RT Journal Article
SR Electronic
T1 THE SITE OF ACTION OF AHR-2666 IN FROG SARTORIUS MUSCLE
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 156
OP 163
VO 191
IS 1
A1 Karen C. Lustig
A1 Edward B. Kirsten
YR 1974
UL http://jpet.aspetjournals.org/content/191/1/156.abstract
AB AHR-2666, 3-(m-chlorophenoxy)-1-methylearbamoylpyrrolidine, a skeletal muscle relaxant, produces a dose-related, reversible decline in isometric twitch tension. While AHR-2666 (pKa = 0.19 ± 0.04) does not bring about contracture in concentrations of 0.4 to 1.2 mM, it antagonizes both the potassium contracture and contractures produced by the addition of caffeine (7.5-50 mM) to the Ringer's solution. AHR-2666 appears to act as a competitive inhibitor of caffeine in frog sartorius muscle. The increased 45Ca efflux produced by 10 mM caffeine is completely blocked by AHR-2666 (0.4 mM): higher concentrations of caffeine are less completely antagonized. By itself, AHR-2666 has no effect on either the uptake or release of 45Ca from resting muscle. The muscle action potential was inhibited parallel with that of the twitch. The data suggest that the peripheral muscle relaxant effects of AHR-2666 are similar to those of the local anesthetics. © 1974 by The Williams & Wilkins Company