MEDIATION OF CALCITONIN-GENE-RELATED PEPTIDE IN PROTECTION OF ISCHEMIC PRECONDITIONING IN AT HINDLIMBS

AIM: To study modulation of calcitonin gene-related peptide (CGRP) in the protective effect of ischemic preconditioning on endothelial cells . METHODS: Rat hindlmbs were subjected to ischemia for 2 h, and endoth elium-dependent vasorelaxation to acetylcholine (ACh) was examined in rat hindlimbs. RESULTS: Two hours of ischemia elicited no effect on va soconstrictor responses to norepinephrine, but markedly impaired vasod ilator responses to ACh. Ischemic preconditioning induced by 5-min aor tic occlusion and 10-min blood reperfusion prevented the impairment of vasorelaxation to ACh due to long-term ischemia. The protection of is chemic preconditioning was abolished by repeated pretreatments with ca psaicin to deplete CGRP. Acute application of capsaicin to evoke CGRP release or CGRP caused an ischemic preconditioning-like protection, CO NCLUSION: Cap: saicin-sensitive sensory nerves are involved in the pro tective effect of ischemic preconditioning on endothelial cells in the rat hindlimbs, and CGRP can mimic the protective effect of ischemic p reconditioning in blood vessels.