Wilson C, Broadley K J
Can J Physiol Pharmacol. 1980 Feb;58(2):167-73. doi: 10.1139/y80-027.
The positive chronotropic responses of guinea pig isolated right atria to histamine were antagonized by metiamide (pA2, 5.95) thus confirming their H2 receptor classification. The positive inotropic responses of paced left atria were antagonized to some extent by mepyramine to give a pA2 value of 7.87, indicating the involvement of H1 receptors. A limit to the shift of cumulative dose-response curves for the inotropic response suggested an H1 receptor resistant component. The inotropic response to sequentially administered histamine was biphasic. On lowering the temperature to 25 degrees C, the two components became more demarcated and separated by a negative phase. Only the primary positive component and the negative component were antagonized by mepyramine. At 38 degrees C, the response was similarly converted to a monophasic one. The residual responses were resistant to metiamide and propranolol antagonism and therefore not mediated via H1, H2, or beta-adrenergic receptors.
甲硫米特可拮抗豚鼠离体右心房对组胺的正性变时反应（pA2，5.95），从而证实其H2受体分类。普萘洛尔对起搏左心房的正性变力反应有一定程度的拮抗作用，pA2值为7.87，表明H1受体参与其中。变力反应累积剂量-反应曲线的位移受限提示存在H1受体抗性成分。对依次给予组胺的变力反应呈双相性。将温度降至25℃时，两个成分变得更加分明，并被一个负相分隔。只有初级正性成分和负性成分被普萘洛尔拮抗。在38℃时，反应同样转变为单相反应。残余反应对甲硫米特和普萘洛尔的拮抗作用具有抗性，因此不是通过H1、H2或β-肾上腺素能受体介导的。
