Pharmacological inhibition of histamine N-methyltransferase extends wakefulness and suppresses cataplexy in a mouse model of narcolepsy.

Histamine, a neurotransmitter, plays a predominant role in maintaining wakefulness. Furthermore, our previous studies showed that histamine N-methyltransferase (HNMT), a histamine-metabolizing enzyme, is important for regulating brain histamine concentration. However, the effects of pharmacological HNMT inhibition on mouse behavior, including the sleep-wake cycle and cataplexy, in a mouse model of narcolepsy have not yet been investigated.