Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
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Neuropsychopharmacology · Nov 2007
Endocannabinoid hedonic hotspot for sensory pleasure: anandamide in nucleus accumbens shell enhances 'liking' of a sweet reward.
Cannabinoid drugs such as Delta9-THC are euphoric and rewarding, and also stimulate food intake in humans and animals. Little is known about how naturally occurring endogenous brain cannabinoids mediate pleasure from food or other natural sensory rewards. The taste reactivity paradigm measures effects of brain manipulations on affective orofacial reactions to intraorally administered pleasant and unpleasant tastes. ⋯ Anandamide produced especially intense hedonic enhancement in a roughly 1.6 mm3 'hedonic hotspot' in dorsal medial shell, where anandamide also stimulated eating behavior. These results demonstrate that endocannabinoid signals within medial accumbens shell specifically amplify the positive hedonic impact of a natural reward (though identification of the receptor specificity of this effect will require future studies). Identification of an endocannabinoid hotspot for sensory pleasure gives insight into brain mechanisms of natural reward, and may be relevant to understanding the neural effects of cannabinoid drugs of abuse and therapeutic agents.