Corticotropin and cortisol secretion after central 5-hydroxytryptamine-1A (5-HT1A) receptor activation: effects of 5-HT receptor and beta-adrenoceptor antagonists.

To explore the involvement of 5-hydroxytryptamine-1A (5-HT1A) receptors in hypothalamic-pituitary-adrenal (HPA) axis regulation, various doses of ipsapirone (IPS), a centrally acting pyrimidinylpiperazine with considerable affinity and selectivity for 5-HT1A recognition sites, were administered to normal subjects. IPS dose-dependently increased plasma ACTH concentrations from -78 +/- 63 to 614 +/- 250 pmol.min/L (P less than 0.

Pharmacology of the hypothermic response to 5-HT1A receptor activation in humans.

The selective 5-HT1A receptor ligand ipsapirone (IPS) caused dose-related hypothermia in humans. The response was attenuated by the nonselective 5-HT1/2 receptor antagonist metergoline and was completely antagonized by the nonselective beta-adrenoceptor antagonist pindolol, which interacts stereoselectively with the 5-HT1A receptor. The selective beta 1-adrenergic antagonist betaxolol had no effect.