Chronic imipramine treatment upregulates IR2-imidazoline receptive sites in rat brain.
A low density of brain IR2-imidazoline receptive sites has previously been linked to depression. In this study we evaluated brain IR2-binding sites in a rat model of depression, olfactory bulbectomy, and determined the effects of chronic imipramine treatment in vivo on these sites. Compared with sham-operated controls, adaptation to olfactory bulbectomy had no effect on either the density (Bmax) or affinity (KD) of [3H]-idazoxan binding to brain IR2 sites. However, 25 days of imipramine treatment (i.p., 20 mg/kg/day) enhanced significantly the density of IR2 binding sites, with no change in affinity in both the model and the control group. These results indicate that the brain IR2-imidazoline receptive sites might be a target for antidepressants.
Zhu
H
H
Department of Psychiatry, University of Mississippi Medical Center, Jackson 39216-4505, USA.
Paul
I A
IA
McNamara
M
M
Redmond
A
A
Nowak
G
G
Piletz
J E
JE
D000818:Animals; D000928:Antidepressive Agents; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003863:Depression / Q000378:metabolism; D019329:Idazoxan / Q000378:metabolism; D054755:Imidazoline Receptors; D007099:Imipramine / Q000494:pharmacology*; D008297:Male; D009830:Olfactory Bulb / Q000502:physiology / Q000601:surgery; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000187:drug effects* / Q000378:metabolism*; D014316:Tritium; D015854:Up-Regulation
D000928:Antidepressive Agents; D054755:Imidazoline Receptors; D011955:Receptors, Drug; D014316:Tritium; D007099:Imipramine; D019329:Idazoxan