Assessment of delta opioid agonists BW373U86, SNC80 and SNC162 in the conditioned taste aversion design

Recent development of non-peptide, delta-selective opioidergic compounds has allowed for their assessment within the conditioned taste aversion (CTA) design. The present experiment characterized CTAs produced by opioid agonists varying in their selectivity for the delta receptor. Specifically, rats were given four pairings of a novel saccharin solution with various doses of the delta agonists BW373U86, SNC 80 and SNC 162 (listed in order of increasing delta-selectivity). For comparison, the mu agonist morphine was also assessed. Both the delta compounds and the mu-selective morphine induced aversions; however, those produced by the delta agonists were greater in degree, more rapidly acquired and acquired at lower doses than those induced by morphine. The relative efficacy of a delta compound in the CTA design is inversely related to its relative affinity for the delta receptor. The degree and pattern of CTAs produced by these delta agonists may have implications for their use and potential abuse.