Effects of beta-casomorphins on neuronal survival in culture of embryonic chick dorsal root ganglion neurons

We studied the effects of beta -casomorphins (beta -CMs, mu -acting opioid peptides from milk protein beta -casein) on survival of primary-cultured ch ick dorsal root ganglion neurons in the presence of nerve growth factor. be ta -CM-5 and beta -CM-7 had potent neuronal survival-promoting activities. beta -CM-4 amide (morphiceptin) and des-Tyr(1)-beta -CM-7 also exhibited th e similar promoting effects, although their effects were very weak. The pro moting effect of beta -CM-5 was prevented by co-administration of naloxone, or pretreatment with pertussis toxin. These results suggest that the neuro nal survival-promoting effects of beta -CMs might be mediated through opioi d receptors coupled to G proteins.