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UEE OF A EEIZIVIDAZCLE DERIVATIVE WITH POTENT MCRPHINE-LIHE
PROPERTIES CRALLY AS A PSESUMFTIVE PSINFORCER IN CONDITICNING OF CRUO-SECKIRG SEHAVIOR IN RATS. AFShER SIRIEC, PNLILIO C. Grzen, Harbart C. Seith\* d Frank T. Pezcor. Nldi Addietien Resaarch Ceater, USpHS Hiapital, Lexington, Kentucky.
when vater -neprived, poa-asoleted rets (C) and rsts (E)
sterlllzed en 200 sg/'ng ef rerphins s.c. oncs daily (tested
18m22 hrs abatinezt) drank e 5 meg/al equects solutica 05 le Gete-diethylerinoathyl)-2-(p-thoxybenzyl)-5-nitrobeasinisazdle mathane stlfonate (Ic2) avidly, and exhicited morphineslike
effects eithia L-7 mir. (66-ihi sec/kg ingasted), vith cessaticn of spontanesus skir twitches (ebstinence sign) ln E. During the first 3 sin, latragroep differences beteeen.relative amcunts of lG2 and tap water consumed lroo elther of 2 drinking tubes wsrs not sigaifisent, rogerdless of side piacereat of IG2, izdie cating inability of C or E to discrisizate by taste alone.
Training by pairing effect of IG2 with diseriminatory stizali (Do) i3 aov in progreso. Sizilar C and E were traiaed to operate a lover tor lG2 or sater teaaros (with DS) when waterwleprived (/D) and vaterugatiatei (ws), all four conditions rendonised and
belancad. Ca wS days, freqssncies (f) of lever-prtaslng for IC2 eera cignificeatly hicher la E than C, saggestiag aequisitioa ul prefarercs by S, but iatregonp differeness for lo2 or weten w net afcntiicnat. intergroup cotparizens or f andss ceatiazruo eto at intervss ofter sreaiaesitnarent t 2 ts

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