β2-Agonist administration increases sarcoplasmic reticulum Ca2+-ATPase activity in aged rat skeletal muscle

Aging is associated with a slowing of skeletal muscle contractile properties, including a decreased rate of relaxation. In rats, the age-related decrease in the maximal rate of relaxation is reversed after 4-wk administration with the beta2-adrenoceptor agonist (beta2-agonist) fenoterol. Given the critical role of the sarcoplasmic reticulum (SR) in regulating intracellular Ca2+ transients and ultimately the time course of muscle contraction and …