Characteristics of behavioral abnormalities induced by a psychedelic substance 2,5-dimethoxy-4-iodoamphetamine in mice

Abstract

For basic research towards regulation of psychedelics, it is important to examine in detail the behavioral patterns of laboratory animals by one of the typical psychedelic substance 2,5-dimethoxy-4-iodoamphetamine (also known as DOI). It has been well known that DOI induces a head-twitch response in rodents. To re-evaluate the behavioral characteristics, we investigated the effects of DOI on behaviors by observers unaware of treatments. Administration of DOI (0.1, 0.5, 1.0 and 2.0 mg/kg, s,c,) or saline vehicle induced increases in preening (“face-washing behavior”), hindlimb scratching, and prone position, but not head-twitch, in dose-dependent fashions. There was a positive correlation between preening and prone position (r² = 0.5988). Preening and hindlimb scratching behaviors occurred frequently in 10 to 15 minutes after the DOI injection, while the prone position reached a plateau level 20 minutes after dosing, suggesting that the behavior of washing the face and scratching by the hind limbs could be observed for up to 20 minutes after DOI administration, and it is thought that the behavior was replaced by the prone position after that. Supported by Ministry of Health, Labor and Welfare Grants-in-Aid for Scientific Research (22KC1005).