EFFECTS OF SOME DIVALENT CATIONS ON THE DENERVATED SKELETAL MUSCLE OF THE RAT

Abstract

There have been few studies on actions of divalent cations on mammalian skeletal muscles (1) as compared to amphibian muscles, which have been used in the study of the role of calcium in the excitation-contraction coupling process (2, 3). Related studies on mammalian denervated skeletal muscle are also few.
Denervated skeletal muscles were generally reported to be more sensitive to acetylcholine (ACh) (4, 5), but Kiku-iri (6) indicated that twitch and tetanus evoked by direct electrical stimulation were reduced gradually with the lapse of time after denervation in the sartorius muscle of the frog, while the pattern of caffeine-contracture in the denervated muscle was not different from that in the innervated muscle. Gutmann and Sandow (7) reported that a decrease in twitch and tetanus tensions became progressivly greater with increased duration of denervation in the extensor digitorum longus muscle of rats, whereas the denervated muscle became more sensitive to caffeine.
The aim of the present study was to investigate effects of some divalent cations, electrical stimulation and substituting strontium ions for calcium ions in the bath solution on the rat denervated skeletal muscle.