The effect of imipramine treatment on brain serotonin receptors and beta-adrenoceptors and on pineal beta-adrenergic function in adult and aged rats.
The effect of age and of imipramine treatment on cortical serotonin and beta-adrenergic binding sites and on pineal N-acetylserotonin and melatonin were examined in Fischer-344 rats. Cortical serotonin-1 and -2 receptor binding was reduced by 15 and 22.5% respectively, in 24 vs. 6 months old animals. Ten single daily imipramine (10 mg/kg) injections in the aged animals resulted in reductions in both types of serotonin sites, while in adult animals significant binding reduction occurred only at the 5HT2 site. Cortical beta-adrenoceptor binding was also diminished in the aged rats. Imipramine treatment elicited a significantly greater decrease in these adrenergic sites in the aged (39.2%) than in the adult (27.6%) animals. In the pineal gland, N-acetylserotonin and melatonin content were reduced by age; imipramine treatment induced decreases in both indoles in the adult animals and a reduction in N-acetylserotonin in the aged animals. These age-related effects of imipramine on cortical serotonin receptor and beta-adrenoceptor binding and on pineal indoles may be a consequence of the higher drug and metabolite (desmethylimipramine) blood and tissue concentrations which were found in the aged animals.
D000375:Aging; D000818:Animals; D001921:Brain / Q000378:metabolism / Q000502:physiology*; D003891:Desipramine / Q000378:metabolism; D004082:Dihydroalprenolol; D007099:Imipramine / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D007211:Indoles / Q000378:metabolism; D008297:Male; D010870:Pineal Gland / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000502:physiology; D011985:Receptors, Serotonin / Q000187:drug effects*
D007211:Indoles; D011943:Receptors, Adrenergic, beta; D011985:Receptors, Serotonin; D004082:Dihydroalprenolol; D007099:Imipramine; D003891:Desipramine