Hormonal responses to the 5-HT1A agonist buspirone in remitted endogenous depressive patients after long-term imipramine treatment

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• 作者：Esther Gó ; mez-Gil ; Ricard Naviné ; s ; M. Jesú ; s Martí ; nez De Osaba ; Maribel Dí ; az-Ricart ; Giné ; s Escolar ; Manel Salamero ; Rocí ; o Martí ; n-Santos ; Ana Galá ; n ; Crist
• 关键词：Major depression ; Endogenous ; Serotonin ; 5-HT1A receptor ; Buspirone challenge ; Antidepressant treatment ; Imipramine
• 刊名：Psychoneuroendocrinology
• 出版年：2010
• 出版时间：May 2010
• 年：2010
• 卷：35
• 期：4
• 页码：481-489
• 全文大小：265 K

文摘

Summary

Introduction

The serotonin-1A (5-HT1A) receptor subtypes are considered as targets of a variety of antidepressant drugs. Previous studies have suggested different adaptive changes in pre- and post-synaptic 5-HT receptors in the brain after treatment with non-selective tricyclic antidepressants (TCA) and selective 5-HT re-uptake inhibitors (SSRIs). The present study aimed to investigate the adaptive effect of the TCA imipramine on the post-synaptic 5-HT1A receptor function in the hypothalamus.

Methods

A longitudinal design was used in 14 patients with major depressive disorder (DSM-IV) with endogenous features (Newcastle Scale) in order to assess the functional status of post-synaptic 5-HT1A receptors before and after successful antidepressant treatment with imipramine. The effect of the 5-HT1A receptor agonist, buspirone, on ACTH, cortisol, and prolactine (PRL) plasma levels was used to assess the functional status of hypothalamic 5-HT1A receptors. A group of 15 concurrent normal subjects were used as control.

Results

Endogenous depressed patients in remission and currently receiving treatment with imipramine (mean length of treatment 145 days, SD = 27) presented significantly lower buspirone responses to ACTH and cortisol than in the pre-treatment condition (Δmax p ≤ .05; AUC p < .001) and to ACTH in comparison with healthy controls (Δmax p < .01; AUC p < .05). No significant differences were found between the post-treatment and pre-treatment PRL responses, or between patients in both conditions and controls; nevertheless, the PRL response in patients in remission and receiving treatment almost reached the values seen in controls.

Conclusions

This study extends previous findings from our group using the SSRI citalopram as an antidepressant. Imipramine and citalopram induce similar changes in the endocrine response to buspirone in depressed patients. As the direction of change in ACTH–cortisol and PRL responses after treatment is the opposite, we cannot substantiate increases or decreases in the sensitivity of post-synaptic 5-HT1A receptors in the hypothalamus by long-term imipramine treatment and/or resolution of illness. Therefore, the hormonal changes may result from different or multiples unknown mechanisms.