Histamine mediates the muscle layer-specific responses in the isolated swine myometrium

摘要: To clarify the role of histamine in uterine contractility, effect this biogenic amine on myometrium cyclic mature gilts was investigated by an isometric tension recording study vitro. In addition, using crude membrane preparations isolated from longitudinal (LM) and circular muscle (CM), distribution H1 receptors characterized 3H-pyrilamine binding assay. Histamine caused a tetrodotoxin-resistant contractile response LM CM Krebs solution, but (-logEC50 = 6.34) more sensitive than 5.4). Pyrilamine decreased excitatory both layers. pyrilamine-treated LM, high concentration (1-30 microM) slight inhibition spontaneous contraction, abolished ranitidine. On other hand, did not cause any preparations. Dimaprit (10-300 concentration-dependently inhibited contraction CM. presence pyrilamine ranitidine, N alpha-methylhistamine, even at 10 microM, affect electrical field stimulation (5Hz)-induced Specific sites were distributed heterogeneously swine myometrium. The maximum number (132.5 +/- 9.9 fmol/mg protein, n 10) 2.5 times higher that (52.2 3.2 6). These results indicate there is layer-dependent difference histamine-induced layer, acts H2 receptors, causes (via low concentration) or relaxation pyrilamine). However, only likely result absence receptors. Histamine-induced conspicuous because heterogeneous H1-receptors between