Central administration of the endopeptidase 24.15 inhibitor cFP-AAF-pAB suggests dynorphin as the endogenous ligand underlying behavioral effects of milk in the fetal rat.
Intraoral infusion of milk to the rat fetus promotes opioid activity that results in reduced responsiveness in a behavioral bioassay involving perioral cutaneous stimulation. Intracisternal administration of cFP-AAF-pAB, an inhibitor of endopeptidase 24.15, prolonged the opioid activity induced by milk infusion. Treatment with the selective kappa opioid antagonist nor-binaltorphimine blocked the effect of cFP-AAF-pAB on milk-induced opioid activity, but treatment with the mu antagonist CTOP or the delta antagonist naltrindole did not. These findings imply that milk may exert its effect on fetal behavior by increasing levels of dynorphin in the fetal central nervous system.
Smotherman
W P
WP
Department of Psychology, State University of New York at Binghamton 13902-6000.
Robinson
S R
SR
Varlinskaya
E I
EI
Petrov
E S
ES
Orlowski
M
M
de Costa
B R
BR
Rice
K C
KC
D000595:Amino Acid Sequence; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D002946:Cisterna Magna; D004399:Dynorphins / Q000502:physiology*; D005260:Female; D005333:Fetus / Q000502:physiology*; D007267:Injections; D008024:Ligands; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D008892:Milk / Q000502:physiology*; D008969:Molecular Sequence Data; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009842:Oligopeptides / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010812:Physical Stimulation; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013004:Somatostatin / Q000031:analogs & derivatives / Q000494:pharmacology
D008024:Ligands; D009292:Narcotic Antagonists; D009842:Oligopeptides; C049352:phenylalanyl-cyclo(cysteinyltyrosyl-tryptophyl-ornithyl-threonyl-penicillamine)threoninamide; C064939:N-(1-carboxy-3-phenylpropyl)-alanyl-alanyl-phenylalanine-4-aminobenzoate; C051844:norbinaltorphimine; D013004:Somatostatin; D009271:Naltrexone; D004399:Dynorphins; D008666:Metalloendopeptidases; C022510:thimet oligopeptidase; C055382:naltrindole