Document Detail

Clenbuterol administration does not attenuate the exercise-induced pulmonary arterial, capillary or venous hypertension in strenuously exercising Thoroughbred horses.
MedLine Citation:
PMID:  11093630     Owner:  NLM     Status:  MEDLINE    
The present study was carried out to ascertain whether beta2-adrenergic receptor stimulation with clenbuterol would attenuate the pulmonary arterial, capillary and venous hypertension in horses performing high-intensity exercise and, in turn, modify the occurrence of exercise-induced pulmonary haemorrhage (EIPH). Experiments were carried out on 6 healthy, sound, exercise-trained Thoroughbred horses. All horses were studied in the control (no medications) and the clenbuterol (0.8 pg/kg bwt, i.v.) treatments. The sequence of these treatments was randomised for every horse, and 7 days were allowed between them. Using catheter-tip-transducers whose in-vivo signals were referenced at the point of the left shoulder, right heart/pulmonary vascular pressures were determined at rest, sub-maximal exercise and during galloping at 14.2 m/s on a 3.5% uphill grade--a workload that elicited maximal heart rate and induced EIPH in all horses. In the control experiments, incremental exercise resulted in progressive significant increments in right atrial as well as pulmonary arterial, capillary and venous (wedge) pressures and all horses experienced EIPH. Clenbuterol administration to standing horses caused tachycardia, but significant changes in mean right atrial or pulmonary vascular pressures were not observed. During exercise performed after clenbuterol administration, heart rate as well as right atrial and pulmonary arterial, capillary and wedge pressures also increased progressively with increasing work intensity. However, these values were not found to be statistically significantly different from corresponding data in the control study and the incidence of EIPH remained unaffected. Since clenbuterol administration also does not affect the transpulmonary pressure during exercise, it is unlikely that the transmural force exerted onto the blood-gas barrier of exercising horses is altered following i.v. clenbuterol administration at the recommended dosage.
M Manohar; T E Goetz; P Rothenbaum; S Humphrey
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Equine veterinary journal     Volume:  32     ISSN:  0425-1644     ISO Abbreviation:  Equine Vet. J.     Publication Date:  2000 Nov 
Date Detail:
Created Date:  2001-01-02     Completed Date:  2001-01-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0173320     Medline TA:  Equine Vet J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  546-50     Citation Subset:  IM    
Department of Veterinary Biosciences and Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana 61802, USA.
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MeSH Terms
Adrenergic beta-Agonists / administration & dosage,  therapeutic use*
Clenbuterol / administration & dosage,  therapeutic use*
Hemorrhage / etiology,  prevention & control,  veterinary
Horse Diseases / drug therapy*
Hypertension / drug therapy,  etiology,  veterinary*
Hypertension, Pulmonary / drug therapy,  etiology,  veterinary*
Physical Conditioning, Animal / adverse effects*
Pulmonary Circulation / drug effects
Reg. No./Substance:
0/Adrenergic beta-Agonists; 37148-27-9/Clenbuterol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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