抄録
Denervation itself produces a striking alteration in the surface membrane of muscle fiber in which the region of acetvicholine sensitivity spreads out from the endplates to the whole of the fiber membrane in the rat (1, 2) and in the frog (3). In addition, changes in the characteristics of the sarcoplasmic reticulum may be considered as a possible mechanism for the occurrence of the supersensitivity in the denervated muscle: preservation and proliferation of the sarcoplasmic reticulum demonstrated by electron microscopy (4), the rise in susceptibility to caffeine that appears to exert direct action on the sarcoplasmic reticulum (5) and the marked increase in calcium uptake by the isolated sarcoplasmic reticulum (6, 7).
More recently the marked increase in contractures induced by drugs replacing calcium ions by strontium ions was also reported by Taga, Takayanagi and Takagi (8).
The aim in this paper was to study non-specific potentiation (non-specific supersensitivity) with views of the contractile activity and the potentiation of drug-contracttires in substituting strontium ions for calcium ions in the denervated muscle. For this purpose changes in function of the sarcoplasmic reticulum after denervation were further investigated.
