Simsek-Duran F, Ertunc M, Onur R. The effects of pentoxifylline on skeletal muscle contractility and neuromuscular transmission during hypoxia.
Indian J Pharmacol 2010;
41:213-7. [PMID:
20177491 PMCID:
PMC2812779 DOI:
10.4103/0253-7613.58509]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 12/20/2008] [Accepted: 10/22/2009] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES
The objective of this study was to investigate the effects of pentoxifylline (PTX), a drug that is mainly used for indications related to tissue hypoxia, on hypoxia-induced inhibition of skeletal muscle contractility and neuromuscular transmission in mice. We hypothesized that chronic PTX treatment alters skeletal muscle contractility and hypoxia-induced dysfunction.
MATERIALS AND METHODS
Mice were treated with 50 mg/kg PTX or saline intraperitoneally for a week. Following ether anesthesia, diaphragm muscles were removed; isometric muscle contractions and action potentials were recorded. Time to reach neuromuscular blockade and the rate of recovery of muscle contractility were assessed during hypoxia and re-oxygenation.
RESULTS
The PTX group displayed 90% greater twitch amplitudes (P < 0.01). Hypoxia depressed twitch contractions and caused neuromuscular blockade in both groups. However, neuromuscular blockade occurred earlier in PTX-treated animals (P < 0.05). Muscle contractures developed during hypoxia were more pronounced in the PTX group (P < 0.05). Re-oxygenation reduced contracture and indirect muscle contractions resumed. The rate of recovery of contractions was faster (P < 0.05) and the amplitude of contractions was greater (P < 0.01) in the PTX group. PTX treatment increased amplitude (P < 0.05) and shortened action potential (P < 0.05) without altering resting membrane potential, excitation threshold, and neurotransmitter release.
CONCLUSION
Chronic PTX treatment increases diaphragm contractility, but amplifies hypoxia-induced contractile dysfunction in mice. These results may implicate important clinical consequences for clinical usage of PTX in hypoxia-related conditions.
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