title: Increased delta, but not mu, opiate receptor binding in the medulla oblongata of Long-Evans rats following 5-day water deprivation.
abstract: Opiate receptors of the mu type were labeled with [125I]D-Ala2,N-Me-Phe4,Met-(O)5-ol-enkephalin (FK-33824). delta receptors were labeled with [125I]D-Ala2-D-Leu5-enkephalin (DADLE) in the presence of excess (N-Me-Phe3,D-Pro4)-morphiceptin (PL017). Since DADLE binds mu and delta receptor sites, and PL017 blocks mu receptors, this protocol improves specific labeling of delta receptors. Quantitative autoradiography showed that chronic dehydration causes no changes in mu receptor binding in the medulla oblongata of Long-Evans rats. However, there is increased delta receptor binding in the solitary, hypoglossal and gracilis nuclei, and the spinal nucleus of trigeminal system of dehydrated animals, suggesting that delta opiate receptors participate in the physiological response to dehydration.
mesh_terms: D000818:Animals; D001835:Body Weight; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine; D005247:Feeding Behavior / Q000502:physiology; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000032:analysis* / Q000187:drug effects; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D013997:Time Factors; D014554:Urination; D014868:Water Deprivation / Q000502:physiology*
chemical_list: D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine