| RESEARCH PAPER
|Year : 1998 | Volume
| Issue : 6 | Page : 394-398
Selective alpha, adrenoceptor blockade produces antidepressant effect in mice
Kaur Gurpreet, SK Kulkarni
Objective: To investigate the antidepressant effect of selective alpha2-adrenoceptor blockade in mice.
Methods:The study was done in Laka mice employing forced swimming-induced despair behaviour as test model. They were acutely treated with dose of 0.25, 0.5, 1 and 2 mg/kg, SC and effect of 1 mg/kg of idazoxan was seen at different time intervals of 15,30, 60 and 120 min.The reversal of effect of idazoxan by reserpine (2 mglkg, ip), isoprenaline (8 mg/kg, ip) and clonidine (0.15 mglkg, ip) was also studied. The antidepressant effect of idazoxan (1 mgikg) was compared with imipramine (10 mg/kg, ip) and fluoxetine (10 mg/kg, ip) in acute study and with imipramine (10 mglkg, ip) in chronic study. Duration of immobility in seconds during the 6 min test session was recorded and used to assess the antidepressant effect.
Results: ldazoxan produced antidepressant effect in a dose dependent manner with maximum effect observed at 30 min. Prior administration of idazoxan (1 mg/kg) reversed isoprenaline- and clonidine-induced increase in immobility time. Further, the chronic idazoxan treatment (1 mg/kg x 9 d) reversed isoprenaline-induced despair behaviour but the effect was not statistically significant. Also the dose of 0.5 and 2 mgikg of idazoxan did not reverse clonidine (0.15 mg/kg) induced increased immobility time. ldazoxan also reversed reserpine (2 mg/kg) -induced despair behaviour after 4 h and 24 h. In acute study, idazoxan (1 mg/kg) produced significant and better effect as compared to imipramine and fluoxetine. The chronic effect of idazoxan was also more pronounced than chronic imipramine treatment.
Conclusion: The results of the present study indicate involvement of presynaptic alpha2-adrenoceptors in the antidepressant effect of idazoxan.
Source of Support: None, Conflict of Interest: None