TRH and Cognitive impairment: The TRH analogue 2-Pyz-L-His (1-alkyl)-L-Pro-NH2, which exhibits high selectivity towards TRH-R2, and is more stable in rat blood plasma than TRH, possesses cognitive-enhancing activity when administered intravenously in the scopolamine-induced cognition impairment mice model, evaluated with the Morris water maze and the passive avoidance tests (Meena et al., 2015).