嘌呤核苷酸与“嘌呤能”神经刺激对豚鼠盲肠带所诱发效应的比较。

A comparison of effects evoked in guinea-pig taenia caecum by purine nucleotides and by "purinergic" nerve stimulation.

Jager L P, Schevers J A

J Physiol. 1980 Feb;299:75-83. doi: 10.1113/jphysiol.1980.sp013111.

Abstract

Effects of adenosine and the adenosine nucleotides (ATP, ADP, AMP and CoA) on the guinea-pig taenia caecum were studied by measuring simultaneously the changes in membrane potential and in contractility induced by these agents using the sucrose-gap technique.2. In the presence of carbachol (5 x 10(-8)M) the hyperpolarization and the relaxation induced by these agents was found to be closely correlated. Their different potencies suggested an action on the P(2) type purinoceptor: ATP >/= ADP >/= AMP > CoA > AD.3. The transmitter released endogenously in the presence of carbachol (5 x 10(-8)M) by the non-adrenergic inhibitory (n.a.i.) nerves after half-maximal stimulation induced an inhibitory junction potential (i.j.p.) which transiently counteracted the carbachol-induced depolarization. This i.j.p. was mimicked by ATP, ADP, and AMP applied exogenously in concentrations of about 3 x 10(-5)M, by CoA (3 x 10(-4)M) and by adenosine (3 x 10(-3)M).4. The results presented are in agreement with the hypothesis that the transmitter substance released by the n.a.i. nerves is a purine nucleotide, which in the guinea-pig taenia caecum affects the smooth muscle cell membrane via the P(2)-purinoceptor. Of the putative transmitters studied, ATP, ADP and AMP seem the most likely.

摘要

采用蔗糖间隙技术，通过同时测量豚鼠盲肠带的膜电位变化和这些药物诱导的收缩性变化，研究了腺苷及腺苷核苷酸（ATP、ADP、AMP和辅酶A）对豚鼠盲肠带的作用。
在存在卡巴胆碱（5×10⁻⁸M）的情况下，发现这些药物诱导的超极化和松弛密切相关。它们不同的效力表明对P₂型嘌呤受体有作用：ATP≥ADP≥AMP＞辅酶A＞腺苷。
在半最大刺激后，非肾上腺素能抑制（n.a.i.）神经在存在卡巴胆碱（5×10⁻⁸M）时内源性释放的递质诱导了抑制性接头电位（i.j.p.），该电位短暂抵消了卡巴胆碱诱导的去极化。外源性施加浓度约为3×10⁻⁵M的ATP、ADP和AMP、3×10⁻⁴M的辅酶A以及3×10⁻³M的腺苷可模拟这种i.j.p.。
所呈现的结果与以下假设一致，即n.a.i.神经释放的递质物质是一种嘌呤核苷酸，在豚鼠盲肠带中它通过P₂嘌呤受体影响平滑肌细胞膜。在所研究的假定递质中，ATP、ADP和AMP似乎最有可能。