Effect of intraventricular serotonin on the plasma cortisol response to restraint stress in unanesthetized sheep.

Serotonin infused into a lateral ventricle of unanesthetized sheep reduced the response of the hypothalamic-pituitary-adrenal axis to restraint stress. However, the attenuation of the adrenal response by serotonin was of only limited duration, suggesting that pharmacological manipulation of serotonin would not be effective in altering the adrenal response to stress.