beta-Casomorphins induce apnea and irregular breathing in adult rats and newborn rabbits.

Abstract

Bovine beta-casomorphin, beta-casomorphin, morphiceptin or morphine were administered systemically (i.v. or i.p.) and intracerebroventricularly (lateral or IVth ventricles) to anesthetized adult rats and preterm newborn rabbits. All agents caused dose-related depressions of respiratory frequency and tidal volume. Morphiceptin and beta-casomorphin were approximately equipotent to morphine while beta-casomorphin was 10 times as potent after intracerebroventricular injection. The beta-casomorphins decreased inspiratory drive and prolonged the expiratory phase by delaying the setpoint for inspiration. A respiratory depression could be elicited by systemic administration of morphiceptin but not by beta-casomorphin or beta-casomorphin. All ventilatory effects induced by the beta-casomorphins could be readily reversed or prevented by naloxone. Intracerebroventricular but not intraperitoneal injection of beta-casomorphin depressed ventilation in preterm newborn rabbits in a similar pattern with apnoic periods to that seen in the adult rats. In addition, an irregular breathing pattern was elicited. Thus, the bovine beta-casomorphins possess potent central respiratory depressive effects. However, after systemic administration, only morphiceptin which is more metabolically stable induced a shortlasting effect on ventilation in adult rats.

• Authors: J Hedner, T Hedner
• Journal: Life sciences (Life Sci) Vol. 41 Issue 20 Pg. 2303-12 (Nov 16 1987) ISSN: 0024-3205 [Print] Netherlands
• PMID: 3683078 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Endorphins
• beta-casomorphins

Topics

• Amino Acid Sequence
• Animals
• Animals, Newborn
• Apnea (chemically induced)
• Cattle
• Endorphins (pharmacology)
• Humans
• Rabbits
• Respiration (drug effects)