ABSTRACT
The sensitivity of smooth muscle cells' adrenoreceptors to noradrenaline (NA) and dopamine (DA) was studied in intact and desympathised arterial microvessels of the rabbit mesentery. The arterioles differed from each other in their sensitivity to catecholamines depending on their diameter. However, in conditions of chemical desympathisation, the sensitivity to NA and DA increased in all the microvessels whereas the degree of narrowing of the microvessels' lumen remained practically the same. These findings suggest a heterogeneous character of physiological properties of vascular smooth muscle cells within the arterial part of the microcirculatory module of the rabbit mesentery.
Subject(s)
Catecholamines/pharmacology , Mesentery/drug effects , Muscle, Smooth, Vascular/drug effects , Sympathetic Nervous System/drug effects , Animals , Arterioles/drug effects , Arterioles/innervation , Arterioles/physiology , Mesentery/blood supply , Mesentery/innervation , Microinjections , Muscle, Smooth, Vascular/innervation , Muscle, Smooth, Vascular/physiology , Oxidopamine , Rabbits , Sympathectomy, Chemical , Sympathetic Nervous System/physiologyABSTRACT
Television microscopic studies have been made of the reaction of mesenterial metarterioles to noradrenalin in newborn, 10- and 30-day rabbits. The results obtained show the existence of postnatal changes in the reactivity of arterioles with a diameter 20-25 mu. Within the period investigated, noradrenalin sensitivity of metarterioles decreases whereas their contractile activity increases. It is suggested that formation of functional properties of metarterioles is not accomplished to the birth of rabbits.
