H2-receptor-mediated stress-induced analgesia is dependent on neither pituitary nor adrenal activation

The effects of hypophysectomy and adrenalectomy were studied on the analgesia elicited by a 3 min exposure to 3.5 mA of continuous inescapable footshock, a response previously shown to be resistant to high doses of the opiate antagonist, naloxone, but inhibited by antagonists of histamine H2-receptors. Neither treatment significantly attenuated the response, and the brain-penetrating H2-receptor antagonist zolantidine inhibited the response in all surgical treatment groups. These results add further support for our hypothesis that brain histamine and brain H2-receptors mediate nonopiate analgesia.