AIM: To investigate the changes of somatosensory evoked potential(SEP), nitric oxide (NO) levels both in serum and in brain tissue after subarachnoid hemorrhage(SAH) and the influence of Ginkgo biloba extract(GBE) on them. METHODS: Wistar rats were divided into sham-operated group, pure SAH group and GBE-treated group. Dynamic changes of regional cerebral blood flow( rCBF),SEP, and NO levels both in serum and in brain tissue were detected within 24 hours after operation. RESULTS: In pure SAH group, rCBF decreased immediately after operation, with no tendency to recover within 24 hours. Latency of SEP delayed progressively from 1 hour to 24 hours after SAH.NO levels in serum and in brain tissue decreased and increased respectively from 1 hour to 24 hours after SAH. GBE effectively antagonized the changes of above parameters. CONCLUSION: SEP is useful in the judgement of cerebral ischemic damage after SAH. Decrease of serum NO and increase of brain NO are important factors leading to cerebral vasospasm and neural damage respectively after SAH. GBE relieves cerebral ischemic damage by reversing the pathological alterations of NO.

AIM: To investigate the effect of Ginkgo biloba extrac (GBE) on cerebral ischemia during early stage of subarachnoid hemorrhage (SAH). METHODS: Noncraniotomy models of SAH in Wistar rats were used and animals were divided into sham-operated group, SAH group and SAH+GBE group. Dynamic change of regional cerebral blood flow (rCBF) was detected. Brain endothelin-1(ET-1) and calcium contents were also determined at different time point during 24 hours after the operation. Pathological change of neurons of hippocampus CA1 region was observed. RESULTS: In SAH group, rCBF decreased immediately and persistently after induction of SAH. Values of brain ET-1 content and calcium content at 1 hour, 6 hours and 24 hours were significantly higher than those in sham-operated group. Neurons of hippocampus CA1 region were damaged severely 3 days after onset of SAH. Above abnormal changes in SAH+GBE group were much slighter than those in SAH group. CONCLUSION: GBE may relieve cerebral ischemic damage after SAH.

AIM: To investigate the changes of somatosensory evoked potential(SEP), nitric oxide (NO) levels both in serum and in brain tissue after subarachnoid hemorrhage(SAH) and the influence of Ginkgo biloba extract(GBE) on them. METHODS: Wistar rats were divided into sham-operated group, pure SAH group and GBE-treated group. Dynamic changes of regional cerebral blood flow( rCBF),SEP, and NO levels both in serum and in brain tissue were detected within 24 hours after operation. RESULTS: In pure SAH group, rCBF decreased immediately after operation, with no tendency to recover within 24 hours. Latency of SEP delayed progressively from 1 hour to 24 hours after SAH.NO levels in serum and in brain tissue decreased and increased respectively from 1 hour to 24 hours after SAH. GBE effectively antagonized the changes of above parameters. CONCLUSION: SEP is useful in the judgement of cerebral ischemic damage after SAH. Decrease of serum NO and increase of brain NO are important factors leading to cerebral vasospasm and neural damage respectively after SAH. GBE relieves cerebral ischemic damage by reversing the pathological alterations of NO.

AIM: To investigate the changes of bcl-2, bax expression and neuron apoptosis of cerebral cortex in lymphostatic encephalopathy of rats. METHODS: The model of lymphostatic encephalopathy was established by occluding and removing both the shallow and deep cervical lymph nodes in rats. The animals were sacrificed at 1, 2, 3, 5, 7 and 14 days after operation. HE staining was used to observe the structure of brain tissues and TUNEL staining was used to detect in situ cell apoptosis. The expressions of bcl-2 and bax were examined by RT-PCR. RESULTS: Cerebroedema appeared at the second day and was the most serious at the 5th day after blockage of cervical lymphatics. The number of TUNEL positive cells and the expression of bax began to increase at the 2nd day, reached a peak at the 5th day and dropped to control level at the 14th day. The expression of bcl-2 began to increase at the 1st day, reached a peak at the 5th day and dropped to control level at the 7th day. The increasing extent of bax was higher than that of bcl-2. CONCLUSION: The blockage of cervical lymphatics can lead to lymp[JP2]hostatic encephalopathy. Apoptosis is the main form of neuron death in the cortex and has relation to the increasing expression of bcl-2 and bax. [JP]

AIM: To investigate the role of nitric oxide in the development of brain edema after subarachnoid hemorrhage(SAH), and the influence of L-arginine on them. METHODS: Noncraniotomy models of SAH in Wistar rats were used and animals were divided into sham-operated group, SAH group and SAH plus L-arginine group. Dynamic changes of regional cerebral blood flow within 24 hours were measured. Serum nitric oxide level, brain water and sodium content at different time points within 24 hours were also detected. RESULTS: Regional cerebral blood flow and serum nitric oxide level at every time point after operation in SAH group were lower than those in sham-operated group, while brain water content and sodium content in the former group were higher than those in the latter group. Above pathological alterations in SAH plus L-arginine group were not so obvious as in SAH group. CONCLUSION: Decrease in serum nitric oxide plays a role in the development of brain edema after SAH, which may be partly reversed by administration of L-arginine.

AIM: To investigate the role of nitric oxide in neuronal damage induced by cerebral vasospasm (CVS) following subarachnoid he morrhage (SAH) in rats. METHODS: Noncraniotomy models of SAH by a endovascular puncture method in Wistar rats were used and animals were divided i nto sham-operated group, SAH group and SAH+L-arginine group. Dynamic changes of regional cerebral blood flow (rCBF) within 24 hours were monitored. Diameters of basilar artery (BA) were measured. Serum NO(NO - 2/NO - 3) and plasma endo thelin-1 content at different time points within 24 hours were also detected. RESULTS: Sham operation did not affect all of above parameters. In SAH group, rCBF reduced immediately after induction of SAH, reaching its lowe st at 1 h, persisting within 24 h. Diameter of BA significantly decreased after S AH. Serum NO - 2/NO - 3 decreased and plasma endothlin-1 increased statisti cally after SAH. In SAH+L-arginine group, decline of rCBF was not as rapid and s evere as that in SAH group. L-arginine also effectively antagonized vasospasm of BA and damage of hippocampal neurons. Decrease of serum NO - 2/NO - 3 and increase of plasma endothlin-1 were not so obvious in SAH+L-arginine group comp ared to SAH group. CONCLUSION: Decrease in NO is involved in the development of CVS- induced neuronal damage following SAH, and L-arginine partly increases serum NO and thus protectes ischemic brain neurons.

AIM To determine the effect of L-arginin e on cerebral blood perfusion following subarachnoid hemorrhage(SAH) in rats. METHODS Endovascular perforating SAH models were replicated in Wista r rats, and animals were divided into sham-operated group, SAH group and SAH+ L-arginine group. Dynamic changes of regional cerebral blood flow (rCBF) with in 24 hours were measured and serum nitric oxide(NO, NO - 2/NO - 3)levels at different time points within 24 hours were detected. Mean arterial blood pre ssure and blood gas were monitored during the experiment. RESULTS No obvious change in physiological parameters in the three groups was observed . rCBF and serum nitric oxide level at every time point after operation in SAH g roup were lower than those in sham-operated group. Pathological alterations abo ve in SAH+L-arginine group were less obvious than those in SAH group. CONCLUSION L-arginine, by antagonizing the decrease of nitric oxi de, exerts protective effect on secondary cerebral ischemia following SAH.

Objective To explore the influence of gender and age on auditory startle reflex in healthy adults.Methods A total of 150 healthy volunteers (92 males and 58 females) aged from 18 to 60 years were recruited for this study.A modified startle reflex paradigm was adopted.Furthermore,gender-age differences on startle magnitude,habituation,perceived spatial co-location induced prepulse inhibition (PSC-PPI) and perceived spatial separation-induced prepulse inhibition (PSS-PPI) in healthy volunteers were analyzed.Results ① There was no significant difference in amplitude and habituation of startie reflex between males and females (F=0.29,P=0.593;F=1.57,P=0.212).PSC-PPI and PSS-PPI were significantly higher in males (PSC-PPI:(34.68± 20.81) ％,PSS-PPI:(44.56 ± 23.19) ％) than those in females (PSC-PPI:(23.11±22.43)％,PSS-PPI:(35.21±25.09)％) (F=9.48,P=0.002;F=4.76,P=0.031).② There was a negative correlation between startle magnitude and age (r=-0.29,P＜0.01),however,no obvious correlations between age and PSC-PPI or PSS-PPI as well as habituation were observed.③Bivariate analysis of variance showed that no interaction between gender and age was found to the indexes of startle reflex(F=0.71-1.36,all P＞0.05).Conclusions There are differences for gender and age in the indexes of startle reflex.In detail,age chiefly influences startle magnitude,while gender mainly affects the prepulse inhibition.