[Role of receptor transactivation in the cardioprotective effects of preconditioning and postconditioning]

Analysis of published data indicates that the activity of receptors for adenosine, opioids, bradykinin, calcitonin-gene related peptides (CGRP) and epidermal growth factor (EGF) play important role in triggering the cardioprotective effects of ischemic preconditioning. Cannabinoids mimic the infarct-sparing effects of preconditioning. Endogenous adenosine, opioids, bradykinin and CGRP have also been implicated in infarct-reduction with ischemic postconditioning. Again, cannabinoids also mimic the protective effect of postconditioning. Recent works support heterodimerization of G-protein coupled receptors (GPCRs), and GPCR transactivation of EGF receptors. It was found that cross-talk between delta(j)-opioid receptors and adenosine A(1)-receptors is essential to cardiac protection. Furthermore, evidence implicates EGF receptor transactivation in cardioprotective effect of multiple GPCrs including adenosine, acetylcholine, bradykinin, and opioid receptors. Such findings support a convergent pathway in which multiple GPCRs may interact (or function independently) to transactivate EGF receptor-dependent kinase signaling and cytoprotection.