Chronic exercise increases SNAP-25 abundance in fast-transported proteins of rat motoneurones.

The aim of the present study was to determine whether endurance exercise training selectively modifies the relative abundance of some of the proteins that are subjected to fast axonal transport. Rats were trained on treadmill for 11-13 weeks. [35S]methionine was injected into the ventral horn of L4-L5 spinal cord segments, and transported [35S]methionine-labelled proteins were analysed on fluorograms of sodium dodecyl sulphate polyacrylamide gels. The proportion of a 28 kDa protein increased significantly after training, from 4.9% in controls of 7.7% in trained animals. Two-dimensional electrophoresis and immunoprecipitation identified it as SNAP-25/SuP. The increased availability of SNAP-25, a synaptic protein, may constitute part of the molecular basis of exercise-induced changes in nerve terminal morphology and physiology.