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The giant miniature endplate potentials frequency is increased in aged rats
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Orientador(es)
Resumo(s)
At the neuromuscular junction, spontaneous giant events (GMEPPs) are enhanced in different conditions when degenerative and/or remodeling processes take place, but no one investigated their incidence upon aging. In the present work, we evaluated evoked and spontaneous neuromuscular transmission events recorded from single muscle fibers. Phrenic-diaphragm preparations of 3-4, 12-16, 36-40 and 70-80 weeks old rat males were used. We found that the occurrence of GMEPPs significantly increases in aged rats. Moreover, in old rats the neuromuscular transmission was significantly impaired due to a significant decrease in the amplitude and quantal content of evoked endplate potentials. Interestingly, the number of observed EPPs failures were ∼ 3 times lower than the predicted value based on the quantal content. This discrepancy was not observed in infant or adult rats. The coincidence of a high GMEPPs frequency with a lower than expected EPPs failure rate suggests that GMEPPs events are needed to preserve effective neuromuscular transmission in aged animals.
Descrição
© 2014 Elsevier Ireland Ltd. All rights reserved.
Palavras-chave
Aging GMEPPs Neuromuscular junction Neuromuscular transmission
Contexto Educativo
Citação
Neurosci Lett. 2015 Jan 1;584:224-229
Editora
Elsevier