In vivo and in vitro effect of imipramine and fluoxetine on Na+, K+-ATPase activity in synaptic plasma membranes from the cerebral cortex of rats
Braz. j. med. biol. res
;
34(10): 1265-1269, Oct. 2001. graf
Article
in English
| LILACS
| ID: lil-299841
RESUMO
The effects of in vivo chronic treatment and in vitro addition of imipramine, a tricyclic antidepressant, or fluoxetine, a selective serotonin reuptake inhibitor, on the cortical membrane-bound Na+,K+-ATPase activity were studied. Adult Wistar rats received daily intraperitoneal injections of 10 mg/kg of imipramine or fluoxetine for 14 days. Twelve hours after the last injection rats were decapitated and synaptic plasma membranes (SPM) from cerebral cortex were prepared to determine Na+,K+-ATPase activity. There was a significant decrease (10 percent) in enzyme activity after imipramine but fluoxetine treatment caused a significant increase (27 percent) in Na+,K+-ATPase activity compared to control (P<0.05, ANOVA; N = 7 for each group). When assayed in vitro, the addition of both drugs to SPM of naive rats caused a dose-dependent decrease in enzyme activity, with the maximal inhibition (60-80 percent) occurring at 0.5 mM. We suggest that a) imipramine might decrease Na+,K+-ATPase activity by altering membrane fluidity, as previously proposed, and b) stimulation of this enzyme might contribute to the therapeutic efficacy of fluoxetine, since brain Na+,K+-ATPase activity is decreased in bipolar patients
Full text:
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Index:
LILACS (Americas)
Main subject:
Synaptic Membranes
/
Cerebral Cortex
/
Fluoxetine
/
Sodium-Potassium-Exchanging ATPase
/
Imipramine
/
Antidepressive Agents
Limits:
Animals
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
2001
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Fundaçäo Universidade do Rio Grande/BR
/
Universidade Federal do Rio Grande do Sul/BR
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