Endocannabinoid-Enhanced “Liking” in Nucleus Accumbens Shell Hedonic Hotspot Requires Endogenous Opioid Signals

Abstract Introduction: Stimulating either endogenous cannabinoids or opioids within a restricted dorsomedial “hedonic hotspot” in nucleus accumbens (NAc) shell enhances hedonic impact, or “liking” reactions to sweet tastes. In this study, we probed within this hotspot the relationship between endocannabinoid and opioid signals in hedonic enhancement. Materials and Methods: Specifically, we asked whether enhancement of sucrose “liking” by intra-NAc microinjections of the endocannabinoid anandamide requires concurrent endogenous opioid signaling. Results: Co-administration of the opioid antagonist naloxone in the same NAc