Alterations in pharmacological responses of rabbit skeletal muscle by reserpine pretreatment

In the present study the isolated phrenic nerve-diaphragm preparation from rabbits pretreated with reserpine was used. Isometric twitch tension response was recorded. Concentration-response curves which demonstrated the neuromuscular blocking activity of d-tubocurarine were constructed. Curarized diaphragms were directly stimulated and concentration-response curves were made which demonstrated caffeine's ability to potentiate twitch tension. Pretreatment of rabbits with reserpine resulted in a potentiation of the effects of d-tubocurarine and caffeine. The present data indicate that pretreatment of rabbits with reserpine resulted in alteration of the in vitro responses of skeletal muscle to d-tubocurarine and caffeine.