Abstract
Arterial smooth muscle response to direct electrical stimulation or stimulation of sciatic nerve, has been studied on the tibial artery of the dog. A segment of this artery was catheterized in two points separated by about 5 cm. Response of this segment to stimulation has been studied at constant arterial volume and at constant arterial flow-rate.
At constant arterial volume, initial pressure was adjusted between 25 to 120 mm Hg. Direct electrical stimulation was always followed by an important arterial pressure increase (158 to 183 mm Hg). Stimulation of the sciatic nerve also provoked an important increase of pressure (150 to 177 mm Hg).
At constant perfusion flow-rate, the pressure of the arterial segment was adjusted from 50 to 250 mm Hg (flow-rates included between 10 to 20 ml/min.). Direct stimulation was followed by a maximal vaso-constriction. Initial pressures of 50, 100, 150, 200 or 250 mm Hg all yielded very similar values (217 ± 17 mm Hg). Stimulation of the sciatic nerve produced an increase of pressure to 272 ± 17 mm Hg with a different response chronology.
These results show that, on tibial artery (generally considered as musculoelastic), smooth vascular muscle may considerably modify the hemo-dynamic conditions.
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