Effects of age and of chronic antidepressant treatment on [3H]tryptamine and [3H]dihydroalprenolol binding to rat cortical membranes.
1. The effects of age and of chronic antidepressant treatment on [3H]tryptamine and [3H]dihydroalprenolol binding site density were measured in brain cortical membranes from male Sprague-Dawley rats. 2. The density but not the affinity of [3H]tryptamine binding sites was increased in 18-month-old rats relative to 3-month-old rats. Neither the density nor the affinity of [3H]dihydroalprenolol binding sites was affected by age. 3. Chronic administration (28 days s.c. via Alzet osmotic minipumps) of tricyclic antidepressant drugs (daily doses: imipramine.HCl, 30 mg kg-1; desipramine.HCl, 10 mg kg-1; clomipramine.HCl, 10 mg kg-1) resulted in decreases in [3H]dihydroalprenolol binding site density but no changes in [3H]tryptamine binding site density; no changes in affinity of either site were observed. 4. Chronic administration (s.c. via Alzet osmotic minipumps) of monoamine oxidase inhibitor antidepressant drugs (daily doses: tranylcypromine.HCl, 0.5 and 1.0 mg kg-1; phenelzine sulfate, 5 and 10 mg kg-1, each for 28 days; clorgyline.HCl, 1.0 mg kg-1; (-)-deprenyl.HCl, 1.0 mg kg-1, each for 14 days) resulted in decreases in [3H]tryptamine binding site density, without any effects on the affinity of this site. In addition, each of these monoamine oxidase inhibitors except (-)-deprenyl resulted in a decrease in [3H]dihydroalprenolol binding site density. No affinity changes were observed. 5. These data indicate that the [3H]tryptamine binding site exhibits physiological changes with aging and is differentially sensitive to the actions of tricyclic antidepressants and monoamine oxidase inhibitor antidepressants, respectively.
Mousseau
D D
DD
Department of Psychiatry, University of Alberta, Edmonton, Canada.
McManus
D J
DJ
Baker
G B
GB
Juorio
A V
AV
Dewhurst
W G
WG
Greenshaw
A J
AJ
D000367:Age Factors; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism*; D004082:Dihydroalprenolol / Q000378:metabolism*; D008297:Male; D008995:Monoamine Oxidase / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000378:metabolism*; D014363:Tryptamines / Q000378:metabolism*
D000928:Antidepressive Agents; D011943:Receptors, Adrenergic, beta; D011985:Receptors, Serotonin; D014363:Tryptamines; C028413:dihydroalprenolol receptor; C030820:tryptamine; D004082:Dihydroalprenolol; D008995:Monoamine Oxidase