Ultrastructure of the innervation of the cat lingual artery in relation to noradrenergic vasoconstriction, and to neurogenic vasodilation produced by cholinergic and nonadrenergic, noncholinergic mechanisms.

The lingual artery is one of several arteries in the head of the cat which have been found to contain both a noradrenergic neural vasoconstrictor mechanism, and neural vasodilator mechanisms which appear to utilize acetylcholine as well as a second neurotransmitter (possibly a peptide). In this study, after fixation of lingual arteries by the chromaffin method, both adrenergic and noradrenergic nerves were found at the adventitiomedial border and within the outer third of the tunica media. All of the nonadrenergic nerves had a similar structural appearance, containing mostly small clear vesicles. There may be a single population of dilator nerves containing both acetylcholine and a second transmitter, or there may be two populations of dilator nerves with the same structure, each containing a different transmitter.