RT Journal Article
SR Electronic
T1 DIFFERENCES IN THE TUBOCURARINE ANTAGONISM OF THE ACTIVATION OF MUSCLE SPINDLE AFFERENTS BY SUCCINYLCHOLINE, ACETYLCHOLINE AND NICOTINE
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 573
OP 584
VO 156
IS 3
A1 Cedric M. Smith
A1 Edson X. Albuquerque
YR 1967
UL http://jpet.aspetjournals.org/content/156/3/573.abstract
AB Oscillographic recordings of the activity of group Ia and II afferent fibers from deefferented muscle spindles in the triceps surae muscle group were carried out in acutely spinalized cats. Smaller doses of i.v. administered tubocurarine (TC) were required to abolish extrafusal neuromuscular transmission than to abolish transmission from fusimotor nerve fibers to intrafusal muscle fibers. After the administration of sufficient TC to abolish fusimotor neuromuscular transmission the stimulation of the group Ia or II afferent discharge induced by succinylcholine (SCh) or nicotine was reduced but not abolished, whereas the stimulation by acetylcholine (ACh) was abolished. It is concluded that SCh and nicotine act, at least in part, postsynaptically on the intrafusal muscle fibers whereas the action of ACh could be largely confined to the presynaptic endings on intrafusal fibers. However, some of these differences between the actions of ACh and of the other agents could be interpreted as due to variations in degree of direct antagonism of TC. © 1967 by The Williams & Wilkins Company