[Wall thickness of skeletal muscle microvessels and their reactivity to vasoconstrictor stimuli in normal rats and rats with spontaneous hypertension].
Wall thickness (w), wall thickness to lumen radius ratio (w/r) and vasomotor reactions produced by electrical stimulation of the sympathetic tract were studied by intravital microscopy of the skeletal muscle (extensor hallucis proprius) and compared in normal Wistar rats (NWR) and spontaneously hypertensive rats (SHR). It was established that w and w/r of arterioles with an equal lumen was greater in SHR than in NWR. Sympathetic stimulation with 6 mA, 3 imp/sec for 10 sec produced an almost 50% reduced arteriolar constriction in SHR, as compared to NWR. Linear positive correlation was shown between w/r and the degree of the lumen narrowing in both groups of animals. A bias for the increase in arteriolar response to neurogenic stimuli was manifested after a drop in blood pressure due to an acute hemorrhage in SHR. It is suggested that high blood pressure in SHR ensures the perfusion of the microcirculatory bed with a constant blood volume and prevents arteriolar constriction.
D000818:Animals; D001160:Arterioles / Q000033:anatomy & histology / Q000502:physiology; D001794:Blood Pressure; D004558:Electric Stimulation; D006470:Hemorrhage / Q000503:physiopathology; D009132:Muscles / Q000098:blood supply*; D051381:Rats; D011918:Rats, Inbred SHR / Q000502:physiology*; D011919:Rats, Inbred Strains / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology; D014661:Vasoconstriction
Tolshchina stenki mikrososudov skeletnoĭ myshtsy i ikh reaktivnost' k vazokonstriktornym stimulam u normal'nykh krys i u krys so spontannoĭ gipertonieĭ.