[Calcium transport and ATPase activity of sarcoplasmic reticulum in normal and denervated rabbit muscles]

The properties of sarcomplasmic reticulum Ca-pump from normal and denervated rabbit muscles were investigated. Ca+2 ion transport in denervated muscle reticulum was subject to Michaelis-Menten kinetics. The rate of fast Ca2+ outflux from the vesicles was enhanced after denervation; this caused a decrease in the transport efficiency and an increase of the "basic" ATP-ase. At the same time the rate of Ca2+ accumulation and the Ca-ATP-ase transport activity were enhances by a factor of 1.5. Kinetic properties of the denervated sarcoplasmic reticulum proved to be closely related to the features of the excitation-contraction cycle in these muscles.