5-HT1A receptor function in normal subjects on clinical doses of fluoxetine: blunted temperature and hormone responses to ipsapirone challenge.
Neuropsychopharmacology
; 20(6): 628-39, 1999 Jun.
Article
em En
| MEDLINE
| ID: mdl-10327431
ABSTRACT
Serotonergic receptors of the 5-HT1A subtype have been suggested to play a pivotal role in the mechanism of action of antidepressant drugs, including specific serotonin reuptake inhibitors (SSRIs). We examined the effect of clinical doses of the SSRI, fluoxetine, on 5-HT1A receptor function in 15 normal volunteers. Hypothermic and hormone responses to the 5-HT1A receptor agonist, ipsapirone (0.3 mg per kg, per os) were examined after two weeks of placebo and again, after the subjects had been receiving fluoxetine for four weeks. On fluoxetine, the hypothermic response to ipsapirone was significantly blunted, as were ACTH, cortisol and growth hormone release. Ipsapirone plasma levels were significantly increased by fluoxetine but a pharmacokinetic effect could not have accounted for the observed blunting of 5-HT1A receptor mediated effects. These findings confirm and extend previous observations in rodents and humans and indicate that both post-synaptic 5-HT1A receptors in the hypothalamus, which mediate hormone responses to 5-HT1A agonists, and pre-synaptic 5-HT1A receptors which (putatively) mediate the hypothermic response, are rendered subsensitive by chronic SSRI administration. Since fluoxetine did not have significant effects on mood and other psychological variables in these subjects, alterations in 5-HT1A receptor function induced by SSRIs may have psychotropic relevance only in the context of existing perturbations of serotonergic function which underlie the psychopathological states in which these drugs are therapeutically effective.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pirimidinas
/
Fluoxetina
/
Receptores de Serotonina
/
Inibidores Seletivos de Recaptação de Serotonina
/
Agonistas do Receptor de Serotonina
Tipo de estudo:
Clinical_trials
Limite:
Adult
/
Female
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Humans
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Male
/
Middle aged
Idioma:
En
Ano de publicação:
1999
Tipo de documento:
Article