It has been known that the Alzheimer's disease(AD)is related closely with a synaptic failure,and the p21-activated kinase(PAK)is well documented to play an important role in the regulation of the synaptie functions.However,the relationship between thePAK and the pathology of AD is unclear.In the present study,we examined the expressions of the PAK3(one subtype ofPAK),phospho-rylated-PAK(pPAK) and β-amyloid42(Aβ42,β-amyloid with 42 peptides)in an APP/PS1 double transgenie mouse model of AD andthe morphologies of geurOtlS in the hippocampus at different ages.The Western Blot results showed that the expression of PAK remainedunchanged,while,the expression of pPAK decreased largely at the age of 32 weeks and further decreased significantly with aging in thehippocampus of the APP/PS1 transgenic mouse.A1342 levels in the hippocampus were detected to increase as early as the age of 22 weeks,and kept the increase to continue with aging.The morphological results showed no obvious neuron loss in the sections of Nissl staining,while serious distonion and disorder of the dendrites of the hippocampal neurons were observed on the sections of Gelgi staining in theAPP/PS1 transgenic mouse.The present results suggested that it seemed something wrong in the processes of phospholization of PAK,butnot in the expression of the PAK itself;the toxic Aβ42 might affect the PAK in its phospholization,which in turn directly influence thedendritic development in the hippocampal neurons and cause the dendrites distorting and disordering.

To investigate whether HIV3B and HIV Ada-M can infect cultured human dorsal root ganglion (DRG) neurons, organotypic and dissociated human fetal DRG cell culture models were established. On the 14th day, organotypic cultured DRG explants were exposed to HIV3B or HIV Ada-M for another 14 days. Outgrowth and morphology of neurites were observed with phase contrast microscope at different time of cultured age. On the 3rd day, dissociated cultured DRG cells were exposed to HIV3B or HIV Ada-M for another 3 days. After that, dissociated DRG cells were processed for microtubule-associated protein 2 (MAP2) labeling and observed with fluorescent microscopy. DRG explants on the 28th day and dissociated DRG cells on the 6th day, the samples were processed for electronic microscopic observation. Both organotypic and dissociated DRG cultures were cultured continuously in culture media as controls. Immature HIV-like particles were found in organotypic cultured DRG neurons. Many HIV-like particles were found in dissociated cultured DRG neurons. HIV infection could not cause morphological and ultrastruc( )l alterations on both organotypic and dissociated cultured DRG neurons. These discoveries will be valuable for studies on pathogenic (mee)hanisms of HIV infection and/or HIV associated peripheral neuropathies.

With the aim to examine the distribution of high-affinity neurotrophin receptors (tyrosine kinase receptors, TrkA, TrkB and TrkC)in the rat Scapa's ganglion ( vestibular ganglion, VG), Avidin-Biotin-peroxidase Complex ( ABC ) method of immunohistochemistry with diaminobenzidine (DAB) as the chromogen to identify the immunoreactivities was employed in the present study. The results showed that many VG neurons were immunoreactive to each Trk isoform. The receptors were localized in the neuronal somata. The intensity of immunoreactivity for each Trk receptor was different among neurons, ranging from weak, moderate to intense. For each individual Trk receptors, the labelled neurons were of different size; the result sfatistical of analysis showed that the mean areas for neurons immunoreative to TrkA, B and C were 330.8 ± 7.6, 303.89 ± 10.6 and 355.05 ± 8.3 μm2 , respectively. The present study provids morphological substrate for the important roles played by Trk receptors in maintaining the survival and stabilizing the phenotype of VG neurons.

The structure and 5-HT immunoreactivity in the brain and suboesophageal ganglion of three beetles, Ambrostoma quadriimpressum, Henosepilachna vigintioctomaculata and Oxycetonia jucunda, were first studied by means of colophony-paraffin embedding serial section technique and strepteavidin-peroxidase immunohistochemical method. The results showed that the brains of these three taxonomically closely related beetles were remarkably different in composition and size. Mushroom bodies and antennal lobes in Oxycetonia jucunda were conspicuous. Calyces and lobes of the mushroom bodies.were much developed. In contrast, calyces of Ambrostoma quadriimpressum and Henosepilachna vigintioctomaculata were extremely undeveloped. However, the postretinal fibres and circumpharyngeal nerves of Ambrostoma quadriimpressum were highly developed. In the three beetles, 5-HT immunoreactivity was present in all neuropils of the brain and the suboesophageal ganglion. The pattern of 5-HT immunoreactivity and the localization of immunoreactive somata which often clustered into groups were similar among these beetles, while the immunoreactivity intensity was distinct, especially in the lamina. The results suggest that the three beetles have given rise to adaptive radiation under the evolutionary pressure because of the long-term different life styles and living environments in which the taxonomic status of Ambrostoma quadriimpressum is relatively low. The similarity of the pattern of 5-HT immunoreactivity and localization of some positive somata among the three beetles raise the possibility that 5-HT seemes to serve similar physiological function in different insects. Furthermore, 5-HT might be involved in modulating the ingestion by regulating muscular activity and visual sensitivity.

The present study investigated different types of eoexpression of brain derived neumtmphic factor(BDNF),nerve growth factor(NGF)and neutmphin-3(NT-3)mRNA and/or proteins in the left sixth lumbar dorsal root ganglion(DRG)of cats and discuss themechanism of coexpression in order to provide foundation for elucidating the relationship between the expression of neurotrophic factors andspinal cord plasticity.The eats used in this study were normal animals without any interventional treatment.They were subjected to renloveof the left L6 DRG and their DRG were processed for immunohistechemistry and in situ hybridization double staining to observe whetherthere are coexpression of mRNA and proteins of BDNF,NGF and NT-3.The results showed that the pmteios and mRNA of BDNF,NGFand NT-3 were all expressed in the DRG of cats,but the types of coexpression of mRNA and proteins were different and diverse amongthese three neumtrophic factors.The results of immunohiatochemistry showed that BDNF immunoreactivities were mainly observed in thecytoplasm and nucleus,and the staining of nucleus was weaker than that of cytoplasm;NGF immunoreactivities were mainly observed innucleus while NT-3 mainly in cytoplasm.The results of in situ hybridization showed that BDNF and NGF positive signals mostly distributedin the cytoplasm,NT-3 positive signals were observed in both the cytoplasm and nucleus.Our results suggest that the proteins and mRNAof BDNF,NGF and NT-3 have different types of coexpression which indicate they may have autocrine and/or paracrine mechanism contrib-uting to the plasticity of spinal cord in the left L6 DRG of cats.

To explore the relationship of mieroglia activation,motoneuronal loss in the ventral horn of spinal cord and sciatic nerve regen-eration after the sciatic nerve injury,Sprague-Dawley rats were prepared a modal of the fight sciatic nerve crash injury.The immunoreactiv-ity(-ir)ofmicroglia and number of the motoneurons inthe ventral horn of spinal cord were detected at 3 and7 days,light and electron mi-croscopic detection of sciatic nerve degeneration and regeneration were performed at 4 weeks after the nerve injury.The results showed:(1)At 3 days after the sciatic nerve injury,OX-42-irinthe ventral horn of spinal cord begantoincrease significantly(P<0.05);(2)The number ratio of motoneurons in ventral horn of spinal cord in ipsilateral to contralateral for injury decreased markedly(P<0.05),in-dicating the numbers of ipsilateral motoneuroanl survival decreased;(3)Histological assessment showed the poor regeneration of the in-jured nerves;(4)Simvastatin(an inhibitor of cholesterol biosynthesis,having potential immunomodulatory capacities)facilitated the mi-eroglial activation.the motoneuronal survival and sciatic nerve regeneration were better than non-simvastatin-treated vehicle rats.The pres-ent results suggest that mieroglia activation in the ventral horns ofthe spinal cord may play an important protective role in the nerve regener-ation after peripheral nerve injury of the rat.

To investigate the effects of didannsine(ddI)on the morphological alterations of dorsal root ganglion(DRG)neurons,dissoci-ated DRG cells from rat embryo were studied.DRG cells were cultured for 3 days and then treated with ddI for additional 3 claysin differ-ent concentrations(1μg/ml,5 μg/ml,10μg/ml and 20 μg/ml,respectively).Afarthat,DRG cells were processedformicrotubule as-soeiated protein 2(MAP2)labeling and observed under confocal laser scanning microscopy(CLSM).The results showed that both thenumber and length of neurites of the DRG cells after exposed to ddl significantly down-regulated in a dose-dependentmanner compared withcontrol group,thus suggesting that ddI may have inhibitory effects on neufite regeneration and outgrowth in dissociated DRG cultures.

To identify the role of spinal cyclooxygenase (COX)-1 in the development and maintenance of postoperative pain, we examined the changes of COX-1 protein expression in lumbar spinal cord by immunohistochemistry and Western blot technique in rat plantar incision model at different time points (pre-incision or 2 h, 4 h, 6 h,12 h, 1 d, 2 d, 3 d, 5 d and 7 d after incision). We also studied the anti-allodynic effects of the COX inhibitors by intrathecal administration of non-selective COX inhibitors (ketorolac), selective COX-1 (SC-560) or COX-2 inhibitor (NS-398) immediately or 2 h, 24 h after incision. The mechanical allodynia was evaluated by using paw withdrawal threshold (PWT) response to mechanical stimulation on pre-incision, 2 h, 1 d, 2 d, 3 d, 5 d and 7 d after incision or 30 min after drug treatment. The result showed that COX-1 immunoreactive cells mainly focused in the superficial laminae of lumbar spinal dorsal horn and expression of spinal COX-1 protein increased after incision, peaked at 4 h (P＜0.01) and lasted for 12 h. Postoperative treatment with both SC-560 and ketorolac significantly alleviating the mechanical allodynia induced by skin incision, but NS-398 had no such effect. This study demonstrates that spinal COX-1 involves in the development and maintenance of postoperative hypersensitivity and intrathecal COX-1 inhibitor has anti-allodynic effect on incision pain in the rat.

Whole-cell patch clamp technique was performed on acutely isolated rat dorsal root ganglion (DRG) neurons to investigate the modulatory effect of caffeine on γ-aminobutyric acid (GABA)-activated currents (IGABA). The results showed that the majority of the neurons examined (97.4%, 113/116) were sensitive to GABA. 1-1000 μmol/L GABA activated a concentration-dependent inward current which manifested obvious desensitization. After the neurons were treated with caffeine (0.01-100 μmol/L) prior to the application of GABA (100 μmol/L) for 30 s, GABA-activated membrane currents were obviously inhibited. Caffeine shifted the GABA dose-response curve downward and decreased the maximum response to 57% without changing Kd value. These results indicate that the inhibitory effect is non-competitive. Theophylline showed a similar and stronger inhibitory effect on IGABA. The pretreatment with caffeine (10 μmol/L) inhibited IGABA, which was potentized by diazepam (1 μmol/L). Intracellular application of H-8 almost completely abolished the inhibitory effect of caffeine on IGABA. The present results suggest that caffeine may be able to antagonize the effect of presynaptic inhibition of GABA in primary afferent.

Effects of urotensin II (UII) on paraventricular nucleus (PVN) neurons of hypothalamus from brain slices of rats were examined by using extracellular recording technique. The results are as follows: (1) In response to application of UII (0.3, 3.0, 30.0, 300.0 nmol/L, n=39) into the perfusate for 2 min, the spontaneous discharge rates (SDR) of 32/39 (82.05% ) neurons were significantly decreased in a dose-dependent manner; (2) Pretreatment with bicuculline (BIC, 100 μmol/L), a specific GABAA receptor antagonist, led to a marked increase in SDR of 5/7 ( 71.43% ) neurons in an epileptiform pattern. The increased discharges were not significantly changed after UII ( 30.0 nmol/L ) was applied into the perfusate for 2 min; (3) Pretreatment with picrotoxin ( PIC, 50 μmol/L ), a selective blocker of Cl- channel, led to an increase in the SDR of all 12/12 (100%) neurons. The increased discharges were not influenced by the applied UII (30.0 nmol/L) for 2 min in 11/12 (91.67%) neurons; (4) Application of nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 50 μmol/L ) into the perfusate could significantly augment the SDR of 11/12 ( 91.67% ) neurons , while UII ( 30.0 nmol/L ) applied into the perfusate for 2 min led the augmented SDR of all (12/12, 100%) neurons decrease. The results suggest that UII decreases the excitability of PVN neurons of hypothalamus by potentiating GABAA receptor-mediated Cl- current.