Aim Calcitonin gene-related peptide (CGRP), a princlpal transmitter in cardiac and vascular sensory nerves, is released from the heart during ischemia,which protected the myocardium against ischemia-reperfusion injury in isolated rat hearts. The purpose of this study was to investigate whether CGRP-induced preconditioning has cardioprotective effects in intact rat hearts.Methods 36 SD rats were at random divided into three groups of control, ischemic preconditioning (IPC) and CGRP. CGRP (10 μg/kg) was given 20min before 30 min ischemia. All animals were .sub-jected to 30 min of regional ischemia followed by 2 h of reperfusion. The preconditioning protocol consisted of 3 cycles of 5 min regional ischemia and 3 cycles of 5min of reperfusion. Infarct size as a percentage of the area at risk was determined with nitro blue tetrazoli-um.Results Both of IPC and CGRP-induced precondi-tioning markedly reduced the incidences of ventricular arrhythmias during ischemia and reperfusion. Both ofIPC (15. 7%, P< 0. 01) and CGRP-induced precondi-tioning (28. 8%, P<0.01) also resulted in a signifi-cant reduction in infarct size when compared to control(54. 0%).Conclusion These results support the hypothesis that CGRP-induced preconditioning has cardoprotective effects in intact rat hearts.