Withdrawal from chronic treatment with (+/-)-DOI causes super-sensitivity to 5-HT2 receptor-induced head-twitch behaviour in mice

Eur J Pharmacol. 1990 Sep 4;186(1):115-8. doi: 10.1016/0014-2999(90)94066-7.


Mice were injected once daily for 13 days with (+/-)-DOI ((+-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane) and the induced head-twitch response (HTR) was scored. On days 2-5 HTR was reduced to less than 50% of day 1, and then returned to control levels by day 13. Challenge doses of (+/-)-DOI administered on days 15, 17 or 19 elicited significantly exaggerated responses. Thus, chronic treatment with (+/-)-DOI may cause an initial down-regulation followed by an up-regulation of 5-HT2 receptor function after cessation of such treatment.

MeSH terms

  • Amphetamines / adverse effects*
  • Animals
  • Behavior, Animal / drug effects*
  • Male
  • Mice
  • Mice, Inbred ICR
  • Receptors, Serotonin / drug effects*
  • Serotonin Antagonists / adverse effects*
  • Substance Withdrawal Syndrome / physiopathology*
  • Time Factors


  • Amphetamines
  • Receptors, Serotonin
  • Serotonin Antagonists
  • 4-iodo-2,5-dimethoxyphenylisopropylamine