EFFECTS OF EXTRACELLULARLY APPLIED ATP AND ITS RELATED NUCLEOTIDES ON THE MEMBRANE POTENTIAL OF THE GUINEA-PIG TAENIA COLI

概要

論文の詳細を見る
Experiments were performed to examine whether ATP or its related nucleotide is the possible transmitter substance of the non-adrenergic inhibitory nerves of the guinea-pig taenia coli by the intracellular microelectrode technique. In the presence of atropine (10-6 g/ml), field stimulation with square-wave pulses elicited hyper-polarization of the guinea-pig taenia coli which is so-called the "inhibitory potential." Extracellularly applied ATP, ADP, AMP and adenosine also hyperpolarized the membrane and blocked the spontaneous spike discharge. Among them, ATP and ADP were equally the most potent. Tetrodotoxin (10-7 g/ml) prevented the inhibitory potential elicited by field stimulation, though it had no influence on the inhibitory action of ATP. Imidazole (3.5×10-3g/ml) and phentolamine (10-5 g/ml) antagonized the inhibitory action of ATP and other adenosine nucleotides. However, these agents failed to abolish the inhibitory potential elicited by field stimulation. Quinidine (5×10-5-2×10-4g/ml) antagonized the inhibitory potential elicited by field stimulation and blocked the spontaneous spike discharge, but failed to abolish the inhibitory action of ATP. It may be improbable from these data that ATP or other adenosine nucleotide is the transmitter substance of the non-adrenergic inhibitory nerves.
日本平滑筋学会の論文