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 115
- Downloads 0
Effects of taurine on contractions of the porcine coronary artery.
The actions and mechanisms of taurine on vascular contractions have been studied in the isolated porcine coronary artery. Taurine depressed histamine-, serotonin-, KCl- and CaCl(2)-induced contractions in a concentration...
Novel variant of CYP2D6*6 is undetected by a commonly used genotyping procedure.
We report the identification of a novel and defective variant of the gene encoding cytochrome P450 2D6 (CYP2D6). This novel variant is a subtype of CYP2D6*6 that was undetected by a commercially available 5' exonuclease-...
Efficacy of bretazenil against cortical epileptic afterdischarges increases during early ontogeny in rats.
The effect of a benzodiazepine partial agonist bretazenil on cortical epileptica fterdischarges was studied in 12-, 18- or 25-day-old rat pups with implanted electrodes. Afterdischarges were induced by low-frequency stim...
Effect of lipopolysaccharide and antidepressant drugs on glucocorticoid receptor-mediated gene transcription.
It has been hypothesized that pro-inflammatory response and hyperactivity of hypothalamic-pituitary-adrenocortical axis (HPA) are involved in the pathogenesis of depression. Hyperactivity of HPAaxis results probably from...
Hypertriglyceridemia but not hypercholesterolemia induces endothelial dysfunction in the rat.
In humans, hypercholesterolemia and hypertriglyceridemia induce endothelial dysfunction and therefore lead to atherosclerosis. In contrast, rats are resistant to atherosclerosis. Here we analyze whether rats respond to h...