HCRTR2 and Cataplexy: Orexins (also known as hypocretins) are two neuropeptides with conserved structures and functions across mammals1,2; they are necessary for stable wakefulness and sleep–wake cycles, as illustrated by the cataplexy and sleep fragmentation displayed by orexin or orexin type-2 receptor or orexin cell knockout mice3–5, orexin type-2 receptor-deficient dogs6 and orexin-deficient humans7–9.