Abstract
The aims of this study were to investigate the effect of adenosine triphosphate (ATP), which has been known as the neurotransmitter of nonadrenergic, noncholinergic nerves, and the source of $Ca^{\sharp}$ in the effect of ATP on the isolated renal artery of pig. The results of this study were summarized as follows: 1. ATP caused the contraction and the contractile responses were increased in a dose-dependent manner between the concentration of ATP $2{\times}10^{-3}M$ and $10^{-2}M$ on the isolated renal artery of pig. 2. The contractile responses induced by ATP $(5{\times}10^{-3}M)$ were not blocked by pretreatment with cholinergic receptor blocker (atropine, $10^{-6}M$), $\alpha$-adrenergic recptor blocker(phentolamine, $10^{-6}M$) or $\beta$-adrenergic receptor blocker (propranolol, $10^{-6}M$), and $H_1$-receptor blocker (pyrilamine, $10^{-6}M$) or $H_2$-receptor blocker (cimetidine, $10^{-6}M$) on the isolated renal artery of pig. 3. The contractile responses induced by ATP $(5{\times}10^{-3}M)$ were not appeared in $Ca^{\sharp}$-free medium. As the concentration of $Ca^{\sharp}$ in $Ca^{\sharp}$-free medium was increased, the contractile responses induced by ATP $(5{\times}10^{-3}M)$ were enhanced but were completely inhibited by pretreatment with $Ca^{\sharp}$-channel blocker, papaverine $(5{\times}10^{-5}M)$ or verapamil $(5{\times}10^{-5}M)$ on the isolated renal artery of pig.