The N-acylethanolamines (NAEs) exert important behavioral, physiological and immunological effects through actions atcannabinoid and other receptors. We measured concentrations of three NAEs, the K_m and V_max for fatty acid amide (FAAH) hydrolysis, FAAH protein and FAAH mRNA in prefrontal cortex, hippocampus, hypothalamus, amygdala, striatum and cerebellum at 4 hour intervals, starting at 0300. Significant differences in N-arachidonylethanolamine (AEA) contents among the times examined occur in the prefrontal cortex (PFC), hippocampus, hypothalamus and striatum. N-Oleoylethanolamine (OEA) concentrations exhibit large fluctuations over the day in the cerebellum, including a three-fold decrease between 1900 and 2300. N-Palmitoylethanolamine (PEA) and OEA were significantly, positively correlated in all regions examined except the hypothalamus. Although FAAH K_m values are significantly affected by time of day in PFC, hippocampus and amygdala and FAAH V_max values are significantly affected in PFC, hippocampus and cerebellum none of the data support a primary role for FAAH in the circadian regulation of the NAE concentrations. FAAH protein expression is not significantly different among the harvest times in any brain region examined. Concentrations of 2-arachidonoylglycerol are significantly affected by time of harvest in the striatum and cerebellum, but not in other brain regions. Together, these data indicate that the NAEs exhibit diverse patterns of change with time of day that are likely the result of alterations in biosynthesis; and support the hypothesis that AEA is a tonic activator of cannabinoid receptor signaling. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.

PMID:

 

24138639

 

[PubMed – as supplied by publisher]