Opioid binding in a rat neurohypophysial fraction enriched in oxytocin and vasopressin nerve endings.
Binding of the opiate antagonists [3H]diprenorphine and [3H]naloxone and of the opioid agonists [3H]Met-enkephalin and [3H]dynorphin(1-8) was studied in a fraction of the rat neurohypophysis containing disconnected oxytocin and vasopressin nerve endings ('neurosecretosomes'). There was specific binding of [3H]diprenorphine in the fraction enriched with neurosecretosomes. This binding was only partially displaceable by naloxone; naloxone binding was stereospecific. Intact and unoxidized [3H]Met-enkephalin was found in the neurosecretosome pellet; binding of the analogue D-Ala-D-Leu-enkephalin was very low. Our data favour the assumption of a direct action of endogenous opioids at the neurosecretory nerve endings.
Falke
N
N
Martin
R
R
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D001665:Binding Sites; D004174:Diprenorphine / Q000378:metabolism; D004399:Dynorphins / Q000378:metabolism; D004723:Endorphins / Q000378:metabolism*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine; D004744:Enkephalin, Methionine / Q000378:metabolism; D008297:Male; D009270:Naloxone / Q000378:metabolism; D010121:Oxytocin / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D051381:Rats
D004723:Endorphins; D010446:Peptide Fragments; D001127:Arginine Vasopressin; D004174:Diprenorphine; D009270:Naloxone; D010121:Oxytocin; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; D004399:Dynorphins; C026770:dynorphin (1-8)