The effect of vasoactive intestinal peptide (VIP) on the nerve-stimulated contraction, tissue oxygenation, lipid peroxidation and antioxidant enzymes activities-superoxide dismutase and catalase was investigated in the rat gastrocnemius muscle exposed to 4 h ischemia-4hr reperfusion. Ischemia caused significant decrease in muscle contractile force, oxygenation and superoxide dismutase enzyme activity. Reperfusion of ischemic muscle increased the muscle contractile force and restored the tissue oxygenation to the baseline lever. Superoxide dismutase and catalase activities of reperfused muscle increased significantly. However neither ischemia nor reperfusion affected gastrocnemius muscle malondialdehide (MDA) levels. VIP administration at the onset of reperfusion significantly increased skeletal muscle contractile force and tissue oxygenation even higher than baseline and reperfusion values. VIP also normalized the increased superoxide dismutase and catalase activities of reperfused skeletal muscle. In conclusion, VIP, acting as a powerful antioxidant and preserving contractile machinery seems to be a promising endogenous peptide that can salvage the skeletal muscle from severe ischemia-reperfusion injury. (C) 1997 Elsevier Science Inc.