Journal of the autonomic nervous system
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J. Auton. Nerv. Syst. · May 1982
Effect of ketamine, althesin, and thiopentone on the Valsalva-constrictor and heart rate reflexes of the rabbit.
The circulatory effects of Valsalva-like manoeuvers were studied before and during i.v. infusions of either ketamine, Althesin and thiopentone given in doses that produced similar levels of light anesthesia. The Valsalva-like manoeuvers were of 30 s duration and consisted of applying Valsalva pressures (VP) from 2.5 to 20 mm Hg to the animal's respiratory valve and to a cuff placed around its thorax and abdomen. ⋯ Ketamine and thiopentone produced marked depression of the Valsalva-heart rate reflex, but Althesin had relatively little effect. We concluded that ketamine produces greater impairment of blood pressure homeostasis mediated through constrictor and heart rate reflexes evoked through arterial and cardiopulmonary baroreceptors than the other two anesthetics.