Effects of blockade of central dopamine D1 and D2 receptors on thermoregulation, metabolic rate and running performance.
Journal Title: Pharmacological Reports - Year 2010, Vol 62, Issue 1
Abstract
To assess the effects of a blockade of central D1- and D2-dopaminergic receptors on metabolic rate, heat balance and running performance, 10 nmol (2 microl) of a solution of the D(1) antagonist SCH-23390 hydrochloride (SCH, n = 6), D2 antagonist eticlopride hydrochloride (Eti, n = 6), or 2 microl of 0.15 M NaCl (SAL, n = 6) was injected intracerebroventricularly into Wistar rats before the animals began graded running until fatigue (starting at 10 m/min, increasing by 1 m/min increment every 3 min until fatigue, 5% inclination). Oxygen consumption and body temperature were recorded at rest, during exercise and following 30 min of recovery. Control experiments with injection of two doses (10 and 20 nmol/rat) of either SCH or Eti solution were carried out in resting rats as well. Body heating rate, heat storage, workload and mechanical efficiency were calculated. Although SCH and Eti treatments did not induce thermal effects in resting animals, they markedly reduced running performance (-83%, SCH; -59% Eti, p < 0.05) and decreased maximal oxygen uptake (-79%, SCH; -45%, Eti, p < 0.05) in running rats. In addition, these treatments induced a higher body heating rate and persistent hyperthermia during the recovery period. Our data demonstrate that the alteration in dopamine transmission induced by the central blockade of dopamine- D1 and D2 receptors impairs running performance by decreasing the tolerance to heat storage. This blockade also impairs the dissipation of exercise-induced heat and metabolic rate recovery during the post-exercise period. Our results provide evidence that central activation of either dopamine- D1 or D2 receptors is essential for heat balance and exercise performance.
Authors and Affiliations
Cláudio Balthazar, Laura Leite, Roberta Ribeiro, Danusa Soares, Cândido Coimbra
Keywords
Related Articles
- EP ID EP83512
- DOI -
- Views 109
- Downloads 0
Potential neurotoxic effect of ethylene glycol ethers mixtures.
Background: Ethylene glycol ethers (EGEs) are widely used as mixtures in various industrial processes and in many household products. 2-Methoxyethanol and 2-ethoxyethanol primarily exert gonadotoxic effect, while 2-butox...
Modulation of in vivo immunoglobulin production by endogenous histamine and H1R and H2R agonists and antagonists.
The present study was designed to delineate the immunomodulatory role of histamine receptors (H1R and H2R) and their antibody generation in a rabbit model. Six groups containing 18 rabbits each received either vehicle (s...
Effects of high-fat mixed-lipid diet and exercise on the antioxidant system in skeletal and cardiac muscles of rats with colon carcinoma.
Epidemiological and experimental studies suggest that eating habits and a sedentary lifestyle play a critical role in the incidence of colon carcinoma. In order to investigate the effects of high-fat mixed-lipid (HFML) d...
Possible mechanism by which zinc protects the testicular function of rats exposed to cigarette smoke.
The aim of this study was to evaluate the changes in testicular function of rats due to cigarette smoke exposure and the possible mechanism by which zinc protects against these alterations.
Effect of antidepressant drugs on cytochrome P450 2C11 (CYP2C11) in rat liver.
Background: Rat CYP2C11 (besides CYP2C6) can be regarded as a functional counterpart of human CYP2C9. The aim of the present study was to investigate the influence of classic and novel antidepressant drugs on the activit...