Preferential reduction of binding of sup 125 I-iodopindolol to beta-1 adrenoceptors in the amygdala of rat after antidepressant treatments
- Veterans Affairs Medical Center, Philadelphia, PA (USA)
This study utilized quantitative receptor autoradiography to examine the effects of repeated administration of antidepressants to rats on the binding of the beta adrenoceptor antagonist, {sup 125}I-iodopindolol ({sup 125}I-IPIN) to either beta-1 or beta-2 adrenoceptors in various regions of brain. Antidepressants were selected to represent various chemical and pharmacological classes including tricyclic compounds (desipramine and protriptyline), monoamine oxidase inhibitors (clorgyline, phenelzine and tranylcypromine), atypical antidepressants (mianserin and trazodone) and selective inhibitors of the uptake of serotonin (citalopram and sertraline). Additionally, rats were treated with various psychotropic drugs that lack antidepressant efficacy (cocaine, deprenyl, diazepam and haloperidol). Repeated treatment of rats with desipramine, protriptyline, clorgyline, phenelzine, tranylcypromine or mianserin reduced the binding of {sup 125}I-IPIN to beta-1 adrenoceptors in many brain areas. Only in the basolateral and lateral nuclei of the amygdala did all six of these antidepressants significantly reduce {sup 125}I-IPIN binding to beta-1 adrenoceptors. In these amygdaloid nuclei, the magnitude of the reduction in the binding of {sup 125}I-IPIN caused by each of these drugs was comparable to or greater than the reduction in binding produced in any other region of brain. Reductions of binding of {sup 125}I-IPIN after antidepressant treatments were not consistently observed in the cortex, the area of brain examined most often in homogenate binding studies. Only the monoamine oxidase inhibitors caused reductions in the binding of {sup 125}I-IPIN to beta-2 adrenoceptors, and this effect was generally localized to the amygdala and hypothalamus.
- OSTI ID:
- 5733424
- Journal Information:
- Journal of Pharmacology and Experimental Therapeutics; (USA), Journal Name: Journal of Pharmacology and Experimental Therapeutics; (USA) Vol. 257:2; ISSN JPETA; ISSN 0022-3565
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ANIMALS
ANTIDEPRESSANTS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BODY
BRAIN
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM AGENTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYME INHIBITORS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
PSYCHOTROPIC DRUGS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SYMPATHOMIMETICS
VASODILATORS
VERTEBRATES