Fatigue of isolated rat diaphragm: Role of impaired neuromuscular transmission

T. K. Aldrich, A. Shander, I. Chaudhry, H. Nagashima

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

We compared the contributions of impaired neuromuscular transmission (transmission fatigue) and impaired muscle contractility (contractile fatigue) to fatigue of the isolated rat diaphragm. To make this comparison, we measured the differences in active tension elicited by direct muscle stimulation and by indirect (phrenic nerve) stimulation before and after fatigue induced by indirect supramaximal stimulation at varying frequencies and durations. Transmission fatigue was observed after all experimental protocols. Although significant contractile fatigue was not demonstrated after brief periods of low-frequency stimulation (6 min, 15 Hz, 25% duty cycle), it was present after longer or higher frequency stimulation. We repeated the direct stimulation in the presence of neuromuscular blockade with 6 μM d-tubocurarine to demonstrate that a reduced response to stimulation of intramuscular branches of the phrenic nerve during direct stimulation was not responsible for the apparent contractile fatigue. Since we found significant decreases in the response to direct stimulation even after neuromuscular blockade, we could verify the presence of contractile fatigue. We conclude that both contractile and transmission fatigue can occur in the isolated rat diaphragm and that transmission fatigue is a much more important factor after brief periods of fatiguing contractions.

Original languageEnglish (US)
Pages (from-to)1077-1083
Number of pages7
JournalJournal of Applied Physiology
Volume61
Issue number3
StatePublished - 1986

Fingerprint

Diaphragm
Fatigue
Phrenic Nerve
Neuromuscular Blockade
Tubocurarine
Muscle Fatigue
Muscles

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Aldrich, T. K., Shander, A., Chaudhry, I., & Nagashima, H. (1986). Fatigue of isolated rat diaphragm: Role of impaired neuromuscular transmission. Journal of Applied Physiology, 61(3), 1077-1083.

Fatigue of isolated rat diaphragm : Role of impaired neuromuscular transmission. / Aldrich, T. K.; Shander, A.; Chaudhry, I.; Nagashima, H.

In: Journal of Applied Physiology, Vol. 61, No. 3, 1986, p. 1077-1083.

Research output: Contribution to journalArticle

Aldrich, TK, Shander, A, Chaudhry, I & Nagashima, H 1986, 'Fatigue of isolated rat diaphragm: Role of impaired neuromuscular transmission', Journal of Applied Physiology, vol. 61, no. 3, pp. 1077-1083.
Aldrich TK, Shander A, Chaudhry I, Nagashima H. Fatigue of isolated rat diaphragm: Role of impaired neuromuscular transmission. Journal of Applied Physiology. 1986;61(3):1077-1083.
Aldrich, T. K. ; Shander, A. ; Chaudhry, I. ; Nagashima, H. / Fatigue of isolated rat diaphragm : Role of impaired neuromuscular transmission. In: Journal of Applied Physiology. 1986 ; Vol. 61, No. 3. pp. 1077-1083.
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