gamma-endorphin and Anaphylaxis

The pathophysiological consequences of endorphin release in anaphylactic shock were investigated through pharmacological studies using opiate antagonists (naloxone, naltrexone, natrexone methyl bromide) as well as agonists (morphine, beta-endorphin). These studies suggest that induction of anaphylaxis provokes the release of endogenous opioids, possibly from the hypothalamus, which contribute to the shock process by stimulating opiate receptors in the CNS. The mechanism of pathophysiologic action of endorphin in anaphylaxis involves, at least in part, inhibition of the central component of the sympatho-adrenalmedullary system. This results in reduced effectiveness of the sympathetic system to physiologically reverse the circulatory effects of the toxic mediators of anaphylaxis. Naloxone, by blocking endorphin action at CNS opiate receptors located at autonomic regulatory centers (e.g. hypothalamus), reverses the sympatho-inhibitory effect of the endorphin peptides. This results in increased central sympathetic outflow to peripheral sympathetic neuroeffector mechanisms; it affords improved sympathetic compensatory responses and increases survival. TRH and DT gamma E physiologically oppose the action of endorphins upon the autonomic system. They stimulate central sympathetic mechanisms through their own receptor systems and increase outflow to peripheral sympathetic effectors. This also results in improved circulatory function and survival.

Topics: Anaphylaxis; Animals; Catecholamines; Endorphins; gamma-Endorphin; Mice; Naloxone; Receptors, Opioid; Sympathetic Nervous System; Thyrotropin-Releasing Hormone

gamma-Endorphin-type peptides (i.e. gamma-endorphin, des-tyr'-gamma-endorphin [DT gamma E]) result from the processing of the opioid peptide, beta-endorphin. Previous studies have implicated the involvement of beta-endorphin in various types of shock, including anaphylactic shock. In the present experiments the intracerebroventricular (i.c.v.) administration of gamma-endorphin (10 micrograms) or DT gamma E (3.3-10 micrograms) significantly improved survival in anaphylactic shock in mice. Moreover, DT gamma E (10 micrograms) reversed the effect of i.c.v. beta-endorphin (3.3 micrograms) to exacerbate shock. A similar dose of DT gamma E was ineffective in antagonizing beta-endorphin-induced analgesia. The anti-anaphylactic action of DT gamma E as well as its effect to block the pro-anaphylactic action of beta-endorphin were prevented by pretreatment with the sympathetic ganglionic blocker, chlorisondamine chloride. The results suggest that gamma-endorphin-type peptides may act in the central nervous system (CNS) to physiologically oppose the autonomic pathophysiologic influences of beta-endorphin.

Topics: Anaphylaxis; Animals; beta-Endorphin; Chlorisondamine; Drug Interactions; Endorphins; gamma-Endorphin; Male; Mice; Mice, Inbred ICR; Naloxone; Peptide Fragments; Serum Albumin, Bovine; Sympathetic Nervous System