RT Journal Article
SR Electronic
T1 ANALYSIS OF RESERPINE-INDUCED SUPERSENSITIVITY IN AORTIC STRIPS OF RABBITS
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 127
OP 135
VO 177
IS 1
A1 TAYLOR, JOHN
A1 GREEN, RICHARD D.
YR 1971
UL http://jpet.aspetjournals.org/content/177/1/127.abstract
AB In 1966, Hudgins and Fleming (J. Pharmacol. Exp. Ther. 153: 70-80, 1966) reported that aortic strips from rabbits pretreated with reserpine exhibit what they term a "relatively nonspecific supersensitivity," i.e., the strips are supersensitive to l-norepinephrine, acetylcholine and KCl but not to histamine, 5-hydroxytryptamine and angiotensin amide. The present report is an attempt to further delineate the mechanism of this type of supersensitivity. Strips of intima-media from control and reserpine-pretreated animals were prepared by the method of Maxwell et al. (J. Pharmacol. Exp. Ther. 161: 34-39, 1968). Strips from pretreated animals were supersensitive to phenylephrine, acetylcholine and KCl but not to histamine. The dissociation constant (KB) of phentolamine was determined and found to be the same in normal and supersensitive strips. The efficacy (e) but not the dissociation constant (KA) of phenylephrine was changed in the supersensitive state. The maximum response to acetylcholine was increased in strips from reserpine-pretreated animals; the maximum response to phenylephrine was unaffected. In addition, reserpine pretreatment produced an increase in the sensitivity of whole aortic strips to Ba++. These results are interpreted to indicate that this type of supersensitivity is not the result of a presynaptic change or qualitative differences in drug receptors but is the result of either quantitative changes in receptors or, as proposed by Hudgins and Fleming (1966), a change beyond the level of the drug receptor, i.e., in the physiology of the smooth muscle. © 1971, by The Williams & Wilkins Company