Capsaicin at a concentration of 10-7 M induced a significant increase in heart rate and increased coronary flow in isolated Langendorff-perfused guinea-pig hearts. This effect was completely blocked by 30 μM of Nω-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase. Additional incubation with 3 mM L-Arg antagonized the inhibitory effect of L-NAME. In the presence of 1 μM of a human calcitonin gene-related peptide fragment (hCGRP 8-37), a CGRP-receptor antagonist, L-Arg was without effect. We conclude that a capsaicin-induced increase in coronary flow and heart rate is dependent from an interplay between CGRP and NO in guinea-pig hearts.
- Calcitonin gene-related peptide
- Guinea-pig heart
- Nitric oxide
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