On the Blood‐Brain Barrier to Peptides: [³H]βCasomorphin‐5 Uptake by Eighteen Brain Regions In Vivo

Abstract

After intracarotid injection of [3H]beta-casomorphin-5 (beta CM5) in rats, the accumulation of radioactivity was determined in 18 brain regions and the anterior pituitary. The relative accumulation in all regions significantly exceeded that of [3H]inulin by a factor of 2.5, indicating a low but measurable brain uptake of the peptide. In blood-brain barrier-free areas, the accumulation of radioactivity was 15-fold higher than in blood-brain barrier-protected areas. The relative accumulation was not dependent on the total beta CM5 concentration in the range of 0.3-1.1 microM, and was not depressed by 400 microM L-tyrosine. We conclude that beta CM5, like other peptides, is accumulated in the blood-brain barrier-free areas to a relatively high but differing degree, whereas in the areas with a tight endothelium the accumulation is relatively low and nearly uniform. A binding to endothelial cells may contribute to the low accumulation of beta CM5, especially in blood-brain barrier-protected areas.

Food-derived opioid peptides inhibit cysteine uptake with redox and epigenetic consequences

“…Recently, it has also been revealed that casein-derived opioid peptides are present in the urine of autistic and schizophrenic subjects, but not of controls (44,45). It has been suggested that increased blood levels of bBCM7, in conjunction with lower activity of dipeptidylpeptidase IV (DPPIV), the enzyme responsible for its hydrolysis, may be associated with apnea in sudden infant death syndrome (SIDS) (45), reflecting µ-receptormediated respiratory depression.…”

Can the Pathophysiology of Autism be Explained by the Nature of the Discovered Urine Peptides?

“…Such acute changes are also seen when opioid drugs are used and could possibly explain periods of hyperactive agitation, aggressive and emotionally bizarre acting out behaviours as well as more catatonic phases. Furthermore, exorphins do pass the blood -brain barrier (Ermisch et al, 1983;Nyberg et al, 1989) and are extremely psychosogenic as seen in postpartum psychosis (Lindstrøm et al, 1984). Exposing the blood-brain barrier to opioids during early growth in rats permanently alters the permeability to opioids in these membranes (Banks et al, 1996).…”

Caseins as source of bioactive peptides

“…Ermisch, Ruhle, Neubert, Hartrodt, and Landgraf (1983) have shown that, following intracarotid injection of [ 3 H]b-casomorphin-5 in rats, this compound accumulated to a relatively high degree in the areas free of blood-brain barrier. Higher amounts of b-casomorphin-7 were also encountered in blood from newborn calves, under the form of a precursor (Fiat et al, 1993).…”