title: Up-regulation of beta 1-adrenergic receptors in rat brain after chronic citalopram and fluoxetine treatments.
abstract: Quantitative receptor autoradiography was used to study the effects of the selective serotonin reuptake inhibitors citalopram and fluoxetine and the tricyclic antidepressant imipramine on the regulation of beta 1-adrenergic receptors in the rat brain. Rats were treated with saline, citalopram (10 mg kg-1), fluoxetine (10 mg kg-1), or imipramine (15 mg kg-1) SC once daily for 14 days. [125I]Iodocyanopindolol binding to beta 1-adrenergic receptors was found to increase significantly in the caudate-putamen and the somatosensory areas of the frontal cortex after both citalopram and fluoxetine treatments. Imipramine treatment elicited a marked decrease in beta 1 binding in the outer laminae of the cingulate cortex, as well as in the motor and somatosensory areas of the frontal cortex. In a separate experiment, rats were treated with saline, citalopram (2.5, 10 and 20 mg kg-1) or fluoxetine (2.5, 10 and 20 mg kg-1) SC once daily for 14 days. The effects of citalopram and fluoxetine on beta 1 receptors in the somatosensory cortex and caudate-putamen were replicated. These results demonstrate that chronic administration of selective serotonin reuptake inhibitors, in contrast to imipramine, can cause a regional up-regulation of beta 1-adrenergic receptors in the rat brain.
authors.affiliation: Department of Pharmacology, University of Turku, Finland.
authors.forename: E P
authors.initials: EP
authors.lastname: Pälvimäki
authors.forename: A
authors.initials: A
authors.lastname: Laakso
authors.forename: M
authors.initials: M
authors.lastname: Kuoppamäki
authors.forename: E
authors.initials: E
authors.lastname: Syvälahti
authors.forename: J
authors.initials: J
authors.lastname: Hietala
mesh_terms: D058665:Adrenergic beta-1 Receptor Agonists; D000818:Animals; D001345:Autoradiography; D001923:Brain Chemistry / Q000187:drug effects; D015283:Citalopram / Q000494:pharmacology*; D005473:Fluoxetine / Q000494:pharmacology*; D007091:Image Processing, Computer-Assisted; D007099:Imipramine / Q000494:pharmacology; D020120:Iodocyanopindolol; D008297:Male; D010869:Pindolol / Q000031:analogs & derivatives; D051381:Rats; D017207:Rats, Sprague-Dawley; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D058665:Adrenergic beta-1 Receptor Agonists; D015283:Citalopram; D005473:Fluoxetine; D007099:Imipramine; D020120:Iodocyanopindolol; D010869:Pindolol; D017367:Selective Serotonin Reuptake Inhibitors