Comparison of Vasoconstrictor Responses in Functionally Different Organs Induced by Stimulation of Mesencephalic Pressor Area

In an attempt to clarify the selective vasoconstriction of different vascularbeds, vasoconstrictor responses of kidney, intestine and lower extremity to the electrical stimulation of the points within the mesencephalon were systematically explored. Three vascular circuits were perfused at constant flow, and changes in vascular resistance were indicated by changes in perfusion pressure. Various points were stimulated by moving electrode position, and systemic arterial pressure and perfusion pressure from 2 of these vascular circuits were simultaneously measured. Central stimulation caused systemic pressor and vasoconstrictor responses of varied degree in 3 vascular circuits. Slight shift in electrode position altered the vasoconstrictor response patterns in these vascular circuits. The points giving maximum systemic pressor and maximum vasoconstrictor responses in kidney, intestine and lower extremity were anatomically separate, though these points were located very closely each other. No anatomical separation was found in control group, both sides of renal or femoral circuits.