Hypothermic, ACTH, and cortisol responses to ipsapirone in patients with mania and healthy controls.

BACKGROUND

The selective 5-HT1A receptor agonist ipsapirone causes dose-dependent decrease in body temperature and increase in adrenocorticotropic hormone (ACTH) and cortisol release in humans. These responses are attenuated by 5-HT1A receptor antagonists, suggesting that hypothermia, ACTH and cortisol release induced by ipsapirone are indeed mediated by 5-HT1A receptors and that these responses provide a valid index of 5-HT1A receptor function in humans.

METHODS

To examine the 5-HT1A receptor sensitivity in patients with mania, we studied six manic patients and six age and sex matched healthy controls. After obtaining a blood sample for baseline hormone levels and measuring body temperature, a single dose of 0.3 mg/kg of ipsapirone was given orally to all the subjects and further bloods and temperature reading were obtained every 30 minutes for 3 hours.

RESULTS

We found that ACTH and cortisol responses to ipsapirone were significantly increased in mania when compared to healthy controls, but there was no significant difference in hypothermic response to ipsapirone between the two groups.

LIMITATIONS

A lack of placebo control, heterogeneity of patients, and a small sample size are the limitations.

CONCLUSIONS

Our findings suggest that manic patients may have enhanced postsynaptic 5-HT1A receptor sensitivity, but presynaptic 5-HT1A receptors are unaltered in this condition. Further placebo-controlled studies with a larger number of manic patients are needed to verify this.