Thermal effect induced by anandamide is dissociated of locomotor and feeding behavior (1105.5)

Abstract

The endocannabinoid system has an important role on thermal control and modulates behaviors that may affect the body temperature (Tb), such as locomotion and food intake (FI). In order to test whether changes on Tb induced by anandamide (AEA) are related with behavioral changes, rats received an i.c.v. injection of AEA (0.1, 1.0 and 10.0 μg) and vehicle. Total FI was daily weighted, and both Tb and spontaneous locomotor activity (SLA) were simultaneous and continuously recorded. AEA induced increase on Tb without changes on SLA and FI. For all doses tested, the Tb average at post‐injection period was higher than pre‐injection period. Higher termal effect was verified by 10.0 μg of AEA, starting within the first hour post‐injection, being maintained for 8 hours after treatment. At the first hour, a dose‐dependent thermal effect was observed (r = 0.953; p<0.05). Hypoactivity was verified only for 1.0 μg of AEA. As expected, both Tb and SLA values at dark phase were always higher than at light phase with a positive correlation between them (r = 0.834, p<0.001), however this correlation was inverted (r = ‐0.852, p<0.01) after 10.0 μg of AEA. In summary, our results suggest that brain AEA induces increase of Tb, and this effect may occur independently of changes in both locomotion and FI. Moreover, it is possible that hypolocomotion induced by AEA could be an adaptive response due to increased Tb.Grant Funding Source: CNPQ, Capes and Fapemig