pituitrin and Muscle-Rigidity

The mechanical effect of acute decerebrate rigidity upon the ICP and the mechanisms underlying the relationship between them have been investigated with experiments performed on 26 cats. It has been shown that: a) Extreme rigidity of the peripheral musculature with or without partial activation of the trunkal muscles produces no change in ICP, b) the simultaneous elevation of the intra-thoracic and intra-abdominal pressures is the factor primarily operative in raising and maintaining the elevated ICP, c) when cerebrovascular homeostasis is already defective a subsidiary but not unimportant role is played by the elevation of the systemic arterial pressure, d) under conditions of normal brain elastance mild and short-lasting spasms produce no effect on the ICP. In an animal, however, in which the brain elastance had been increased by inflating a small air-filled balloon, similar spasms produced a marked increase in ICP.

Topics: Animals; Bicarbonates; Blood Pressure; Carbon Dioxide; Cats; Cerebrovascular Circulation; Decerebrate State; Dominance, Cerebral; Intracranial Pressure; Jugular Veins; Mesencephalon; Muscle Rigidity; Muscle Spasticity; Oxygen; Respiration; Vasopressins

Topics: Animals; Arteries; Cats; Epinephrine; Femoral Artery; Hepatic Artery; Mesenteric Arteries; Muscle Contraction; Muscle Rigidity; Muscle, Smooth; Norepinephrine; Phenylephrine; Renal Artery; Splenic Artery; Stimulation, Chemical; Vasopressins