The peptidergic innervation of human coronary and cerebral vessels.

It is now well established that in addition to nerves containing classical transmitters, the mammalian vascular system is also supplied by nerve fibre subpopulations containing several vasoactive peptides. The precise function of these peptides (neuropeptide Y, calcitonin gene-related peptide, vasoactive intestinal polypeptide, somatostatin and the tachykinins) is still unknown, however, their widespread occurrence in perivascular nerves indicates that they are likely candidates for a role in the neurogenic regulation of the vascular system. It has been suggested that they may exert a direct vasomotor action via their own receptors and/or modulate the release and action of other vascular transmitters. Recently, several studies have focused on the supply of nerve fibres storing neuropeptides in the coronary and cerebral vasculature of laboratory animals, however, little is known on the distribution of these putative transmitters in human coronary and cerebral vessels. In this paper, the immunocytochemical evidence that several neuropeptides are localized in subpopulations of afferent and efferent nerve fibres supplying the human coronary and cerebral vasculature is focused.