组胺对去极化大鼠子宫的某些作用。

Some effects of histamine in the depolarized rat uterus.

Blyth D I

Br J Pharmacol. 1973 Nov;49(3):445-56. doi: 10.1111/j.1476-5381.1973.tb17255.x.

Abstract

The relaxant effect of histamine in the isolated rat uterus remained after the preparation was depolarized in a potassium Ringer.2. The effect was abolished by the calcium-chelating agent, ethyleneglycol bis-aminoethyl ether-tetraacetic acid (EGTA).3. Histamine caused relaxation during calcium-induced contractures in a depolarized uterus treated with EGTA, but did not produce relaxation during barium-induced contractures.4. While responses of a normally polarized rat uterus to acetylcholine were inhibited by histamine, those of a depolarized uterus were enhanced by histamine. The inhibitory effects of isoprenaline and papaverine on acetylcholine responses were maintained in depolarized preparations.5. Both the enhancing effect of histamine on responses to acetylcholine and the relaxation of calcium-induced contractures were abolished by burimamide, indicating that H(2)-receptors mediate the effects of histamine in the depolarized tissue.6. A reduction in the rate of exchange of calcium across the depolarized cell membrane was demonstrated with high concentrations of histamine.7. The results are consistent with the hypothesis that in the rat uterus, the stimulation of H(2)-receptors by histamine is accompanied by a reduction in calcium exchange across the membrane which may result in a decrease in the concentration of free intracellular calcium available to stimulate contraction of the myofilaments. Histamine may act by increasing the binding of calcium within the cell.

摘要

在钾离子林格液中使制备的离体大鼠子宫去极化后，组胺的松弛作用依然存在。
该作用被钙螯合剂乙二醇双氨基乙醚四乙酸（EGTA）消除。
在经EGTA处理的去极化子宫中，组胺在钙诱导的挛缩过程中引起松弛，但在钡诱导的挛缩过程中不产生松弛。
正常极化的大鼠子宫对乙酰胆碱的反应受组胺抑制，而去极化子宫对乙酰胆碱的反应则被组胺增强。异丙肾上腺素和罂粟碱对乙酰胆碱反应的抑制作用在去极化制剂中得以维持。
组胺对乙酰胆碱反应的增强作用以及对钙诱导挛缩的松弛作用均被布立马胺消除，这表明H₂受体介导了组胺在去极化组织中的作用。
高浓度组胺可使去极化细胞膜上的钙交换速率降低。
这些结果与以下假设一致：在大鼠子宫中，组胺对H₂受体的刺激伴随着跨膜钙交换的减少，这可能导致可用于刺激肌丝收缩的细胞内游离钙浓度降低。组胺可能通过增加细胞内钙的结合起作用。