[Effect of tranquilizer doping on the muscular activity on the sport horse. I. -- Acepromazine (author's transl)].

Doping with tranquilizers has appeared recently in horse-back riding sports. In this paper we study the effects of acepromazine, one of the main tranquilizers used, on various physiological and biochemical aspects of muscular activity (cardiac and respiratory rhythms, seric rates of glucose, urea, protein, creatine phosphokinase, glutamate oxalacetate transaminase, alkaline phosphatase). A low dose (0.02 mg/kg) of acepromazine is injected; the evolution of the variables is studied before and after a standardized effort. After the effort and during recuperation, acepromazine administration causes: -- a decrease of respiratory rhythm and seric protein rats, -- an increase of creatine phosphokinase rate. A discussion of these results suggests that acepromazine depresses the respiratory centers and has a possible toxic effect on the muscle cell.