Highly sensitive in vivo detection of dynamic changes in enkephalins following acute stress.

Enkephalins are opioid peptides that modulate analgesia, reward, and stress. In vivo detection of enkephalins remains difficult due to transient and low endogenous concentrations and inherent sequence similarity. We present an analytical method for Met- and Leu-Enkephalin detection in the mouse Nucleus Accumbens shell after acute stress. This approach increases spatiotemporal resolution, optimizes the detection of Met-Enkephalin through methionine oxidation, and provides insight into the relationship between Met- and Leu-Enkephalin following stress.