The effect of nerve stump length on cholinesterase activity was examined in denervated rat diaphragm. Nerve stump length had a substantial effect on end-plate cholinesterase but no effect on background cholinesterase. The denervation-induced decrease in end-plate cholinesterase occurred earlier in muscle having a short stump. End-plate cholinesterase in muscle with a short stump was significantly less than in muscle with a long stump 15 to 48 h after denervation. This difference vanished by 72 h. Control experiments indicate that the substantial effect of stump length on end-plate cholinesterase cannot be attributed to a more rapid loss of the small amount of nerve-associated cholinesterase in the shorter nerve stump. The results of these experiments support the concept that the influence of nerve on background cholinesterase is mediated primarily by the activity generated in muscle by nerve, whereas the influence on end-plate cholinesterase is mediated by an activity-independent mechanism.
ASJC Scopus subject areas
- Developmental Neuroscience