Background. Our previous studies indicated that the increased arginine vasopressin（AVP） in ischemic brain regions of gerbils could exacerbate the ischemic brain edema. This experiments is further clarify the relation between AVP and cerebral ischemia at the molecular level. Methods. The contents of AVP

AVP mRNA

AVP immunoreactive（ir） neurons in supraoptic nucleus（SON） and paraventricular nucleus（PVN） after cerebral ischemia and reperfusion were respectively determined by radioimmunoassay（RIA）

immunocytochemistry（ⅡC）

situ hybridization and computed image pattern analysis. Results. The contents of AVP in SON

PVN were increased

and the AVP ir positive neurons in SON and PVN were also significantly increased as compared with the controls after ischemia and reperfusion. And there were very light staining of AVP ir positive neurons in the other brain areas such as suprachiasmatic nucleus （SC） and periventricular hypothalamic nucleus （PE）

but these have no significant changes as compared with the controls. During different periods of cerebral ischemia （30～120 min） and reperfusion （30 min）

AVP mRNA expression in SON and PVN were more markedly increased than the controls. Conclusions. The transcription of AVP gene elevated

then promoting synthesis and release of AVP in SON

PVN. Under the specific condition of cerebral ischemia and reperfusion

the activity and contents of central AVP increased abnormally is one of the important factors which causes ischemia brain damage.