beta-Casomorphins (beta-CMs) are peptidic fragments of bovine beta-casein with potent opioid activity. In view of a possible physiological meaning of these milk-derived compounds, we have studied the affinity of some natural beta-CMs and some semisynthetic analogues for mu-, delta- and kappa-brain opioid receptors in newborn and adult rat. Moreover we have investigated whether a chronic treatment with the potent analogue D-Ala2-beta-CM-4-NH2 during the suckling period could affect mu and delta opioid receptor function. Our findings demonstrate that beta-CMs are mu-oriented compounds both in adult and in newborn rat brain. They display the same mu-affinity in newborn as well as in adult animals, however delta and kappa-affinities appear different, probably due to the lower degree of maturation of these two receptors in the first days of life. A prolonged treatment with D-Ala2-beta-CM-4-NH2 during the preweanling period is able to induce a delay in the ontogenetic increase of delta-receptor affinity, whereas it affects neither the affinity nor the density of mu-receptors. This effect could be related to a general action of opioids on cerebral maturative processes; moreover we point out that a beta-CMs analogue, given orally to newborn animals, can induce modifications at central level, suggesting thus the hypothesis that beta-CMs could be a biologically active peptide in the first stages of life.
Interaction of beta-casomorphins with multiple opioid receptors: in vitro and in vivo studies in the newborn rat brain / A. Volterra, P. Restani, N. Brunello, C. L. Galli, G. Racagni. - In: BRAIN RESEARCH. - ISSN 0006-8993. - 395:1(1986 Nov), pp. 25-30-30.
|Titolo:||Interaction of beta-casomorphins with multiple opioid receptors: in vitro and in vivo studies in the newborn rat brain|
RESTANI, PATRIZIA (Secondo)
GALLI, CORRADO LODOVICO (Penultimo)
RACAGNI, GIORGIO ANGELO (Ultimo)
|Parole Chiave:||Animals; Receptors, Opioid, mu; Brain; Receptors, Opioid, kappa; Endorphins; Structure-Activity Relationship; Rats; Rats, Inbred Strains; Animals, Newborn; Binding, Competitive; Receptors, Opioid; Receptors, Opioid, delta; Male|
|Settore Scientifico Disciplinare:||Settore BIO/14 - Farmacologia|
Settore CHIM/10 - Chimica degli Alimenti
|Data di pubblicazione:||nov-1986|
|Appare nelle tipologie:||01 - Articolo su periodico|