Poli E, Coruzzi G, Bertaccini G
Institute of Pharmacology, University of Parma, Italy.
J Pharmacol Methods. 1990 Jul;23(4):265-74. doi: 10.1016/0160-5402(90)90055-p.
The effect of changes in the composition of the bathing medium on the effect of histamine and histamine H2-receptor antagonists was investigated in the isolated guinea pig papillary muscle. Ringer or Krebs-Henseleit solutions were used as nutrient fluids. They mainly differed with respect to pH and to Mg2+ and H2 PO4- content. Whereas the effect of histamine was not altered by ionic changes, the antagonism by some H2 blockers was different in the two nutrient solutions. The insurmountable antagonism elicited by high concentrations (greater than or equal to 10(-6) M) of famotidine, oxmetidine and mifentidine in Ringer solution was converted to surmountable when these drugs were tested in Krebs-Henseleit solution. Conversely, the antagonism induced by ranitidine was surmountable in both solutions, and that induced by high amounts of Ioxtidine was insurmountable in both nutrient fluids. Results obtained in Ringer solution were not modified by pH adjustments or by the addition of ions present in Krebs-Henseleit medium. These results suggest that the interaction of histamine with H2 receptors in the guinea pig papillary muscle was not influenced by alterations in the ionic composition of the nutrient fluid, whereas the antagonism may be critically dependent on the ionic environment.
在离体豚鼠乳头肌中研究了浴液成分变化对组胺及组胺H2受体拮抗剂作用的影响。使用林格氏液或克雷布斯 - 亨泽莱特液作为营养液。它们主要在pH值以及镁离子和磷酸二氢根离子含量方面存在差异。虽然组胺的作用不会因离子变化而改变，但在两种营养液中，某些H2受体阻滞剂的拮抗作用有所不同。在林格氏液中，高浓度（大于或等于10(-6) M）的法莫替丁、奥美替丁和米芬替丁引发的不可克服的拮抗作用，在克雷布斯 - 亨泽莱特液中测试时转变为可克服的。相反，雷尼替丁诱导的拮抗作用在两种溶液中都是可克服的，而高剂量碘替丁诱导的拮抗作用在两种营养液中都是不可克服的。在林格氏液中获得的结果不会因pH值调整或添加克雷布斯 - 亨泽莱特液中的离子而改变。这些结果表明，豚鼠乳头肌中组胺与H2受体的相互作用不受营养液离子组成变化的影响，而拮抗作用可能严重依赖于离子环境。
