H1受体阻断药物对青蛙缝匠肌神经肌肉接头的作用。
Effects of H1-receptor blocking drugs on the frog sartorius neuromuscular junction.
作者信息
Katayama S, Tasaka K
出版信息
Br J Pharmacol. 1985 Aug;85(4):747-53. doi: 10.1111/j.1476-5381.1985.tb11072.x.
The effects of H1-receptor blocking agents, pyrilamine, promethazine, and diphenhydramine, on the amplitude and time course of endplate potentials (e.p.ps) were studied in the sartorius muscles of frogs. H1-receptor blockers (10(-5)-10(-4) M) reduced the amplitude of e.p.ps recorded intracellularly without affecting the resting membrane potential. The acetylcholine potential was decreased by perfusion of H1-receptor blockers. However, when the muscle fibre was stimulated directly, threshold and magnitude of action potential were not affected by H1-receptor blockers. The time constant of decay of the e.p.ps recorded extracellularly was reduced by H1-receptor blockers and the decay remained exponential with a single time constant. The quantal content was not reduced by perfusion of H1-receptor blockers at a concentration of 10(-4) M. It is assumed that the major site of action of these H1-receptor blocking agents is at the postsynaptic membrane.
在青蛙的缝匠肌中研究了H1受体阻断剂、吡苄明、异丙嗪和苯海拉明对终板电位（e.p.ps）幅度和时程的影响。H1受体阻断剂（10⁻⁵ - 10⁻⁴ M）可降低细胞内记录的e.p.ps幅度，而不影响静息膜电位。通过灌注H1受体阻断剂可使乙酰胆碱电位降低。然而，当直接刺激肌纤维时，动作电位的阈值和幅度不受H1受体阻断剂影响。H1受体阻断剂可降低细胞外记录的e.p.ps的衰减时间常数，且衰减保持为具有单一时间常数的指数形式。在10⁻⁴ M浓度下灌注H1受体阻断剂不会降低量子含量。据推测，这些H1受体阻断剂的主要作用位点在突触后膜。
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