DIFFERENT LEVELS OF SENSORY NEUROPEPTIDES (CALCITONIN-GENE-RELATED PEPTIDE AND SUBSTANCE-P) DURING AND AFTER EXERCISE IN MAN

The aim of this study was to investigate the regulation of two sensory peptides calcitonin gene-related peptide (CGRP) and substance P, refl ected as circulating levels during provocation of the sympathetic nerv ous system. Levels in hypertensives, diabetics (NIDDM) and controls we re assayed before, during and after an exercise test (average work loa d carried out was 76 +/- 10 kJ). CGRP levels increased progressively d uring exercise (P < 0.001), with maximum level at maximum exercise. Th is was significant in all three groups; hypertensives P < 0.001, diabe tics P < 0.01 and controls P < 0.001. No differences in circulating re vels of CGRP between the three groups were found. Substance P levels w ere fairly constant during exercise but increased 30 min after exercis e (P < 0.01) in the total group. We hypothesize that CGRP might provid e a counterregulatory mechanism to the sympathetic vasoconstrictor tra nsmitters noradrenaline (NA) and neuropeptide Y (NPY) during sympathet ic activation. Substance P did not increase during exercise. This sugg ests differential regulation and function of the two vasodilatory pept ides.