Effect of the beta-agonist clenbuterol on dexamethasone-induced diaphragm dysfunction in rabbits

American Journal of Respiratory and Critical Care Medicine
T X JiangP G Wilcox

Abstract

The present study was designed to examine whether clenbuterol (CLEN) could reduce dexamethasone (DEX)-induced diaphragm dysfunction. We studied four groups of New Zealand white (NZW) rabbits, each receiving one of the following daily injections subcutaneously for 2 wk: saline (control), DEX 3 mg/kg, DEX 3 mg/kg + CLEN 2 mg/kg, and CLEN 2 mg/kg. Diaphragm fiber cross-sectional areas (CSA) were measured. Twitch transdiaphragmatic pressure (Pdi) and tetanic Pdi were measured during bilateral phrenic stimulation both before and after 60 min of inspiratory resistive loading (IRL). DEX produced a marked atrophy of type IIa and type IIb diaphragm fibers. This diaphragm atrophy was prevented by CLEN in the DEX plus CLEN group. CLEN alone increased CSAs of all three types of diaphragm fibers. Significant reductions in twitch Pdi and tetanic Pdi at all stimulation frequencies both before and after IRL were observed similarly in the DEX group as well as in the DEX plus CLEN group compared with the control animals. We conclude that DEX produces significant diaphragm atrophy and decreases diaphragmatic contractility. CLEN produces hypertrophy of the diaphragm and minimizes diaphragm atrophy induced by DEX, but it has no demonstrable protect...Continue Reading

Citations

Jan 28, 1998·American Journal of Respiratory and Critical Care Medicine·T X JiangJ D Road
Mar 28, 1998·American Journal of Respiratory and Critical Care Medicine·T X JiangJ D Road
Apr 28, 2004·Experimental Physiology·Maria Antonietta PellegrinoCarlo Reggiani
Jun 29, 2013·The International Journal of Biochemistry & Cell Biology·O SchakmanJ P Thissen
Jul 9, 1998·Journal of Applied Physiology·H F Van Der HeijdenC L Van Herwaarden
Sep 18, 1997·Journal of Applied Physiology·J D Road, A M Cairns
Apr 12, 2003·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Mario FournierMichael I Lewis

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