Imidazoline receptor antagonists idazoxan and efaroxan enhance locomotor functions in rats.

UNLABELLED Discovered in 1984, imidazoline receptors (I1, I2, I3) are located centrally and peripherally being involved in various physiologic and pathophysiologic processes in the body. Experimental and clinical investigations have suggested the interrelations between imidazoline, adrenergic, dopaminergic, glutamatergic and opioid systems, which may explain the influence of different substances acting on imidazoline receptors in cognitive disorders, behavioral disturbances and motor diseases pathways. AIM To investigate the effects of two imidazoline receptor antagonists on locomotor activity and endurance capacity in rats. MATERIAL AND METHODS The experiment was carried out with white male Wistar rats (200-250 g) divided into 3 groups of 7 animals each, treated intraperitonealy with the same volume of solution as follows: Group I (Control): distilled water 0.3 ml/100 g body weight; Group II (IDZ): idazoxan 3 mg/kbw; Group III (EFR): efaroxan 1 mg/kbw. Exercise capacity was evaluated using a locomotor PanLAB treadmill test. The data were presented as mean +/- standard deviation and significance was tested by SPSS Statistics for Windows version 17.0 and ANOVA method. Experimental protocol was implemented according to recommendations of the Gr.T. Popa" University Committee for Research and Ethical Issues. RESULTS Intraperitoneal administration of idazoxan and efarox- an resulted in a significant increase in running distance compared with the control group (p < 0.05). At the same time a reduction in the number and time of electric shocks delivered to motivate the animal to keep running was observed. In this experimental behavioral model the effects of idazoxan on the evaluated parameters were more intense than those of efaroxan. CONCLUSIONS In our experimental conditions we demonstrated the ability of imidazoline receptor antagonists idazoxan and efaroxan to improve fatigue resistance during forced running in rats.