To investigate the expression change of BDNF in lamina II of spinal cord from partial deafferented cats, L6 segmentsof spinal cord from 20 adult male cats (5 normal cats, 15 unilateral L6 spared roots cats allowed to survive 3 d, 6 d and 12 d re-spectively) were stained with immunohistochemical technique. The results showed: BDNF positive products were mainly dis-tributed in nerve terminals, varicosities and few neurons of spinal cord lamina II in normal cat. After operation, the density ofpositive nerve terminals and varicosities began to decrease on the third day, reached the lowest level on the 6th day and recoveredto normal level on the 12th day on operated side. But the number of BDNF neurons showed no obvious change. The authors sug-gest that the decreased density of BDNF positive products in lamina II on the 3rd and 6th day was related with the degenerationof the nerve fibers and varicosities after section of the adjacent dorsal roots. On the 12th day, the remaining L6 dorsal roots un-derwent collateral sprouting compensatoryly and reestablished functional connection with target neurons. Therefore, BDNF maybe involved in the normal physiological function and the plasticity of spinal cord after damage.

To understand the relationship of neurotransmitter between the striatum and limbic system such as amygdaloid nucle-us and bed nucleus of the stria terminalis. 30 male Sprague Dawley rats were used. Immunohistochemical ABC method was per-formed to detect the expression of substance P (SP), calcitonin gene-related peptide (CGRP), leucine-enkephalin (L-enk),cholecyctokinin (CCK) and neuronal nitric oxide synthase (NOS) on seetions of the brain. Some transmitters including substanceP, calcitonin gene-related peptide and cholecyctokinin were mainly distributed at the marginal division of the striatum. Theleucine-enkephalin was mainly distributed at the globus pallidus and was secondly distributed at the marginal division of the stria-tun. The neuronal nitric oxide synthase was mainly distributed at caudate putamen and the marginal division. All these transmit-ters were not only distributed at amygdaloid nucleus and bed nucleus of the stria terminalis, but also had fibers connection amongthe amygdaloid nucleus, marginal division and bed nucleus of the stria terminalis. CONCLUSION: There were special fibersconnection between the marginal division and other basal ganglia nucleus or the limbic system. The marginal division may beplayed some important functions of basal ganglia and limbic system.

In order to investigate the chemical and morphornetrical properties of the neuronal precursor cells derived from thesubventricular zone(SVZ) of the postnatal rat forebrain in vitro. The cell-type specific antibodies were used for the immunocy-tochemical staining ,and the morphometric parameters which were the mean soma diameter and the ellipticity index (i. e. , thesmallest soma diameter divided by the largest soma diameter) of every SVZ-derived cell were measured for identifying the pheno-types of the SVZ cells in vitro. The experiment animals were SD rats (weights: 100～ 150 g), the SVZ cells derived from thepostnatal rats were cultured on poly-D-lysine-coated 24-well glass chamber slides in the Neurobasal Medium supplemented withB27 in 5% CO2 at 37 C. The following results were obtained.. At 1 day in vitro, almost all SVZ cells (〉90%) from the postna-tal rat forebrain expressed Tujl, an antibody that recognizes neuron-specific tubulin. Likewise, the preponderance of the SVZcells expressed the polysialylated neural cell adhesion molecule (PSA-N-CAM) ; The majority of the SVZ Tujl-positive cells cul-tured were the cells that had oval-shaped bodies with two short, unbranched processes protruded from every two poles, theirmean soma diameter were 8.42±1.03μm and their ellipticity index were 0.57±0.12. Meanwhile, there were approximately20% of the SVZ cells in culture that were sphere-shaped cells with mean soma diameter 7.20±l.04 μm , and it might be observed that these cells connected with one another. As the time in culture went on, these sphere-shaped SVZ-derived cells alsotransformed to oval-shaped ones as described above, but it could be observed that the cells were still connected in the processesof them. By 3 and 5 days in culture, the SVZ cells had larger cell somas (average diameter 9. 07±1.07 μm), and often consider-ably longer processes but still with few branches. Immunocytochemical staining revealed that the majority of the SVZ cells in cul-ture remained Tujl-positive, PSA-N-CAM-positive. By 7 days in culture, the Tujl-positive cells in culture showed remarkablemorphological changes, and possessed typical neuronal phenotypes, which had more larger cell somas (average diameter 12.8 ±1.13 μm), and had more longer, branched processes. Our results showed that the SVZ in the postnatal SD rats contained theneuronal precursor cells which were PSA-N-CAM-positive and could differentiate into new neurons in vitro.

After injecting retrograde tracer fiuoro-gold (FG) into the parabrachial region(PB), caudal ventrolateral medulla(CVLM) and the fourth segment of cervical spinal cord (C4), respectively, neurons in laminae I ～ Ⅱ of the medullary dorsalhorn projecting to the above mentioned brain areas were observed. PB received projections from bilateral laminae I and Ⅱ withan ipsilateral dominance; CVLM and C4 received projections from ipsilateral laminae I and Ⅱ. Neurons projecting to C4 werevery sparsely distributed in laminae I and Ⅱ of the medullary dorsal horn. The projecting neurons in outer part of lamina Ⅱwere more than those in inner part of lamina Ⅱ . Combined with immunofluorescence histochemistry for calbindin-D28k(CB) andparvalbumin(PV), it was demonstrated that a part of neurons projecting to PB or CVLM showed CB-like immunoreactivity, butnone of them exhibited PV-like immunoreactivity. There were only a few neurons in lamina Ⅱ projecting to C4 and they exhibitedneither CB- nor PV-like immunoreactivity. The present study provides further evidence for the existence of projecting neurons inlamina Ⅱ and suggests that immunostaining against CB and PV may distinguish two neuronal subpopulations in lamina Ⅱ .

To investigate effects of cultured astrocytes from Sprague Dawley rat cerebral cortex on the development of PC12 cellsderived from rat pheochromocytoma, PC12 cells were cocultured with astrocyte according to different astrocytes/neurons ratio(50:1～1:1) , or with serum-free conditioned medium of astrocytes(ACM). The vitality of PC12 cells was measured by sensi-tive MTT method and their morphologic features were observed by Olympus light microscope. The results showed: (1) WhenPC12 cells were cultured with ACM, compared with the control group, the vitality of PC12 cells was increased significantly (0.255+0. 012 vs 0. 510±0. 036, P<0. 001) and the morphological changes were not obvious in the experimental group. (2) WhenPC12 cells were cocultured with astrocyte in the ratio of 30: 1～1: 1, not only was the vitality of PC12 cells enhanced, but alsothe neurite-outgrowth of PC12 was observed. (3) When PC12 cells were cocuhured with astrocyte in proportion of 50: 10～40 : 1, the vitality of PC12 cells was also enhanced, but the neurite-outgrowth of PC12 was not found. This study suggested en-hancement of PC12 cell-vitality was mediated by soluble factors produced by astrocytes, while activity of the neurite-promotingwas associated with cell-cell contact and with the ratio of two cells.

The involvement of astrocytes and correlation between neuronal injury and astrocyte response were studied. Blockingmiddle cerebral artery and reperfusing o. 5～48 h, H-E staining, immunoccytochemistry single-and double-labeling, dotble label-ing combined with TUNEL and GFAP immunocytochemistry were used to investigate neuronal injury and astrocyte response.The is chemic area peaked at 24 h of reperfusion. The neurons presented irreversible degeneration at 6 h of reperfusion. At24 h,ischemic area in the preoptic area developed into infarcted area; astrocytes exhibited differential morphological features: reactive,malnourished and degenerative changes. At 48 h of reperfusion, the number of astrocytes began to go up. The astrocytes in is-chemic area didn't proliferate within 48 h. By contrast, a few astrocytes underwent apoptosis. In conclusion, these data indicatethat the reaction of astrocytes is closely connected with the extent of neuronal injuries. The reactive astrocytes imply that astro-cytes positively respond to the neuronal injuries, which might play a role in promoting neuronal survival.

The purpose of the present work is to observe cGMP positive cells after cerebral ischemia-reperfusion in the gerbil hip-pocampus. Immunofluorescent methods were used in gerbil hippocampal tissue slices. The results showed that after cerebral is-chemia cGMP synthesis in the CAi-a subfields was increased, cGMP positive cells were distributed mainly in CA1 subfield. Mostof cGMP positive cells were astrocytes. The number of small round cGMP positive cells were increased after recirculation follow-ing ischemia in the dentate gyrus. These results indicate that after cerebral ischemia cGMP synthesis was increased in the CA1-asubfield, It is possible that astrocytes play an important role in the regulation of metabolism in the early stage after ischemia-reperfusion.

The distribution of TrkA and the postnatal development(PD) of TrkA and ChAT-immunoreactive(-IR) neurons andthe relation between them in the basal nucleus of Meynert of rats were studied with immunohistochemical method. The number,mean profile areas and grey degree of TrkA-IR and ChAT-IR neurons were examined with image analyser. The data revealed thatTrkA-IR neurons were localized in the basal forebrain of rats. TrkA immunostaining was present at PDI, but ChAT was not.ChAT immunostaining was present at PD5. Most densely stained TrkA and ChAT neuronal bodies and fibers were present atPD20, the mean grey degrees of TrkA-IR and ChAT-IR neuronal profiles reached its peak. Both TrkA and ChAT neurons beganto cline at PD30 and maintained a relatively higher level in the adult. However, during aging both TrkA and ChAT-IR neuronsatrophy and became smaller than that in the adult. The number of TrkA-IR and ChAT-IR neurons were decreased by 41.38% and 51.61%; the mean profile areas decreased by 15.7% and 12.8%; and the mean grey degrees by 29.9% and 9.9%, respec-tively. The mean profile areas of TrkA-IR and ChAT-IR neurons from PD5 to aged rats were positively correlated. The resultsindicated that the expression of TrkA was earlier than ChAT. The expression of TrkA and ChAT followed a very similar tempo-ral pattern in the basal nucleus of Meynert from PD5 to aged rats, suggesting that TrkA might participate the regulation ofChAT-IR neuronal development, differentiation, maturation, and ageing. The down-regulation of TrkA and ChAT of aged ratsis associated with neuronal atrophy and loss and may contribute to the pronounced vulnerability of these neurons to degenerationin aging animals and Alzheimer's disease.

The special trichrome stain and immunocytochemical stain were used to show neurites, Schwann's cells in cultured pe-ripheral nerve tissue. The dorsal root ganglia(DRG) of rat were cultured on polypyrrole membrane for 2 weeks. Then, the cul-tured speciments were stained by special stain, which was composed of hematoxylin, fast green FCF. ehromotrope 2R and phos-photungstic acid; or by immunocytochemical stain with anti-S-100 protein and anti-neurofilament antibodies. In the specialtrichrome stained specimen the long processes from DRG were stained aquamarine blue; part of the cell nuclei on the processes orpolypyrrole membrane were stained red or purplish red, and the cytoplasm ashen. We testified that the long processes from DRGwere neurites and the cells which were purplish red nuclei and ashen cytoplasm were Schwann's cells in immunocytochemicalstain. The special staining could differentiate neurites and Schwann's cells in cultured peripheral nerve tissue.

By using extracellular single unit recording technique, locally suppressive effects of a single dose of ketamine on sub-cutaneous (s. c. ) bee venom-induced increase in firing of wide dynamic-range (WDR) neurons in spinal dorsal horn were investi-gated on urcthane-chloralose anesthetized cats. Injection of bee venom s.c. into the cutaneous receptive field (RF) resulted in asingle phase of prolonged, persistently increased firing of WDR neurons over background activity for more than 1 h. Local pre-treatment with ketamine (100 mM, 0. 1 m l) into the center of RF where bee venom was injected produced a dramatic suppressionof the increased neuronal firing by 60% (3.10± 0.42 spikes/s, n= 5) when compared with saline pre-treated group (7.61 ± 0.17spikes/ s. n = 5 ). Moreover, local post-treatment with the same dose of ketamine also produced a profound suppression of the in-creased neuronal activity by 81% (1.51±0.06 spikes/s, n=5) when compared with the saline post-treated group (7.76±0.15spikes s, n=5). However, s.c. administration with the same dose of ketamine into a symmetrical region on the bee venom un-treated contralateral hindpaw produced no affection on the increased firing of the WDR neurons, suggesting that the suppressiveaction of local ketamine was not the result of systemic effects. The present result suggests that ketamine may exert its localantinociceptive effects mainly through the peripheral NMDA receptors in addition to its partially potential blocking effects onsodium and voltage-sensitive calcium channels.