Swales L S, Evans P D
Department of Zoology, University of Cambridge, England.
Histochemistry. 1988;90(3):233-9. doi: 10.1007/BF00492512.
A histochemical technique for the localization of adenylate cyclase activity has been applied to the extensor-tibiae muscle of the hindleg of the locust, Schistocerca gregaria to localise the sites of action of the modulatory compounds octopamine and proctolin. Octopamine-sensitive adenylate cyclase activity can be demonstrated in fast and intermediate type muscle fibres but not in the limited number of purely slow muscle fibres (3-6) in the fan region at the proximal end of the muscle. In contrast the latter fibres are the only ones in the muscle to exhibit proctolin-sensitive adenylate cyclase activity. In both cases the bulk of the reaction product is localised in the sarcoplasmic reticulum component of the dyads, with lesser amounts occurring beneath the sarcolemmal membrane, in the non-dyad sarcoplasmic reticulum and in the T-tubule system. The results are consistent with physiological data suggesting that proctolin, but not octopamine, mediates its effects on the myogenic rhythm of contraction and relaxation in this muscle by changing the levels of cyclic AMP in the small group of slow muscle fibres which act as the pacemaker for this rhythm.
一种用于定位腺苷酸环化酶活性的组织化学技术已应用于蝗虫（沙漠蝗）后足胫节伸肌，以定位调节化合物章鱼胺和促肠肌肽的作用位点。在快速和中间型肌纤维中可显示出对章鱼胺敏感的腺苷酸环化酶活性，但在肌肉近端扇形区域数量有限的纯慢肌纤维（3 - 6根）中则未显示。相反，后一种纤维是肌肉中唯一表现出对促肠肌肽敏感的腺苷酸环化酶活性的纤维。在这两种情况下，大部分反应产物都定位于二联体的肌浆网成分中，在肌膜下、非二联体肌浆网和T小管系统中的含量较少。这些结果与生理学数据一致，表明促肠肌肽而非章鱼胺，通过改变作为该节律起搏器的一小群慢肌纤维中的环磷酸腺苷水平，来介导其对该肌肉收缩和舒张肌源性节律的影响。
