Breakdown and formation of high-energy phosphates and octopine in the adductor muscle of the scallop,Chlamys opercularis (L.), during escape swimming and recovery

Abstract

1. The scallopChlamys opercularis uses jet propulsion swimming as a means of escape if attacked by the star fishMarthasterias glacialis. The energy for these rapid movements is supplied by the depletion of the phosphagen phospho-L-arginine. During escape swimming the energy charge of the adductor muscle drops from 0.93 to 0.42. Due to the decrease of phospho-L-arginine from 20.4 to 1.5 μmol/g fresh wt there is a concomitant increase of L-arginine from 14.7 to 34.7 μmol/g fresh wt. No octopine, D- or L-lactate was accumulated in exhausted animals. 2. During the first 30 min of recovery in aerated sea water, octopine, instead of lactate, is synthesized in adductor muscles. The energy charge rises to 0.92. Within 60 min the phospho-L-arginine pool is replenished and half of the accumulated octopine again metabolized. 3. During anaerobic revovery, i.e. when the scallops are kept exposed to air, octopine synthesis is pronounced (7.5 μmol/g fresh wt/h). The energy charge increases to 0.85. However, under these conditions no phospho-L-arginine is formed. 4. There is no evidence for transport of octopine from the adductor muscle to other tissues.