Inhibitory effects of trifluoperazine and chlorpromazine, calmodulin inhibitor, on autoregulation of renal blood flow.

An intra-arterial infusion of a calmodulin inhibitor trifluoperazine (3 mg/min) or chlorpromazine (5 mg/min) caused obvious inhibition of autoregulation of renal blood flow in dogs. Simultaneous infusion of CaCl2 (30 mg/min) or Ca channel activator BAY K 8644 (5 micrograms/min) with these calmodulin inhibitors reduced renal blood flow, but could not block the inhibitory activity of calmodulin inhibitors on the autoregulation. The present experiment shows the contribution of the Ca-calmodulin system to the mechanism of autoregulation of renal blood flow.