Exogenous testosterone treatment decreases diaphragm neuromuscular transmission failure in male rats

Cesar E. Blanco, Wen Zhi Zhan, Yun Hua Fang, Gary C. Sieck

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The effect of chronic exogenous testosterone (T) treatment on neuromuscular transmission in the diaphragm (Dia) muscle of adult male rats was determined. The contribution of neuromuscular transmission failure (NTF) to Dia fatigue was evaluated by superimposing intermittent direct muscle stimulation on repetitive nerve stimulation of isometric contraction in vitro. T treatment significantly reduced the contribution of NTF to Dia fatigue by ∼20% (P < 0.001). Fiber type-specific effects on NTF were determined by measuring Dia fiber glycogen levels subsequent to repetitive nerve or muscle stimulation. T treatment had no effect on glycogen depletion in Dia type I and IIa fibers regardless of stimulation route. In the control group, type IIx fibers demonstrated significantly less glycogen depletion after nerve stimulation compared with direct muscle stimulation (P < 0.05), suggesting the presence of NTF. In contrast, T treatment increased glycogen depletion of type IIx fibers during nerve stimulation to levels similar to those after direct muscle stimulation. These data indicate that testosterone treatment substantially improves neuromuscular transmission in the Dia.

Original languageEnglish (US)
Pages (from-to)850-856
Number of pages7
JournalJournal of applied physiology
Volume90
Issue number3
StatePublished - Mar 6 2001

Keywords

  • Anabolic-androgenic steroids
  • Contractile properties
  • Fatigue

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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