[The nonuniform sensitivity of the cerebral vessels to serotonin].

With serotonin, cerebral blood flow decreased to a great degree during multiple injections. Serotonin was found to produce different effects on brain arterial vessels. It enhanced the resistance of carotid arteries to a greater degree than that in the cerebrobasilar system. Serotonin constricted pial arterioles with an initial diameter of more than 40 nm, whereas the microvessels of less diameter got substantially dilated. The agent had a depriming effect on somatosympathetic and vasomotor reflexes via its interaction with central noradrenergic structures.