家兔化学裸露心肌标本制备及其张力-pCa关系

家兔右室乳头肌在含3mM EDTA、5mM Na_2ATP、10mM Tris、140 mM KCl的溶液中浸浴150min,其Ca~(2+)通透性显著增高。Ca~(2+)浓度为10~(-7)M时,便可产生张力,10~(-4.6)M时,张力达到最大。相对张力-pCa(Ca~(2+)浓度的负对数)关系近似一S形曲线,产生50％最大张力的Ca~(2+)(pCa_(50))约为10~(-6.6)M。同法制备的大鼠乳头肌Ca~(2+)通透性未见增高。

PREPARATION OF CHEMICALLY SKINNED RABBIT CARDIAC MUSCLE AND ITS TENSION-pCa RELATION

The hyperperm eable rabbit right ventricular papillary muscles were produced by bathing them for 150 minutes in a solution containing 3mM EDTA,5mM Na2ATP.5mM Tris and 140mM KCl,and used to study the Ca++ affinity and Ca ++-sensitivity of the contractile proteins. These hyperpermeable muscles developed some tension at approximately 10-7M Ca++, and achieved maximal tension at 10-4.4 MCa++. They relaxed rapidly when contracture solution was replaced by relaxation solution containing no calcium. The tension developed at a given Ca++ concentration was independent of the order in which contracture solutions containing different amounts of Ca++ had been applied. The relative tension-pCa( negative logarithm of Ca ++ ) relation resembled a sigmoidal curve, and tension equal to half-mixim-um was produced at approximately 10-6.6 M Ca++. The muscles treated with no EDTA developed some tension weakly only at Ca ++ concentrations more than 10-5M. The Ca ++ -permeability of the rat right ventricular papillary prepared by this method did not increase markedly.