Binding characteristics of [D-Ala2-MePhe4-Glyol5] enkephalin and [D-Pen2,D-Pen5] enkephalin in rat brain: inhibition studies with fentanyl-like drugs.
We have investigated the binding characteristics of two tritiated enkephalin analogues [D-Ala2-MePhe4-Glyol5] enkephalin (DAGO) and [D-Pen2, D-Pen5] enkephalin (DPDPE) which are highly selective for mu and delta opioid sites respectively, in homogenates of whole rat brain and of the pons/medulla region. In addition, we have explored the binding profile of four 4-anilinopiperidine drugs (fentanyls) by means of inhibition studies. Our studies show that the delta involvement in pons/medulla of rat is small compared with that in whole brain and with mu binding in both whole brain and pons/medulla. In addition the rank order of affinities of the fentanyl series is the same at the mu and delta site, but the affinities are between 1 and 600-fold greater at the former site.
Yeadon
M
M
Department of Biochemistry, University of Surrey, Guildford, U.K.
Kitchen
I
I
D000818:Animals; D001921:Brain / Q000378:metabolism*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000378:metabolism*; D005283:Fentanyl / Q000031:analogs & derivatives* / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects / Q000378:metabolism*; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu
D004745:Enkephalins; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D005283:Fentanyl