Ribeiro J A, Sebastião A M
Br J Pharmacol. 1984 Oct;83(2):485-92. doi: 10.1111/j.1476-5381.1984.tb16511.x.
The effects of adenosine, adenosine analogues (N6-cyclohexyladenosine (CHA), L-N6-phenylisopropyladenosine (L-PIA), D-N6-phenylisopropyladenosine (D-PIA), N6-methyladenosine and 2-chloroadenosine), adenine, inosine, hypoxanthine, cyclic AMP and its analogue the dibutyryl cyclic AMP (db cyclic AMP), and methylxanthines (theophylline, caffeine and isobutylmethylxanthine (Ibmx) on compound action potentials were investigated in de-sheathed sciatic nerve preparations of the frog. Adenosine and its analogues enhanced, in a concentration-dependent manner, the inhibitory action of tetrodotoxin (TTX) on nerve conduction. The order of potencies was: CHA greater than D-PIA greater than L-PIA greater than N6-methyladenosine greater than 2-chloroadenosine greater than adenosine. The adenosine metabolites, inosine and hypoxanthine, were inactive on TTX-induced axonal blockade. Adenine enhanced the inhibitory action of TTX on nerve conduction, but was less effective than adenosine. db Cyclic AMP, but not cyclic AMP, mimicked the inhibitory effect of adenosine on nerve conduction. Methylxanthines did not antagonize the effect of adenosine on TTX-induced axonal block and in high concentrations also mimicked the effect of adenosine on nerve conduction. The possibility of adenosine acting on TTX-induced axonal block through an adenosine receptor positively coupled to adenylate cyclase is discussed.
在青蛙的去鞘坐骨神经标本中，研究了腺苷、腺苷类似物（N6-环己基腺苷（CHA）、L-N6-苯异丙基腺苷（L-PIA）、D-N6-苯异丙基腺苷（D-PIA）、N6-甲基腺苷和2-氯腺苷）、腺嘌呤、肌苷、次黄嘌呤、环磷酸腺苷及其类似物二丁酰环磷酸腺苷（db环磷酸腺苷）以及甲基黄嘌呤（茶碱、咖啡因和异丁基甲基黄嘌呤（Ibmx））对复合动作电位的影响。腺苷及其类似物以浓度依赖的方式增强了河豚毒素（TTX）对神经传导的抑制作用。效力顺序为：CHA＞D-PIA＞L-PIA＞N6-甲基腺苷＞2-氯腺苷＞腺苷。腺苷代谢产物肌苷和次黄嘌呤对TTX诱导的轴突阻滞无作用。腺嘌呤增强了TTX对神经传导的抑制作用，但效果不如腺苷。db环磷酸腺苷而非环磷酸腺苷模拟了腺苷对神经传导的抑制作用。甲基黄嘌呤不拮抗腺苷对TTX诱导的轴突阻滞的作用，且在高浓度时也模拟了腺苷对神经传导的作用。讨论了腺苷通过与腺苷酸环化酶正偶联的腺苷受体作用于TTX诱导的轴突阻滞的可能性。
