Abstract
To elucidate the action of $P_2$-purinoceptor, effects of adenosine triphosphate(ATP) and perivascular nerve stimulation were investigated from polygraph in the isolated renal artery of rabbit 1. ATP caused the relaxation on the precontraction with noradrenaline$(10{\mu}M)$ on the presene and absence of endothelium in the isolated renal artery of rabbit, the relaxative response was increased between 0.1 and $30{\mu}M$ on dose-dependent manner. 2. The relaxative response induced by ATP$(10{\mu}M)$ on precontraction with noradrenaline$(10{\mu}M)$ was blocked by the pretreatment with reactive blue 2$(10{\mu}M)$. 3. ATP inhibited the contractile response by perivascular nerve stimulation(0.3ms, 80V, 50Hz, 1 sec), the inhibitory action was blocked by the pretreatment with 8-phenyltheophylline$(10{\mu}M)$.