Time course of tension decay after stretch and unloaded shortening velocity in molluscan catch muscle at various physiological states

Abstract

1. 1. The anterior byssus retractor muscle of Mytilus was stimulated to contract with ACh, and the time courses of tension decay after an applied stretch (6% of l 0), as well as the unloaded shortening velocity, were examined at various states, i.e. (1) at the peak of initial tension development, (2) during the prolonged application of ACh, (3) after washout of ACh, (4) in the sucrose-hypertonic solution and (5) in the NaCl-hypertonic solution. 2. 2. The tension decay after stretch was resolved into three exponential components. 3. 3. The relationship between the amplitudes of three exponential components and the unloaded shortening velocity was examined in the above five states. It was shown that the intermediate component and the slow one were related to active and tonic contractions, respectively.