Mammen G J, Pennefather J N
Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
Agents Actions. 1988 Jun;24(1-2):49-55. doi: 10.1007/BF01968079.
The effects of histamine have been studied on separated circular and longitudinal myometrial layers from the guinea-pig. Virgin guinea-pigs in dioestrus were (1) untreated, (2) treated for 14 days thrice weekly with oestradiol cypionate 20 micrograms/kg s.c., or (3) treated as in (2) but in addition with progesterone 3 mg/animal s.c. daily for 4 days before use. Preparations were field-stimulated (60 V 2 ms 30 Hz for 5 s every 100 s) to elicit regular contractions. Histamine was equipotent in producing enhancement of evoked contractions of circular myometrium from animals in each treatment group (pD2 = 5.03, 5.05 and 4.95 in groups 1, 2 & 3 respectively), and enhanced contractility in all but two longitudinal myometrial preparations. Treatment with oestradiol alone, and with oestradiol and progesterone following oestradiol priming enhanced the magnitude of maximal response and produced a small decrease in the potency of histamine on the longitudinal myometrium. pA2 estimates for mepyramine as an antagonist were similar (8.6) in preparations of longitudinal myometrium from each group of animals. Metiamide (1-10 mumol/l) did not antagonise the effects of histamine in this layer. These results, taken together, indicate that ovarian steroids act selectively on the longitudinal myometrial layer to amplify the action of histamine, but do not alter the histamine receptor subtype which in this layer is exclusively H1.
已对豚鼠离体子宫肌层的环形和纵形肌层进行了组胺作用的研究。处于间情期的未孕豚鼠分为三组：（1）未处理组；（2）每周三次皮下注射20微克/千克环丙孕酮，共处理14天；（3）处理方式同（2），但在使用前4天，每天额外皮下注射3毫克/只孕酮。制备的子宫肌层标本通过场刺激（60伏，2毫秒，30赫兹，每100秒刺激5秒）引发规律性收缩。组胺对各处理组动物环形子宫肌层诱发收缩的增强作用相当（第1、2、3组的pD2分别为5.03、5.05和4.95），并且除两份纵形子宫肌层标本外，组胺增强了所有纵形子宫肌层标本的收缩力。单独使用雌二醇以及雌二醇预处理后联合使用雌二醇和孕酮，均可增强最大反应幅度，并使组胺对纵形子宫肌层的效力略有降低。各组动物纵形子宫肌层标本中，作为拮抗剂的甲氧苄二胺的pA2估计值相似（8.6）。甲硫米特（1 - 10微摩尔/升）对该肌层组胺的作用无拮抗作用。综合这些结果表明，卵巢类固醇选择性作用于纵形子宫肌层以放大组胺的作用，但不改变该肌层中仅为H1型的组胺受体亚型。
