Effect of social isolation on corticosterone secretion elicited by histaminergic stimulation

Social stress of crowding for 3, 7, 14 and 21 days drastically reduces the serum corticosterone response to intracerebroventricular administration of dimaprit, a histamine H₂-receptor agonist, moderately diminishes the response to pyridylethylamine, an H₁-receptor agonist, and does not change significantly the corticosterone response to histamine.

These results suggest that social stress of crowding considerably desensitizes central histamine H₂-receptors involved in stimulation of the hypothalamic-pituitary-adrenal axis.