Suarez_2011_Neurosci_192_112

1,2-diacylglycerol lipase alpha (DAGLalpha) is responsible for the biosynthesis and release of 2-arachidonoyl-glycerol (2-AG), the most abundant endocannabinoid in the brain. Although its expression has been detected in discrete regions, we showed here an integrated description of the distribution of DAGLalpha mRNA and protein in the rat forebrain using in situ hybridization histochemistry and immunohistochemistry. As novelty, we described the distribution of DAGLalpha protein expression in the olfactory system, the rostral migratory stream, neocortex, septum, thalamus, and hypothalamus. Similar DAGLalpha immunostaining pattern was also found in the brain of wild-type, but not of DAGLalpha knockout mice. Immunohistochemical data were correlated by the identification of DAGLalpha mRNA expression, for instance, in the somata of specific cells in olfactory structures, rostral migratory stream and neocortex, cells in some septal-basal-amygdaloid areas and the medial habenula, and magnocellular cells of the paraventricular hypothalamic nucleus. This widespread neuronal distribution of DAGLalpha is consistent with multiple roles for endocannabinoids in synaptic plasticity, including presynaptic inhibition of neurotransmitter release. We discuss our comparative analysis of the forebrain expression patterns of DAGLalpha and other components of the endocannabinoid signaling system, including the CB(1) receptor, monoacylglyceride lipase (MAGL), and fatty acid amide hydrolase (FAAH), providing some insight into the potential physiological and behavioral roles of this system.