Na+-dependent high affinity binding of [3H]LY515300, a 3,4-dimethyl-4-(3-hydroxyphenyl)piperidine opioid receptor inverse agonist.
Analogues of 3,4-dimethyl-4-(3-hydroxyphenyl)piperidines are high affinity inverse agonists for micro-, delta- and kappa-opioid receptors. To characterize inverse agonist binding, we synthesized a high specific activity radioligand from this series, [3H]LY515300 (3-[1-((3-cyclohexyl-[3,4-3H(2)])-3(R,S)-hydroxypropyl)-3(R),4(R)-dimethylpiperidin-4-yl]phenol). In membranes expressing cloned human opioid receptors, [3H]LY515300 binding was saturable and exhibited low nonspecific binding. [3H]LY515300 bound with high affinity to the micro- (K(d)=0.07 nM), delta- (K(d)=0.92 nM) and kappa-(K(d)=0.45 nM) opioid receptors. High affinity [3H]LY515300 binding to all opioid receptors was Na(+)-dependent, a characteristic of inverse agonists. Displacement by standard opioid compounds yielded K(i) values consistent with their known opioid receptor affinities. Autoradiographic localization of specific [3H]LY515300 binding in rat and guinea pig brain was high in areas known to express high levels of opioid (particularly micro-opioid receptor) binding sites including the caudate, nucleus accumbens, and nucleus tractus solitarius. Thus, [3H]LY515300 is the first radiolabeled opioid receptor inverse agonist useful for the study of opioid receptors in cell lines and native tissues.
Statnick
Michael A
MA
Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285-0403, USA. m.statnick@lilly.com
Suter
Todd M
TM
Gackenheimer
Susan L
SL
Emmerson
Paul J
PJ
Quimby
Steve J
SJ
Gehlert
Donald R
DR
Wheeler
William J
WJ
Mitch
Charles H
CH
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D016466:CHO Cells; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006801:Humans; D008297:Male; D010880:Piperidines / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000819:agonists* / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism* / Q000494:pharmacology; D014316:Tritium / Q000378:metabolism
C488414:3,4-dimethyl-4-(3-hydroxyphenyl)piperidine; D010880:Piperidines; D011957:Receptors, Opioid; D014316:Tritium; D012964:Sodium