AIM To study the effects of different kinds of chloride channel blockers on KCl and 5 HT induced contractile responses in cerebrovascular smooth muscle. METHOD The tension of rabbit basilar artery rings was measured. RESULTS ① DIDS, furosemide and NPPB inhibited the responses to KCl and 5 HT in a concentration dependent manner. The effects of DIDS, furosemide and NPPB on the response to 5 HT were stronger than that to KCl. ②When SK&F 96365 evoked a maximum inhibitory effect on 5 HT induced response, subsequent additions of DIDS, furosemide and NPPB could further produced vascular relaxation. CONCLUSION The chloride channel participates KCl and 5 HT induced contractile responses in cerebral basilar artery.

AIM To study the effects of protein tyrosine kinase inhibitor and protein tyrosine phosphatase inhibitor on cultured bovine cerebrovascular smooth muscle cells (CSMC) Ca 2+ store operated Ca 2+ influx. METHODS Cell culture and single intracellular free Ca 2+ concentration was measured in fura 2/Am flueorescence probe by MetaFluor Fluorescence ratio imaging system. RESULTS (1) protein tyrosine kinase inhibitor (genistein,2.5,5,10 ?mol?L -1 )decreased Ca 2+ influx significantly induced by endothelin 1(ET 1),ATP,cyclopiazonic acid(CPA) in concentration dependent manner; (2) Protein tyrosine phosphatase inhibitor (vanadate,2,4,8 ?mol?L -1 ) increased Ca 2+ influx significantly induced by ET 1,ATP,CPA in concentration dependent manner. CONCLUSION Protein tyrosine kinase inhibitor and protein tyrosine phosphatase inhibitor have effects on Ca 2+ store operated Ca 2+ influx induced by ET 1, ATP, CPA. Protein tyrosine phosphorylation participats in the signal transduction of Ca 2+ store operat Ca 2+ influx in cerebrovascular smooth muscle cells.