title: Effects of cocaine on plasma catecholamine and muscle glycogen concentrations during exercise in the rat.
abstract: This study was designed to test the hypothesis that cocaine (C) alters the normal physiological responses to exercise. Male rats were injected with saline (S) or C (12.5 mg/kg) either intravenously (iv) or intraperitoneally (ip). After injection the animals were allowed to rest for 30 min or were run on the treadmill (26 m/min, 10% grade). At rest plasma epinephrine values were 245 +/- 24 pg/ml in the S group and 411 +/- 43 (ip) and 612 +/- 41 (iv) pg/ml in the C groups (P less than 0.05 between S and C). During exercise plasma epinephrine levels were 615 +/- 32 pg/ml in S and 1,316 +/- 58 (ip) and 1,208 +/- 37 (iv) pg/ml in the C groups (P less than 0.05 between S and C). Similar results were obtained for norepinephrine. Glycogen content in the white vastus lateralis muscle was reduced to 31 +/- 2 mumol/g in S after exercise, but after C and exercise the values were 12 +/- 4 (ip) and 16 +/- 3 (iv) mumol/g (P less than 0.05 between S and C). There was no effect of the drug on this parameter at rest. Blood lactate rose to 4.8 +/- 1.0 (ip) and 5.8 +/- 1.3 (iv) mM in the C groups but to only 3.0 +/- 0.2 in the S group after exercise (P less than 0.05 between S and C). These results show that C and exercise combined exert a more dramatic effect on plasma catecholamine, muscle glycogen, and blood lactate concentrations than do C and exercise alone. They provide further insight into explaining the adverse effects of C on exercise endurance observed previously (Bracken et al., J. Appl. Physiol. 66: 377-383, 1989).
authors.affiliation: Exercise Biochemistry Laboratory, Brigham Young University, Provo, Utah 84602.
authors.forename: R K
authors.initials: RK
authors.lastname: Conlee
authors.forename: D W
authors.initials: DW
authors.lastname: Barnett
authors.forename: K P
authors.initials: KP
authors.lastname: Kelly
authors.forename: D H
authors.initials: DH
authors.lastname: Han
mesh_terms: D000818:Animals; D002395:Catecholamines / Q000097:blood*; D003042:Cocaine / Q000633:toxicity*; D004298:Dopamine / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006003:Glycogen / Q000378:metabolism; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D009132:Muscles / Q000187:drug effects* / Q000378:metabolism; D009638:Norepinephrine / Q000097:blood; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology; D005082:Physical Exertion / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002395:Catecholamines; D005230:Fatty Acids, Nonesterified; D007773:Lactates; D019344:Lactic Acid; D006003:Glycogen; D003042:Cocaine; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine