31P-NMR study on effects of electric shock on swimming leeches, Hirudo medicinalis

1. We evaluated the effect of electric shock on swimming leeches by measuring changes in high-energy phosphate metabolism using in vivo 31P-NMR. 2. Leeches electrically stimulated during swimming showed anodal galvanotaxis and stopped swimming with stimulation at strong current. 3. Comparison of the concentrations of high-energy phosphate metabolites before and after electric shock using 31P-NMR revealed a marked decrease in beta-ATP and an increase in that of Pi. 4. Electric shock apparently induces excessive muscle fatigue in leeches, resulting in transient paralysis.