RT Journal Article
SR Electronic
T1 LOCAL AND NEURALLY MEDIATED EFFECTS OF MORPHINE ON SKELETAL MUSCLE VASCULAR RESISTANCE
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 359
OP 367
VO 180
IS 2
A1 Edward Lowenstein
A1 Richard B. Whiting
A1 David A. Bittar
A1 Charles A. Sanders
A1 William John Powell, Jr.
YR 1972
UL http://jpet.aspetjournals.org/content/180/2/359.abstract
AB Morphine caused both a local and a neurally mediated decrease in skeletal muscle vascular resistance of the isolated canine gracilis muscle preparation which was separately perfused with blood at a near constant flow. The local (gracilis artery injection, acutely denervated muscle) decrease was consistent, dose-dependent and reversible with time. An initial, transient neurally mediated (systemic i.v. injection, innervated muscle) decrease in vascular resistance was present if control resistance was higher than denervated resistance. This decrease appeared secondary to central sympatholysis or ganglionic sympathetic blockade, since it was unaffected by cholinergic blockade, cervical vagotomy or carotid sinus denervation but was absent if control resistance approximated denervated vascular resistance or if the muscle had received a previous alpha adrenergic receptor blockade. A sustained elevation of muscle vascular resistance of the innervated muscle occurred regardless of whether or not the initial neurally mediated decrease was present. Presumably this represented a reflex compensation for the direct local vasodilatory effect of morphine. These data suggest central withdrawal of vasomotor tone as a mechanism for the hypotension after morphine administration and may explain the variable peripheral circulatory response to morphine observed clinically. © 1972 by The Williams & Wilkins Co.