P2嘌呤受体激动剂对豚鼠离体门静脉的作用。
The effects of P2 purinoceptor agonists on the isolated portal vein of the guinea pig.
作者信息
Orre M, Pennefather J N, Story M E, Haynes J M
机构信息
Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
出版信息
Eur J Pharmacol. 1996 Dec 5;316(2-3):229-36. doi: 10.1016/s0014-2999(96)00687-5.
UTP, ATP and several of its analogues enhanced contractions of the longitudinal smooth muscle layer of the guinea-pig portal vein. The rank order of potency was 2-methylthioATP > alpha, beta-methyleneATP > adenosine tetraphosphate > or = beta, gamma-methyleneATP > or = ATP = UTP > > adenosine. Suramin (100 microM) blocked the contractile effects of 2-methylthioATP and alpha,beta-methyleneATP, but not those of ATP and adenosine tetraphosphate. The P1 purinoceptor antagonist, 8-phenyltheophylline (10 microM), was without effect on the response to ATP. Field stimulation (5 s trains every 100 s, 1 ms, 55 V) caused frequency-dependent contractions that were partially reduced by the noradrenergic neurone blocking drug; BW 172C58 (4-benzoyl-xylocholine, 10 microM), but not by suramin. alpha,beta-MethyleneATP was more potent than beta,gamma-methyleneATP, UTP and adenosine tetraphosphate in partially inhibiting field stimulation-induced contractions of the portal vein; its effects, but not those of adenosine tetraphosphate, were reduced by suramin. These results indicate that the guinea-pig portal vein contains P2 purinoceptors; these include a P2x subtype, mediating contraction.
尿苷三磷酸（UTP）、三磷酸腺苷（ATP）及其几种类似物增强了豚鼠门静脉纵行平滑肌层的收缩。效力顺序为：2-甲硫基三磷酸腺苷＞α,β-亚甲基三磷酸腺苷＞四磷酸腺苷＞或 = β,γ-亚甲基三磷酸腺苷＞或 = 三磷酸腺苷 = 尿苷三磷酸＞＞腺苷。苏拉明（100微摩尔）阻断了2-甲硫基三磷酸腺苷和α,β-亚甲基三磷酸腺苷的收缩作用，但未阻断三磷酸腺苷和四磷酸腺苷的收缩作用。P1嘌呤受体拮抗剂8-苯基茶碱（10微摩尔）对三磷酸腺苷的反应无影响。场刺激（每100秒进行5秒串刺激，1毫秒，55伏）引起频率依赖性收缩，去甲肾上腺素能神经元阻断药物BW 172C58（4-苯甲酰基-木兰花碱，10微摩尔）可部分降低这种收缩，但苏拉明无此作用。在部分抑制门静脉场刺激诱导的收缩方面，α,β-亚甲基三磷酸腺苷比β,γ-亚甲基三磷酸腺苷、尿苷三磷酸和四磷酸腺苷更有效；苏拉明可降低其作用，但不影响四磷酸腺苷的作用。这些结果表明，豚鼠门静脉含有P2嘌呤受体；其中包括介导收缩的P2x亚型。
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