Hippocampal mossy fiber sprouting induced by forced and voluntary physical exercise.
Alterations in the function and organization of synapses have been proposed to induce learning and memory. Previous studies have demonstrated that mossy fiber induced by overtraining in a spatial learning task can be related with spatial long-term memory formation. In this work we analyzed whether physical exercise could induce mossy fiber sprouting by using a zinc-detecting histologic technique (Timm). Rats were submitted to 3 and 5days of forced or voluntary exercise. Rat brains were processed for Timm's staining to analyze mossy fiber projection at 7, 12 and 30days after the last physical exercise session. A significant increase of mossy fiber terminals in the CA3 stratum oriens region was observed after 5days of forced or voluntary exercise. Interestingly, the pattern of Timm's staining in CA3 mossy fibers was significantly altered when analyzed 12days after exercise but not at 7days post-exercise. In contrast, animals trained for only 3days did not show increments of mossy fiber terminals in the stratum oriens. Altogether, these results demonstrate that sustained or programmed exercise can alter mossy fiber sprouting. Further Investigations are necessary to determine whether mossy fiber sprouting induced by exercise is also involved in learning and memory processes.
Departamento de Fisiologia, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu 862, Ed. Ciências Biomédicas, 5 degrees andar. Vila Clementino, 04023-900, São Paulo (SP), Brazil.
Michelle
M
Toscano-Silva
Sérgio
S
Gomes da Silva
Fulvio Alexandre
FA
Scorza
Jean Jacques
JJ
Bonvent
Esper Abrão
EA
Cavalheiro
Ricardo Mario
RM
Arida
D000818:Animals; D006624:Hippocampus / Q000033:anatomy & histology*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D019599:Mossy Fibers, Hippocampal / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013194:Staining and Labeling / Q000379:methods; D013997:Time Factors
D019344:Lactic Acid