Angiotensin II-mediated inhibition of noradrenergic neuroeffector transmission in the rat caudal artery may involve ati receptors

Abstract

In rat caudal artery preparations, the prejunctional enhancement of noradrenergic transmission by angiotensin n (Ang II) is increased by the AT, receptor antagonist Iqsartan, indicating an inhibitory action of Ang II which opposes its facilitation of norepinephrine (NE) release (Cox et al, 1995). We have investigated the receptors involved in the inhibitory effect and possible mediators Caudal arteries were labelled with [H]-NE and perfused and superfused with physiological salt solution. rH]-NE release was evoked by two periods of field stimulation (5 Hz, 30 s), 30 min apart Stimulation-induced (S-I) efflux of [TTJ-NE and S-I vasoconstriction with the second period of stimulation were incre..