Oxytocin as a possible mediator of SSRI-induced antidepressant effects

Abstract

The nonapeptide oxytocin is released into systemic circulation in situations of psychosocial interaction, and has been shown to be involved in mechanisms of social bonding and social recognition in laboratory studies. In view of disturbances in psychosocial relationships being a triggering factor for depression and anxiety, it is interesting to note that experimental studies have shown oxytocin to possess antidepressant- and anxiolytic-like actions. Thus. in the present study we examined effects of the SSRI citalopram (20 mg/kg i.p.) on plasma oxytocin, acutely and upon repeated administration, in adult male Sprague-Dawley rats. Plasma oxytocin, and some functionally related peptides (CCK, gastrin, somatostatin and insulin), were measured by standard radioimmunoassay techniques. Acute citalopram administration produced a statistically significant increase in plasma oxytocin and CCK levels. Administration of citalopram for 14 days did not attenuate the oxytocin-releasing effect to a challenge dose of the SSRI zimeldine (20 mg/kg s.c.), whereas CCK levels were not increased after the subchronic citalopram treatment. Thus, the SSRI citalopram produces increased plasma oxytocin levels acutely, and there appears to be no or little tolerance to this effect upon repeated administration. There were no, or variable, effects on plasma levels of gastrin, somatostatin or insulin. It is suggested that oxytocin release is an important aspect of the pharmacological actions of SSRIs, and this could be an important contributory factor for the clinical profile of this group of antidepressants with particular efficacy in disorders of psychosocial origin.

Negative correlation between cerebrospinal fluid oxytocin levels and negative symptoms of male patients with schizophrenia

“…Since the CSF oxytocin levels were not normally distributed, log transformation was applied prior to statistical analyses to achieve normal distribution. Because previous studies suggest that some antipsychotic and antidepressant medications increase oxytocin secretion (Uvnas-Moberg et al, 1992;Uvnas-Moberg et al, 1999), chlorpromazine and imipramine equivalent doses were examined as possible confounders. Statistical analyses were performed using the Statistical Package for the Social Sciences version 11.0 (SPSS Japan, Tokyo, Japan).…”

Plasma oxytocin levels and anxiety in patients with major depression

“…Oxytocin fibers project to the raphe nuclei and OT may influence the secretion of 5-HT. Recent studies have demonstrated that OT is released in response to treatment with selective serotonin reuptake inhibitors (SSRI), opening up the possibility that OT also mediate further effects caused by serotonin (Uvnas-Moberg et al, 1999).…”

Oxytocin, vasopressin, and human social behavior

“…Numerous studies on the inhibitory influence of OT on stress-responsive neurohormonal systems focused on the endogenous stimulation of OT during lactation in rodents. The suckling stimulus by the newborn was found to increase OT release and decrease basal plasma levels of ACTH and cortisol [26,27,121,148,149,160].…”