CHRONIC EXERCISE INCREASES SNAP-25 ABUNDANCE IN FAST-TRANSPORTED PROTEINS OF RAT MOTONEURONS

THE aim of the present study was to determine whether endurance exerci se training selectively modifies the relative abundance of some of the proteins that are subjected to fast axonal transport. Rats were train ed on treadmill for 11-13 weeks. [S-35]methionine was injected into th e ventral horn of L(4)-L(3) spinal cord segments, and transported [S-3 5]methionine-labelled proteins were analysed on fluorograms of sodium dodecyl sulphate polyacrylamide gels. The proportion of a 28 kDa prote in increased significantly after training, from 4.9% in controls to 7. 7% in trained animals. Two-dimensional electrophoresis and immunopreci pitation identified it as SNAP-25/SuP. The increased availability of S NAP-25, a synaptic protein, may constitute part of the molecular basis of exercise-induced changes in nerve terminal morphology and physiolo gy.