[Experimental study of pituitary adenylate cyclase activating polypeptide on relieving brain edema induced by
1Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
Aim:
In order to study the effects of pituitary adenylate cyclase activating polypeptide(PACAP) on brain edema induced by ischemia in rats and its underlying receptor mechanism.
Methods:
Brain ischemia model in rats was established by ligaturing four--vessels. The percentage ratio of wet over dry tissue weight, sodium and potassium contents of dry brain tissue were measured by weighing and enzymatic analysis methods.
Results:
The brain water contents significantly increased after rats exposed to 1 h of reperfusion following 30 - minute ischemia. Furthermore, sodium contents in brain tissue increased and potassium contents decreased following perfusion. Changes of brain water contents, sodium and potassium contents were relieved by lateral ventricular injection of PACAP in the concentration of 1 x 10(-9), 1 x 10(-10) or 1 x 10(-11) mol respectively before ischemia. The effect of PACAP could be blocked by MCAP6 - 38 (specific type I PACAP receptor antagonist) lateral ventricular injection prior to PACAP administration.
Conclusion:
Exogenous PACAP may act as a protective effect in brain edema induced by ischemia in rats, which is mediated by type I receptor.
