【摘要】 在单个大鼠肾上腺嗜铬细胞上，用显微荧光测量和碳纤电极记录方法，测量可激活毒草碱（muscarine，M）受体的激动剂乙酰甲胆碱（methachaoline，MCh）对胞内游离钙浓度[Ca2+]i和儿茶酚胺激素分泌的影响。在细胞外液含2mmol／LCa2+时，用含钙或不含钙的MCh（1mmol/L）刺激细胞，均引起[Ca2+]i的升高或钙振荡，并诱发激素的分泌。细胞外液不含Ca2+时，以类似方式施加MCh刺激也引起[Ca2+]i的升高和激素分泌。这些资料表明，激发嗜钻细胞毒蕈碱受体可引起钙库释放，并触发分泌。在无外钙条件下，还研究了连续刺激引起的[Ca2+]i变化，发现第一次的1mmol/LMCh刺激可升高[Ca2+]i，但与细胞外液中含Ca2+时不同的是，细胞对随后的MCh刺激不再响应。这表明，在无外Ca2+时，细胞内Ca2+库可以被单次MCh刺激所排空。更多还原

【Abstract】 In rat single athenal cboedn cells, the effects of methacholine (MCh) on[ Ca2+ ]i and catecholthene secrehon were stUdied with fura-2 fluorescence and carbonfther elecwhes. In the presence of 2 InmchL Ca2 + in the bath, locally applving 1 mmol/L MCh, either contalning or not contalning Ca2+, evoked b0th [ Ca2+ ]i and secretionsignals. In the ahsence of Ca2+ in the bath, MCh could shll evoke [ Ca2+ ]i andsecrehon . These restilts suggest tha MCh causes release of Ca2+ ffom Ca2 + stores, Whichis sufficient to yteld the evoked secreh0n. The Ca2+ store can be depleted by single MChpnff in the absence of Ca2+ in the bath.更多还原