[Vasomotor innervation of the arteries and veins of Rana temporaria frogs].

Adrenergic and cholinergic innervation of frog arteries and veins has been studied histochemically using glyoxilic acid and the method of Karnovsky--Roots. It was shown that the vessels studied differ in catecholamine-containing structures, the intensity of fluorescence of adrenergic nerve endings, the density of nervous plexus and the direction of nerve fibers. It was found that adrenergic innervation is present not only in the arteries, but in the veins as well. Morphometrical analysis indicates that the density of adrenergic plexus per volume unit of vascular wall in the veins investigated is higher than the density of adrenergic nerves in the arteries. This finding suggests that the nervous control of the veins appears in evolution beginning from amphibians, but not from reptiles. It was reliably demonstrated that aorta thoracica and pulmonary artery receive cholinergic innervation, the density of cholinergic plexus in the latter being twice higher than that of adrenergic one.