Nucleus accumbens dopaminergic neurotransmission switches its modulatory action in chronification of inflammatory hyperalgesia

摘要: Dopaminergic neurotransmission in the nucleus accumbens, a central component of mesolimbic system, has been associated with acute pain modulation. As there is transition from to chronic (‘chronification’), modulatory structures may be involved development. Thus, this study aimed elucidate role accumbens dopaminergic chronification pain. We used rat model which daily subcutaneous injection prostaglandin E2 hindpaw for 14 days induces long-lasting state nociceptor sensitization that lasts at least 30 following end treatment. Our findings demonstrated increase dopamine by local administration GBR12909 (0.5 nmol/0.25 lL), reuptake inhibitor, blocked E2-induced hyperalgesia. This blockade was prevented D2 receptor antagonist (raclopride, 10 lL) but not changed D1 (SCH23390, 0.5, 3 or both co-administered accumbens. In contrast, induction persistent hyperalgesia facilitated continuous infusion (0.021 nmol/ 0.5 lL/h) over 7 The development impaired SCH23390 (0.125 nmol/0.5 and raclopride (0.416 lL/h), administered continuously days. Taken together, our data suggest involves plasticity switches its antinociceptive pronociceptive.