglia and from the paraspiracular nerves. The salivary glands are multiply innervated by 4 pairs of nerves. The 1st pair arise from the pedipalpal nerves, the 2nd and 3rd from the lateral sympathetic plexuses, and the 4th from the paraspiracular nerves. Portions of the integument and the majority of non-appendicular muscles are innervated by various fine nerves arising from the lateral sympathetic plexuses and from the 4 pairs of opisthosomal nerves.     

Growth hormone enhances regeneration of nitric oxide synthase-containing penile nerves after cavernous nerve neurotomy in rats

PURPOSE: As growth hormone has been reported to improve nerve regeneration, we studied the effect of rat growth hormone (GH) on the regeneration of nitric oxide synthase (NOS)-containing penile nerves and the neurons in the pelvic ganglia after unilateral cavernous nerve neurotomy in rats. MATERIALS AND METHODS: Male rats were divided into three groups: sham operation (n = 14); unilateral neurotomy of a 5 mm. segment of the cavernous nerve (n = 14) with subsequent injection of buffer solution only; and unilateral neurotomy with GH injection (n = 14). Electrostimulation of the intact cavernous nerve was performed at 1 and 3 months. Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining was used to identify NOS in penile nerve fibers of the mid-shaft segment and in neurons of the pelvic ganglia. RESULTS: One month after unilateral neurotomy, both the buffer alone and GH-treated groups showed a significant decrease in NOS-containing nerve fibers in the dorsal and intracavernosal nerves on the side of neurotomy. At 3 months, the number of NOS-containing nerve fibers in the buffer alone group did not increase, while the GH-treated group showed a significant increase. In the GH-treated group at 3 months, more NOS-positive neurons in the pelvic ganglia were found on the intact side than on the side of neurotomy (p <0.034), indicating that the regeneration derives from pelvic ganglion neurons on the intact side. Furthermore, electrostimulation in the GH-treated group revealed a greater maximal intracavernosal pressure and a shorter latency period at 3 months than in those given buffer alone. CONCLUSIONS: Our results show that GH injection significantly enhances the regeneration of NOS-containing fibers in the dorsal and intracavernosal nerves after unilateral cavernous nerve injury. We believe that GH administration may present a new and more physiologic approach to the treatment of erectile dysfunction after radical pelvic surgery.     

NADPH-diaphorase-positive ganglion cells of the rat adrenal gland: age- and sex-related changes in their number, size, and distribution

The rat adrenal gland contains ganglion cells able to synthesize nitric oxide (NO). This messenger molecule controls and modulates adrenal secretory activity and blood flow. The present study analyzed the number, size, and distribution of NO-producing adrenal neurons in adulthood and during postnatal development by means of beta-nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry. This method reliably visualizes the enzyme responsible for NO generation. The reactive neurons per adrenal gland were 350-400 in both male and female adult rats. The positive nerve cell bodies were mostly located in the medulla, few being detected within the cortex and the subcapsular region. Dual labeling with anti-microtubule-associated protein 2 antibody, specific for neuronal elements, confirmed this distribution. Anti-microtubule-associated protein 1b antibody identified a subset of NADPH-d-positive neurons, displaying different degrees of maturation according to their position within the adrenal gland. At birth, there were about 220 NADPH-d-labeled neurons per adrenal gland in both sexes. As confirmed by dual immunocytochemical labeling, their great majority was evenly distributed between the cortex and the subcapsular region, the medulla being practically devoid of stained neurons. After birth, the number of adrenal NADPH-d-positive ganglion cells displayed a strong postnatal increase and reached the adult-like distribution after 1-2 months. During the period of increase, there was a transient difference in the numbers of these cells in the two sexes. Thus we present here evidence of plasticity in the number, size, and distribution of NADPH-d-positive adrenal neurons between birth and adulthood; in addition, we describe transient sex-related differences in their number and distribution during the 2nd postnatal week, which are possibly related to the epigenetic action of gonadal hormones during this period.     

Vagal efferent and afferent innervation of the rat esophagus as demonstrated by anterograde DiI and DiA tracing: focus on myenteric ganglia

Anterograde tracing with the carbocyanine tracer DiI and the aminostyrol derivative DiA was used to selectively label fibers from the nucleus ambiguus, dorsal motor nucleus and nodose ganglion, respectively, terminating in the rat esophagus, and to compare them with the innervation of the gastric fundus in the same animals. Ambiguus neurons terminated on motor endplates distributed mainly to the ipsilateral half of the esophagus. There was no evidence of preganglionic innervation of myenteric ganglia from ambiguus neurons. Neurons of the dorsal motor nucleus supplied sparse fibers to only about 10% of enteric ganglia in the esophagus while they innervated up to 100% of myenteric ganglia in the stomach. Neurons of the nodose ganglion terminated profusely on more than 90% of myenteric ganglia of the esophagus and on about 50% of ganglia in the stomach. Afferent vagal fibers were also frequently found in smooth muscle layers starting at the esophago-gastric junction. In contrast, they were extremely rare in the striated muscle part of the esophagus. These morphological data suggest a minor influence of neurons of the dorsal motor nucleus and a prominent influence of vagal afferent terminals onto myenteric neurons in the rat esophagus.     

Histochemical characterization of NADPH-diaphorase activity in area 17 of diurnal and nocturnal primates and rodents

NADPH-diaphorase (NADPH-d) activity was studied comparatively in area 17 of four mammalian species, two primates and two rodents. Three brain hemispheres each from adult capuchin-monkeys, owl-monkeys, agoutis and guinea pigs were fixed with aldehyde fixatives by perfusion and 200 microns sections were submitted to NADPH-d histochemistry, using the indirect malic enzyme method. In all species studied the neuropil pattern of enzymes activity presented a clear layered appearance. In primates, histochemical staining was most intense in layer IVc, while in rodents the highest intensity of the neuropil reaction was in supragranular layers (II and III). Comparison of cell density in grey and white matter showed that the majority of NADPH-d-positive neurones were located in the white matter of primates but not of rodents. Since NADPH-d is a nitric oxide synthase the results are very important for comparative functional studies of neuromediators and their correlations with laminar and modular organization of area 17 of the mammalian brain.