Effects of purinergic nerve on relaxation of pig coronary artery

돼지 심관상동맥의 이완작용에 대한 purinergic 신경의 효과

To elucidate the effects of purinergic nerve on relaxation of pig coronary artery, the effects of ATP, 2-methylthio ATP and electrical perivascular nerve stimulation were investigated from physiograph on the isolated coronary artery of pig. The results btained were as follows; 1. The relaxative responses induced by perivascular nerve stimulation(20V, 0.5msec, 10sec) were the frequency(1~8Hz) dependent manner with phentolamine($10^{-5}M$) and atropine($10^{-6}M$) on isolated coronary artery of pig. 2. The relaxative responses induced. by adenosine($10^{-7}{\sim}5{\times}10^{-3}M$) or ATP($10^{-7}{\sim}5{\times}10^{-5}M$) on precontraction with histamine($10^{-5}M$) were the dose-dependent manner, but the contractile responses were often induced by ATP($10^{-4}M$ and $10^{-3}M$). 3. The relaxative responses induced by 2-methylthio ATP($2.5{\times}10^{-8}{\sim}2.5{\times}10^{-6}M$) on precontraction with histamine($10^{-5}M$) were the dose-dependent manner. 4. The relaxative response induced by 2-methylthio ATP($10^{-7}M$) on precontraction with histamine($10^{-5}M$) was completely blocked by the pretreatment with $P_{2Y}$-purinoceptor blocker, reactive blue 2($10^{-4}M$). 5. The neurogenic relaxative response induced by perivascular nerve stimulation(20V, 8Hz, 0.5msec, 10sec) was weakly inhibited by the pretreatment with ${\beta}$-adrenoceptor blocker, propranolol($10^{-5}M$) and blocked by the addition with $P_{2Y}$-purinoceptor blocker, reactive blue 2($10^{-4}M$). The results suggest that the purinergic nerve is innervated, and its relaxative response was mediated by $P_{2Y}$-purinoceptor on isolated coronary artery in pig.