Rapid reduction in parvalbumin concentration during chronic stimulation of rabbit fast twitch muscle.

Chronic indirect stimulation of fast twitch rabbit muscle induced a rapid reduction in parvalbumin concentration. When compared to the unstimulated contralateral muscle, parvalbumins were reduced to 55% following 6 days of stimulation. Prolonged stimulation further reduced parvalbumins so that they were undetectable after 28 days. The time course of these changes appears to be related with the previously observed changes in the sarcoplasmic reticulum.