Tyrosine kinases participate in alpha 1A-adrenoceptor-mediated vasoconstriction in perfused rat hindlimb.

AIM: To determine whether or not tyrosine kinase is involved in the signal transduction of alpha 1A-adrenoceptors. METHODS: Effects of various pharmacological probes on norepinephrine (NE)-induced vasopressor responses were determined in the perfused rat hindlimb. RESULTS: The putative tyrosine kinase inhibitors, genistein, and tyrphostin, significantly inhibited the vasopressor responses induced by NE but not that induced by KCl. The protein-tyrosine-phosphatase inhibitor, sodium orthovanadate, selectively potentiated the vasopressor responses induced by NE. Neither genistein nor tyrphostin had effect on the contraction elicited by phorbol 12-myristate 13-acetate. In contrast, both genistein and tyrphostin attenuated the vasopressor responses evoked by NaF. CONCLUSION: The genistein- and tyrphostin-sensitive tyrosine kinases participate in alpha 1A-adrenoceptor-mediated vasoconstriction in perfused rat hindlimb.