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^(++) in the effect of ATY on ihe 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 2×10^(-3)M and 10^(-2)M on the isolated renal artery of pig.
2. The contractile responses induced by ATP (5×10^-3M) were not blocked by pretreatment with cliolinergic receptor blocker(atropine, 10^(-6)M), α-adrenergic recptor blocker(phentolamine, 10^(-6)M) or (β-adrenergic receptor blocker (propranolol, 10^(-6)M), and H₁-receptor blocker (pyrilamine, 10^(-6)M) or H₂-receptor blocker (cimetidine, 10^(-6)M) on the isolated renal artery of pig.
3. Thc contractile responses induced by ATP (5×10^(-3)M) were not appeared in Ca^(++)-free medium. As the concentration of Ca^(++) in Ca^(++)-frec modium was increased, the contractile responses induced by ATP (5×10^(-3)M) were eahanced but wrre completely inhibited by pretreatment with Ca^(++)-channel blocker, papaveriuc (5×10^(-5)M) or verapamil (5×10^(-5)M) on the isolated renal artery of pig.
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