Changes of calbindin D-28k immunoreactivity in the hippocampus after adrenalectomy in the seizure sensitive gerbil

Calbindin D-28k (CB), a calcium-binding protein, containing neurons in the hippocampus plays an important role in hippocampal excitability in epilepsy. In the present study, we investigated changes of CB immunoreactivity after adrenalectomy (ADX) in the hippocampus and dentate gyrus of the seizure sensitive gerbil, which is susceptible to seizure to identify roles of CB in epileptogenesis. The changes of the CB immunoreactivity after ADX were significant in the hippocampal CA1 region. By 24 h after ADX, CB-immunoreactive CA1 pyramidal cells and CB immunoreactivity increased. At this time, well-stained dendrites projected to the stratum radiatum. Thereafter, the CB immunoreactivity decreased time dependently by 96 h after ADX. In the dentate gyrus, the changes of CB-immunoreactive neurons were mainly observed in the granule cell layer. The number and immunoreactivity of CB-immunoreactive neurons was high at 24 h after ADX, thereafter, those decreased by 96 h after ADX. These results suggest that glucocorticoid has an important role in modulating the seizure activity and CB serves an inhibitory function, which regulates the seizure activity and output signals from the hippocampus.     

Corticotropin-releasing factor immunoreactivity increases in the cerebellar climbing fibers in the novel ataxic mutant mouse, pogo

The ataxic pogo mouse (pogo/pogo) is a novel neurological mutant, which was derived as an inbred strain (KJR/MsKist) from a Korean wild mouse. The pathological manifestations include a difficulty in maintaining a normal posture, the failure of inter-limb coordination and an inability to walk straight. In this study, we examined the distribution of corticotropin-releasing factor (CRF) immunoreactive cerebellar climbing fibres and their projections to tyrosine hydroxylase (TH) immunoreactive Purkinje cells in the cerebellum of the pogo mutant mouse using immunohistochemistry. In the pogo/pogo mouse, a subset of climbing fibres was stained more intensely for CRF than in the control. Moreover, ataxic pogo mouse, neurons of the inferior olivary nucleus projecting climbing fibres were also more intensely stained for CRF than in the control. In the pogo/pogo mouse, TH immunoreactivity was located in the Purkinje cells, whereas no TH expression was found in the control. Double immunostaining for CRF and TH in the pogo/pogo cerebellum revealed that the distribution of TH-immunoreactive Purkinje cells corresponded to terminal fields of CRF-immunoreactive climbing fibres but not to the CRF-immunoreactive mossy fibres. Therefore, we suggest that an increase of CRF level may alter the function of targeted Purkinje cells and that it is related to the ataxic phenotype in the pogo mutant mouse.     

Differential expression of neurofilament 200-like immunoreactivity in the main olfactory and vomeronasal systems of the Japanese newt, Cynops pyrrhogaster

Expression of neurofilament 200 (NF200)-like immunoreactivity was examined in the main olfactory system and the vomeronasal system of the Japanese newt, Cynops pyrrhogaster, using anti-porcine NF200 monoclonal antibody (clone N52) to investigate the differences in phenotypical characteristics between these systems. The entire nasal cavity was a flattened single chamber consisting of the main nasal chamber (MNC) and the lateral nasal sinus (LNS) communicating with each other. The olfactory epithelium (OE) was present in the MNC, and the vomeronasal epithelium (VNE) was in the LNS. The OE possessed only a small number of NF200-like immunoreactive receptor neurons. The olfactory nerve and the olfactory nerve layer of the main olfactory bulb also contained a small number of NF200-like immunoreactive axons. In contrast, the VNE possessed many NF200-like immunoreactive receptor neurons. The vomeronasal nerve and the vomeronasal nerve layer of the accessory olfactory bulb contained many NF200-like immunoreactive axons. These findings in the Japanese newt indicate that NF200-like immunoreactive receptor neurons constitute a major subpopulation in the VNE and a minor subpopulation in the OE. In addition, NF200-like immunoreactivity seems to be a useful marker to distinguish the vomeronasal system from the other nervous systems including the main olfactory system in the Japanese newt. The localization of a few NF200-like immunoreactive receptor neurons in the OE might indicate that pheromone-sensitive receptor neurons are intermingled in the OE of the Japanese newt.     

Stimulation of Dopamine D1 Receptors Increases Activity of Periventricular Somatostatin Neurons and Suppresses Concentrations of Growth Hormone

The selective dopamine D₁ receptor agonist, SKF38393, stimulates release of somatostatin (SS) from perifused bovine hypothalamic slices. Therefore, we hypothesized that SKF38393 activates SS neurons, which, via release of SS, would suppress concentrations of growth hormone (GH) in serum in calves. Our objectives were to determine whether SKF38393: (1) increases the percent of immunoreactive c-Fos protein and Fos-related antigens (Fos/FRA) detected in somatostatin neurons in periventricular (PeVN) and arcuate (ARC) hypothalamic nuclei; (2) reduces concentrations of GH in serum; (3) suppresses growth hormone-releasing hormone (GHRH)-induced release of GH. Meal-fed steers were used to perform these objectives because a synchronous pulse of GH occurs 1–2 hr before feeding in steers allowed access to feed for 2 hr each day. In Experiment 1, two groups of four Holstein steers were injected s.c. with either vehicle (sterile water) or SKF38393 (5 mg/kg BW). Steers were injected i.v. with a lethal dose of sodium pentobarbital 100 min later and their brains were fixed with 4% paraformaldehyde. Dual-label immunohistochemistry was performed on 40 μm free-floating sections using antiserum to SS and to Fos/FRA on sections containing PeVN and ARC nuclei. More SS neurons were detected in the PeVN than in the ARC. The percent of SS neurons with immunoreactive Fos/FRA present was 2.9-fold higher in SKF38393-treated compared with vehicle-injected steers in the PeVN, but was unchanged in the ARC. In Experiment 2, eight Holstein steers were injected s.c. with either vehicle (sterile water) or SKF38393 (5 mg/kg BW) 140 min before meal-feeding. In contrast to controls, concentrations of GH in serum of SKF38393-treated steers did not increase during the 140 min before meal-feeding. In Experiment 3, eight Holstein steers were injected s.c. with either vehicle (sterile water) or SKF38393 (5 mg/kg BW), then 100 min later, each steer was injected i.v. with [Leu²⁷, Hse⁴⁵] bGHRH^1–45 lactone (0.2 μg/kg BW). Bovine GHRH stimulated release of GH into serum in both groups, but concentrations of GH were lower in SKF38393-treated steers. These results show that stimulation of D₁ receptors selectively increases activity of SS neurons in the PeVN, and this increased activity is associated with suppressed basal- and GHRH-induced release of GH in serum of meal-fed steers.     

Microtubule associated protein 2 and choline acetyltransferase immunoreactivity in the lumbar spinal cord of young adult and aged dogs

German Shepherds are a good model for research about aging and neurological disorders such as lumbosacral spinal canal stenosis. We compared neurons, glia and cholinergic neurons in the ventral horn of the lumbar spinal cord (L₃) between adult (1–2 years old) and aged (10–12 years old) groups. Any pathological findings were not found by hematoxylin and eosin staining and neurological examination, and the number of NeuN (a marker for neurons)-positive neurons were similar in both groups. Microtubule-associated protein 2 (MAP2) immunoreactive dendrites in the aged dog were decreased without any change in β-tubulin protein level. Glial fibrillary acidic protein (a marker for astrocytes) and ionized calcium-binding adapter molecule 1 (a marker for microglia) immunoreactivity were not significantly changed in both groups. The number of ChAT immunoreactive neurons was decreased; however, its protein level was not significantly changed in the aged group. These results suggest that numbers of ventral horn neurons are not changed, but cholinergic neurons may change in aged dogs compared to adult dogs.     

Analysis of the chemical coding of neurons in the intermediate thoracic ganglion of the pig

The pig has been widely used as a model in cardiovascular research. A unique feature of the porcine extrinsic sympathetic cardiac nerves is that they arise from intermediate ganglia in the thoracic cavity. The localization and pattern of distribution of nerve cell bodies and fibers containing tyrosine hydroxylase (TH), dopamine B-hydroxylase (DBH), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), galanin (GAL), methionine-enkephalin (MET) as well as calcitonin gene-related peptide (CGRP), substance P (SP) and pituitary adenylate cyclase-activating peptide (PACAP) was studied with immunohistochemistry. Almost all the neurons showed immunoreactivity to TH. Immunoreactivity to NPY, VIP, SOM, GAL, MET and PACAP was displayed by nerve cell bodies while nerve fibers exhibited immunoreactivity to all the neuropeptides studied. Therefore, it seems that the chemical coding of neurons and especially nerve fibers in the porcine intermediate ganglion share general similarities (with certain neurochemical variability), with porcine prevertebral ganglia (e.g., celiacomesenteric and caudal mesenteric ganglia).     

The distribution of calbindinD‐28k and parvalbumin immunoreactive neurons in the somatosensory area of the pigeon pallium

GABAergic interneurons regulate the degree of glutamatergic excitation and output of projection neurons. In this study, we investigated the distribution of calbindinD‐28k (CB) and parvalbumin (PV) in the somatosensory area of the pigeon pallium using immunohistochemical method. Our results show that anatomical structures of the somatosensory area of the pigeon pallium consisted of several subdivisions including the hyperpallium, intercalated hyperpallium, mesopallium, nidopallium and basorostralis. Neuronal density was significantly higher in the intercalated hyperpallium and basorostralis than that in the other subdivisions. The density of the CB immunoreactive neurons was generally similar in all the subdivisions; however, the density of PV immunoreactive neurons was particularly prominent in the basorostralis compared with that in the other subdivisions. In addition, the mean proportion of PV immunoreactive neurons to total neurons was higher than that in the CB immunoreactive neurons in all the subdivisions. In brief, our present study shows that PV immunoreactive neurons in the somatosensory area of the pigeon pallium were significantly abundant compared with CB immunoreactive neurons. This finding needs more studies regarding CB‐ and PV‐related functions in the somatosensory area of the avian pallium.     

Effect of total or partial uterus extirpation on uterus-projecting neurons in porcine inferior mesenteric ganglion. A. Changes in expression of transmitter-synthesizing enzymes--tyrosine hydroxylase,dopamine beta-hydroxylase and choline acetyltransferase

Expression of tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH) and choline acetyltransferase (ChAT) was studied with immunohistochemistry, in situ hybridization, RT-PCR and immunoblotting in two populations of neurons of porcine inferior mesenteric ganglion (IMG) projecting to the uterine horn and uterine cervix after axotomy induced by partial or total uterus extirpation in sexually immature gilts. Uterus-projecting neurons of the IMG were identified by retrograde tracing with Fast Blue. Additionally, the distribution of ChAT-positive (ChAT+) and Met-enkephalin-positive (ME+) nerve fibers around uterus-projecting neurons was studied with immunohistochemistry. Immunohistochemistry detected that extirpation-induced axotomy reduced dramatically TH, but not DBH, expression in the uterus-projecting neurons, while the expression level of ChAT remained unchanged. Hybridization in situ performed with molecular probes for TH and ChAT confirmed these findings. RT-PCR did not detect any changes in the expression of TH and ChAT at mRNA level between control and hysterectomized animals. Immunoblotting did not detect significant changes in the expression of TH and DBH in IMG after partial or total extirpation. However, it detected that after total extirpation of the uterus a new form of ChAT with apparent lower molecular mass appears in the IMG of hysterectomized animals. It was found also that the number of ChAT+ and ME+ nerve fibers is lower around axotomy-affected neurons than around neurons in control gilts. The results presented here show clear axotomy-associated changes in the expression of TH, but not DBH and ChAT in the uterus-projecting neurons of the porcine IMG, as well as changes in the expression of ChAT and ME in the preganglionic nerve fibers.     

Effects of L-dopa supplementation on concentrations of brain catechols, dopamine receptor binding and the incidence of pale, soft and exudative meat in stress-susceptible pigs

The purpose of this research was to determine if chronic dietary L-DOPA supplementation will alter differentially the brain catechol concentrations, dopamine receptor binding (KD and Bmax) and the incidence of pale, soft and exudative (PSE) meat in stress-susceptible (SS) and stress-resistant (SR) pigs. Stress-susceptible and SR pigs were assigned randomly to these four groups: SS pigs as controls, SR pigs as controls, SS pigs with L-DOPA supplementation and SR pigs with L-DOPA supplementation. The experiment began when pigs weighed 23 kg and terminated when pigs weighed 95 kg. Anatomical brain structures removed at slaughter included hypothalamus, thalamus, cortex, cerebellum, olfactory bulb, caudate nucleus, putamen and substantia nigra. Concentrations of norepinephrine and dopamine were greater in the hypothalami of SS than of SR control pigs. The L-DOPA supplementation eliminated the strain differences of brain catecholamine concentrations. Pigs fed L-DOPA had greater concentrations of dihydroxyphenylacetic acid in six of the eight brain regions analyzed than the controls. Dopamine receptor binding (Bmax and KD) of spiroperidol was similar in all four groups of pigs. Pale, soft and exudative pork developed to the same extent in SS pigs with or without L-DOPA treatment. The results suggest that L-DOPA supplementation eliminates strain differences in brain catecholamine concentrations but does not alter PSE meat development or striatal dopamine receptor binding.     

Immunohistochemical characterization of neurons in the porcine ciliary ganglion

The present study was aimed at disclosing the chemical coding of nerve structures in the porcine ciliary ganglion (CG) using immunohistochemical methods. The substances under investigation included markers of "classical" neurotransmitters, choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DbetaH) as well as neuropeptides, somatostatin (SOM), galanin (GAL), substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY). Immunoreactivity to ChAT and VAChT was found virtually in all the neuronal somata and in numerous intraganglionic, varicose nerve fibres which often formed basket-like formations around the nerve cell bodies. Many CG neurons contained immunoreactivity for SOM (46%) or GAL (29%). Interestingly, a small number (approx. 1%) of the cholinergic somata stained for TH but not for DbetaH; nevertheless, some extra- and intraganglionic nerve fibres displayed immunoreactivity for DbetaH or TH. The CG perikarya stained neither for vasoactive intestinal polypeptide (VIP) nor for neuropeptide Y (NPY), but some NPY- or VIP-positive nerve terminals were observed within nerve bundles distributed outside the ganglion. SP- and CGRP-immunoreactivity was found in some intraganglionic nerve fibres only. The present study revealed that the porcine CG consists of cholinergic neurons many of which contain SOM and GAL. Thus, it can be assumed that in the pig, these neuropeptides are involved, complementary to acetylocholine, in the parasympathetic postganglionic nerve pathway to structures of the eye including the ciliary and iris sphincter muscles.     

The enhanced expression of c-Jun immunoreactivity in the adrenalectomized gerbil hippocampus

Recent in vitro and in vivo studies have shown that glucocorticoids have a profound influence on the survival of hippocampal neurones, and that the depletion of glucocorticoids as a result of adrenalectomy (ADX) reduces nerve growth factor levels in the hippocampus. It is also believed that ADX is associated with the seizure susceptibility of the Mongolian gerbil. In the present study, the choronological changes of c-jun immunoreactivity were investigated after ADX in the hippocampal formations in the seizure-prone gerbil model. In the sham hippocampus, c-jun immunoreactivity was not observed in the neurones of the hippocampus proper and dentate gyrus. C-jun immunoreactive neurones appeared 3 h after ADX in the neurones of the CA1 area and dentate gyrus, and these immunoreactivities peaked 24 h after ADX and then gradually decreased. These results suggest that, in the adrenalectomized gerbil, c-jun may be expressed in the neurones of the hippocampus in compensation for glucocorticoid deficit. The result of enhanced c-jun expression of the hippocampal formation provides anatomical support for the hypothesis that c-jun may play a role in the reduction of seizure activity.     

Effects of bolus injection of epinephrine and norepinephrine on systolic time intervals in stress-resistant and stress-susceptible pigs

Systolic time intervals were measured in 15 stress-susceptible (SS) pigs to derive regression equations to determine to what extent their ventricular functions differed from those of stress-resistant (SR) pigs. Regression analysis revealed that the RR interval was the variable that was significantly (P less than 0.01) related to electromechanical systole and left ventricular ejection time. The preejection period (PEP) was independent of the RR interval. A normal increase of all systolic time intervals with age, independent of the RR interval, was also observed in SR and SS pigs. The 55-kg SS pigs had a higher noradrenergic tone than did 15-kg and 90-kg SS pigs, because their mean arterial blood pressure was higher and because their index values for electromechanical systole and their PEP were shorter than those of SR pigs of the same body weights. The cardiovascular responses to biogenic amines were also different according to the degree of development and stress susceptibility. Changes in mean arterial pressure and PEP were not as pronounced after injections of epinephrine and norepinephrine (10(-8) mol/kg of body weight) were given. Subsequently, a decrease in cardiovascular responses to epinephrine and norepinephrine injections in 90-kg SS pigs were recorded. These results indicate that 55-kg SS pigs have a higher level of circulating catecholamines and that the myocardium becomes less sensitive to epinephrine and norepinephrine after it is chronically exposed to these amines.     

Distribution and Activity of Fatty Acid Amide Hydralase (FAAH) in the Gastrointestinal Neurons of Mouse

The endocannabinoid anandamide may regulate intestinal motility through activation of CB1 receptors. Anandamide is then inactivated by fatty acid amide hydrolase (FAAH), a membrane bound enzyme. Under pathological conditions, inactivation of such enzymatic activity may lead to inhibition of the intestinal motility. Here, preliminary reports on the distribution of Fatty Acid Amide Hydrolase (FAAH) immunoreactivity in the mouse gastrointestinal neurons, and the pharmacological effects of N‐arachidonoylserotonin (AA‐5HT), a selective inhibitor of FAAH, are reported. FAAH was revealed by an indirect immunofluorescence. Laminar preparations containing the myenteric or the submucous plexus adhered, were peeled off after the whole gut wall had been stretched out and fixed in 4% paraformaldehyde. They were subsequently incubated with a polyclonal anti‐serum directed against a region near the N‐terminus of the human FAAH and revealed by a FITC‐conjugated goat anti‐rabbit secondary anti‐serum. FAAH‐immunoreactive neurons were observed within the myenteric ganglia throughout the GIT. The positive nerve cells varied in size and density of immunoreactivity. Stomach and large intestine showed the highest neuronal density. AA‐5HT significantly reduced both gastric emptying and gastrointestinal tract transit. Such inhibitory effect was reduced by the C1 receptor antagonist SR141716A. Both morphological and pharmacological results suggest that FAAH may play a critical role in controlling gut anandamide levels.     

Time-course changes of hippocalcin expression in the mouse hippocampus following pilocarpine-induced status epilepticus

Hippocalcin participates in the maintenance of neuronal calcium homeostasis. In the present study, we examined the time-course changes of neuronal degeneration and hippocalcin protein level in the mouse hippocampus following pilocarpine-induced status epilepticus (SE). Marked neuronal degeneration was observed in the hippocampus after SE in a time-dependent manner, although neuronal degeneration differed according to the hippocampal subregions. Almost no hippocalcin immunoreactivity was detected in the pyramidal neurons of the cornu ammonis 1 (CA1) region from 6 h after SE. However, many pyramidal neurons in the CA2 region showed hippocalcin immunoreactivity until 24 h after SE. In the CA3 region, only a few hippocalcin immunoreactive cells were observed at 12 h after SE, and almost no hippocalcin immunoreactivity was observed in the pyramidal neurons from 24 h after SE. Hippocalcin immunoreactivity in the polymorphic cells of the dentate gyrus was markedly decreased from 6 h after SE. In addition, hippocalcin protein level in the hippocampus began to decrease from 6 h after SE, and was significantly decreased at 24 h and 48 h after pilocarpine-induced SE. These results indicate that marked reduction of hippocalcin level may be closely related to neuronal degeneration in the hippocampus following pilocarpine-induced SE.     

Doublecortin-immunoreactive neuronal precursors in the dentate gyrus of spontaneously hypertensive rats at various age stages: comparison with Sprague-Dawley rats

Spontaneously hypertensive rats (SHRs) are widely accepted in medical research because this model has been used for studies in neurodegenerative diseases such as vascular dementia and stroke. In the present study, we observed newly generated neuronal precursors using doublecortin (DCX, a marker of neural proliferation and differentiation) in the subgranular zone of the dentate gyrus in SHRs compared to Sprague-Dawley rats (SDRs) at various age stages. DCX immunoreactivity, immunoreactive cell numbers and its protein level in the dentate gyrus of the SHRs were higher than those in the SDRs at postnatal month 1 (PM 1). At PM 8, DCX immunoreactivity, immunoreactive cell numbers and protein levels in both groups were markedly decreased compared to those at PM 1; however, they were higher than those in the SDRs. They were decreased in the both groups with age: DCX immunoreactive cells in the SDRs were few at PM 12. Our results indicate that newly generated neuronal precursors are more abundant in SHRs than in SDRs during their life.     

Immunohistochemical Localization of Galanin in Bovine Reproductive Organs

The vagina, uterus and oviduct were shown to receive galanin immunoreactive (GAL-IR) nerve fibres, the number of which varied between particular organs. In the ovary, GAL-IR nerves were absent. A small number of these nerves were located in the layers of the oviduct. A moderate number of GAL-IR nerves were situated in the body and uterine horns, whereas the uterine cervix and vagina wall contained a large number of GAL-IR nerve fibres, evenly distributed throughout particular membranes of the organs. GAL-IR nerves were found to contain, simultaneously, either vasoactive intestinal polypeptide (VIP), substance P (SP) or Leu⁵-enkephalin (ENK). Many of the GAL-IR nerves contained tyrosine hydroxylase (TH). A group of GAL-IR nerves that did not possess immunoreactivity to VIP, SP, ENK or TH was also observed.     

Ribosomal protein s3 immunoreactivity in the young, adult and aged gerbil hippocampus

Ribosomal protein S3 (rpS3) is well known to participate in DNA repair mechanisms. In the present study, we compared rpS3 immunoreactivity and its protein levels in the hippocampus among young, adult and aged gerbils. In the postnatal month (PM) 3 group as the young, rpS3 immunoreaction was observed in pyramidal and non-pyramidal cells of the hippocampus proper and in granule and polymorphic cells of the dentate gyrus. In the PM 12 group as adult and 24 group as the aged, rpS immunoreactivity in the hippocampus was decreased compared to the PM 3 group. Western blot analysis showed that rpS3 levels were decreased with time; lowest at PM 24. These results indicate that rpS3 immunoreactivity and protein levels were markedly decreased in the aged gerbil hippocampus.     

Laterality of spinocerebellar neurons in the chicken spinal cord

The aim in this study is to elucidate the laterality of chicken spinocerebellar (SC) neurons that originate from the caudal cervical to caudal lumbosacral spinal cord. SC neurons in the spinal segment (SS) 17-20 consisted of a mixture of crossed and uncrossed axons. SC neurons in the more cranial and caudal SS than SS 17-20 (transitional zone) were generally uncrossed and crossed, respectively. In the transitional zone, SC neurons in spinal border cells and ventral border cells of the ventral horn changed dramatically from an uncrossed to a crossed type between SS 17 and SS 18. Chicken SC neurons are markedly different in laterality from mammalian SC neurons.     

Parvalbumin‐immunoreactive cells in the olfactory bulb of the pigeon: Comparison with the rat

The olfactory bulb (OB) shows special characteristics in its phylogenetic cortical structure and synaptic pattern. In the OB, gamma‐aminobutyric acid (GABA), as an inhibitory neurotransmitter, is secreted from GABAergic neurons which contain parvalbumin (a calcium‐binding protein). Many studies on the distribution of parvalbumin‐immunoreactive neurons in the rodent OB have been published but poorly reported in the avian OB. Therefore, in this study, we compared the structure of the OB and distribution of parvalbumin‐immunoreactive neurons in the OB between the rat and pigeon using cresyl violet staining and immunohistochemistry for parvalbumin, respectively. Fundamentally, the pigeon OB showed layers like those of the rat OB; however, some layers were not clear like in the rat OB. Parvalbumin‐immunoreactive neurons in the pigeon OB were predominantly distributed in the external plexiform layer like that in the rat OB; however, the neurons did not have long processes like those in the rat. Furthermore, parvalbumin‐immunoreactive fibres were abundant in some layers; this finding was not shown in the rat OB. In brief, parvalbumin‐immunoreactive neurons were found like those in the rat OB; however, parvalbumin‐immunoreactive fibres were significantly abundant in the pigeon OB compared to those in the rat OB.     

鸡脑催乳素免疫反应神经元的分布

运用ＡＢＣ法观察了催乳素（ＰＲＬ）免疫反应神经元在鸡脑的分布。结果,ＰＲＬ阳性胞体主要分布在视交叉上核、视前室旁核、视上核、下丘脑室旁核、弓状核和伏隔核,旧纹状体、正中隆起存在大量阳性纤维末梢,在侧脑室腹侧的室管膜和脑基底神经胶质板上也存在ＰＲＬ阳性神经元。视前室旁核、视交叉上核、下丘脑室旁核、弓状核等核团内的ＰＲＬ阳性神经元有突起向第三脑室投射,伏隔核内及侧脑室室管膜上的ＰＲＬ阳性神经元有突起伸至侧脑室,视上核的ＰＲＬ阳性神经元也有突起投射至脑基底神经胶质板,表明鸡脑内的ＰＲＬ可以释放入脑室系统,参与调节脑－脑脊液神经体液回路。