title: Chronic fluoxetine treatment alters cardiovascular functions in unanesthetized rats.
abstract: In the present study, we investigated the effects induced by fluoxetine treatment (10 mg/kg) for either 1 or 21 consecutive days on arterial pressure and heart rate basal levels, baroreflex activity, hemodynamic responses to vasoactive agents and cardiovascular responses to acute restraint stress. Mild hypertension was observed after 21 days of treatment, but not after administration for 1 day. Moreover, chronic treatment affected the baroreflex control of heart rate, which was characterized by a reduced reflex tachycardia and an enhanced bradycardiac baroreflex response. The pressor responses to systemic administration of the selective α(1)-adrenoceptor agonist phenylephrine, as well as the depressor responses to systemic infusion of the nitric oxide donor sodium nitroprusside, were reduced after chronic fluoxetine treatment. Fluoxetine treatment for 21 days reduced both the pressor and tachycardiac responses evoked by acute restraint stress. In conclusion, the results indicate the development of mild hypertension after chronic fluoxetine treatment. This effect was followed by changes in the baroreflex control of heart rate and altered vascular responsiveness to pressor and depressor agents, which may explain, at least in part, the increase in arterial pressure. Chronic fluoxetine treatment also affected cardiovascular responses to restraint stress, thus indicating that fluoxetine may affect cardiovascular adaptation under conditions of stress.
authors.affiliation: Department of Natural Active Principles and Toxicology, School of Pharmaceutical Sciences of Araraquara, São Paulo State University, UNESP, SP, 14801-902, Brazil.
authors.forename: Carlos C
authors.initials: CC
authors.lastname: Crestani
authors.forename: Rodrigo F
authors.initials: RF
authors.lastname: Tavares
authors.forename: Franscisco S
authors.initials: FS
authors.lastname: Guimarães
authors.forename: Fernando M A
authors.initials: FM
authors.lastname: Correa
authors.forename: Sâmia R L
authors.initials: SR
authors.lastname: Joca
authors.forename: Leonardo B M
authors.initials: LB
authors.lastname: Resstel
mesh_terms: D000818:Animals; D017704:Baroreflex / Q000187:drug effects; D001481:Basal Metabolism / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D002319:Cardiovascular System / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005473:Fluoxetine / Q000008:administration & dosage* / Q000009:adverse effects*; D006339:Heart Rate / Q000187:drug effects; D009599:Nitroprusside / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical / Q000009:adverse effects; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects*; D013315:Stress, Psychological / Q000209:etiology / Q000503:physiopathology; D013997:Time Factors
chemical_list: D005473:Fluoxetine; D009599:Nitroprusside; D010656:Phenylephrine; D017367:Selective Serotonin Reuptake Inhibitors