Simultaneous measurement of cholecystokinin- and vasoactive intestinal polypeptide-like immunoreactivity from cat frontal cortex in vitro: effect of morphine and D-Ala2-D-Leu5-enkephalin.
The two peptides vasoactive intestinal polypeptide (VIP) and cholecystokinin (CCK) have been demonstrated to be discretely distributed in the cerebral cortex. This distribution closely parallels the distribution of mu- and delta-opiate receptors in the frontal cortex. The basal efflux and potassium-stimulated release of VIP- and CCK-immunoreactivity was studied in the presence and absence of morphine and D-Ala2-D-Leu5-enkephalin (DADL), agents with relative affinity for the mu and delta receptors, respectively. The basal efflux of VIP- and CCK-immunoreactivity was not affected by these opiates; however, the potassium-stimulated release of VIP-immunoreactivity was profoundly inhibited in a dose-dependent manner by both morphine (ED50 = 1 X 10(-9) M) and DADL (ED50 = 3.02 X 10(-9) M). The inhibition produced by either morphine or DADL was shown to be reversed by naloxone.
D000818:Animals; D002415:Cats; D002766:Cholecystokinin / Q000378:metabolism*; D003917:Dextrorphan / Q000008:administration & dosage; D004347:Drug Interactions; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine / Q000031:analogs & derivatives*; D005625:Frontal Lobe / Q000378:metabolism*; D007981:Levorphanol / Q000008:administration & dosage; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000008:administration & dosage; D011188:Potassium / Q000008:administration & dosage; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D003917:Dextrorphan; D007981:Levorphanol; D009270:Naloxone; D014660:Vasoactive Intestinal Peptide; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; C030279:enkephalinamide-Leu, Ala(2)-; D009020:Morphine; D002766:Cholecystokinin; D011188:Potassium