Effects of chronic, developmental, cannabinoid treatments on endogenous 2-AG levels in zebra finch brain. Brains were rapidly dissected into rostral (Rostral Tel.) and caudal (Caudal Tel.) telencephalon, midbrain and cerebellum. Lipids were extracted, spiked with deuterium-labeled internal standards and subjected to LC-ESI-MS-MS for quantitative analysis of 2-arachidonyl glycerol (2-AG) content. (A): ANOVA indicates a significant relationship between brain region and 2-AG content (p < 0.05). Post-hoc analysis reveals a significant increase in 2-AG content in rostral telencephalon (which contains the song regions lMAN and Area X). Significant decreases in endocannabinoid content within cerebellum were observed following developmental WIN (*p < 0.05). (B): No effect of repeated WIN treatments given during adulthood on 2-AG levels were found.