Trial-selective effects of U50,488H, a kappa-opioid receptor agonist, on consummatory successive negative contrast.
A series of experiments studied the effects of the kappa-opioid receptor agonist U50,488H on consummatory successive negative contrast (cSNC) in rats. In cSNC, previous experience with a 32% sucrose solution leads to greater rejection of 4% sucrose than exclusive experience with 4% sucrose. Experiments 1 and 2 revealed that U50,488H failed to influence cSNC when administered before the first downshifted trial, but either attenuated (1mg/kg) or enhanced (3 and 10mg/kg) cSNC when administered before the second downshift trial. Experiment 3 showed that U50,488H administered immediately after the first downshift trial had no effect on cSNC at the 1mg/kg dose, but tended to increase cSNC at the 3mg/kg dose. However, Experiment 4 suggested that the apparent enhancement of cSNC after 3mg/kg U50 administered posttrial 11 may have reflected the development of a conditioned taste aversion. The trial-selective attenuating effect of the low dose may reflect an anxiolytic-like property of U50,488H.
Department of Psychology, Texas Christian University, Box 298920, Fort Worth, TX 76133, USA.
Michael D
MD
Wood
Jacob N
JN
Norris
Alan M
AM
Daniel
Mauricio R
MR
Papini
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / Q000008:administration & dosage / Q000494:pharmacology*; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D003259:Consummatory Behavior / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D007274:Injections, Intraperitoneal; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D017473:Receptors, Opioid, kappa / Q000819:agonists*
D018712:Analgesics, Non-Narcotic; D017473:Receptors, Opioid, kappa; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer