On the other hand , a positive inotropic response was induced by il - 2 in isolated rat atria , indirectly by activating myocardial 3 - adrenoceptors by release of catecholamines , and directly by increasing the production of second messenger camp . in the isolated rat heart , stimulation of cardiac k opioid receptors has been shown to induce ventricular ectopic beats and to reduce the force of ventricular contraction 通過(guò)文獻(xiàn)調(diào)研和我們的預(yù)實(shí)驗(yàn),我們假設(shè), il - 2的心臟作用涉及心肌細(xì)胞收縮力和細(xì)胞內(nèi)鈣的變化,其信號(hào)轉(zhuǎn)導(dǎo)途徑可能并非通過(guò)自身受體,而是通過(guò)存在于心肌細(xì)胞膜上的阿片受體發(fā)揮作用的;其對(duì)血管的作用可能循相關(guān)途徑。