M. Papp et al., EFFECTS OF IMIPRAMINE ON SEROTONERGIC AND BETA-ADRENERGIC-RECEPTOR BINDING IN A REALISTIC ANIMAL-MODEL OF DEPRESSION, Psychopharmacology, 114(2), 1994, pp. 309-314
Chronic exposure to mild unpredictable stress (CMS) has previously bee
n found to cause an antidepressant-reversible decrease in the consumpt
ion of palatable sweet solutions. In the present study, in addition to
confirming these behavioural observations, the binding properties of
cortical beta-adrenergic and 5HT(2) receptors, and hippocampal 5HT(1A)
receptors were studied (using the ligands [H-3]-dihydroalprenolol, [H
-3]-ketanserin and [H-3]-8-OH-DPAT, respectively), following 7 weeks o
f CMS and 4 weeks of imipramine treatment (10 mg/kg per day). CMS incr
eased B-max for all three receptor systems. Impramine decreased B-max,
reversing the effect of CMS, for beta-adrenergic and 5HT(2) receptor
binding, but increased B-max for 5HT(1A) receptor binding. K(D)s were
unaffected by either treatment. The beta-receptor and 5HT(2) receptor
binding data are consistent with accounts of antidepressant action der
ived from studies in normal animals, but the 5HT(1A) receptor binding
data are more difficult to reconcile. In no case was there a good corr
elation between receptor binding and behavioural data.