Involvement of cannabinoid type 1 receptor in fasting-induced analgesia.

摘要: The endocannabinoid system (ECS) is known to modulate not only food intake but also pain, especially via the cannabinoid type 1 receptor (CB1R) expressed throughout central nervous and peripheral tissues. Our previous study demonstrated that fasting produces an analgesic effect in adult male mice, which reversed by intraperitoneal (i.p.) administration of CB1R antagonist (SR 141716). In present study, we further examined formalin-induced inflammatory pain model, i.p. peripherally restricted (AM 6545) fasting-induced analgesia. However, intraplantar SR 141716 did affect Furthermore, mRNA expression change formalin model dorsal root ganglia. c-Fos at spinal cord level was affected fasting, vivo recording from superficial horn lumbar revealed neural activity, indicates minimal involvement Finally, when performed subdiaphragmatic vagotomy block hunger signal gastrointestinal (GI) system, AM 6545 analgesia, still Taken together, our results suggest both CB1Rs contribute effects GI transmit signals brain, rather than those sensory neurons, may effects.