Pitolisant Inhibits Alcohol Drinking and Improves Withdrawal Negative Affect Through Lateral Habenula Histaminergic Signaling in Mice.

BACKGROUND

Alcohol use disorder (AUD) is a chronic condition marked by compulsive drinking and withdrawal-related negative affect. Histamine (HA) signaling, particularly via the histamine H3 receptor (H3R), may modulate alcohol-related behaviors. We investigated the effects of pitolisant, an FDA-approved H3R antagonist, on ethanol (EtOH)-related behaviors in mice.

METHOD: Adult male C57BL/6J mice underwent acute or chronic (2 or > 8 weeks) intermittent alcohol exposure. Pitolisant pretreatment was administered, and then pharmacological behavior, histologic, and molecular assays were conducted.

RESULT: Pitolisant administration reduced acute EtOH-induced locomotor activation, conditioned place preference, and sedative effects, and also curtailed EtOH intake. It alleviated anxiety and depression-like behavior during 24-h withdrawal (Post-EtOH). Mechanistically, the Post-EtOH condition was featured by complicated brain cFos expression mapping, including elevated cFos, [HA] and [glutamine]/[glutamate] ratio in the lateral habenula (LHb). However, systemic pitolisant treatment significantly increased [norepinephrine]/[normetanephrine] ratio, and restored the diminished phosphorylated CREB and BDNF levels in the LHb. Intra-LHb H2R antagonist cimetidine infusion partly blocked the pitolisant therapeutic effect on alcohol-related behavior.

CONCLUSION

These findings highlight the HAergic system as a critical regulator of alcohol-related behaviors. The LHb HA signaling and norepinephrine neurotransmission might underlie pitolisant's potential novel therapeutic strategy for AUD.