Selectivity of action of typical and atypical anti-psychotic drugs as antagonists of the behavioral effects of 1-[2,5-dimethoxy-4-iodophenyl]-2-aminopropane (DOI).

Abstract

1. There has been considerable research in the field of schizophrenia over the past few years with emphasis on the discovery of better drugs, particularly those with 5-HT2 antagonist activity. 2. In an effort to enhance identification of such compounds and to further understand the contribution of 5-HT2 activity to the effects of antipsychotic drugs, a series of conventional, atypical and purported antipsychotic compounds were assessed as antagonists of DOI-induced behaviors in rats. 3. DOI (1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride) is an hallucinogen having high affinity and selectivity as an agonist at 5-HT2A/2C receptors. Over a 30-min period after injection, DOI (0.3-10.0 mg/kg; i.p.) produced dose-related behavioral effects including head-and-body shakes, forepaw tapping and skin-jerks. Effects of the antipsychotic drugs and other compounds (30 min pretreatment; i.p.) were examined against a fixed dose of DOI (3.0 mg/kg). 4. In a dose-dependent manner, M100907 (MDL 100,907), risperidone, haloperidol, clozapine, iloperidone, olanzapine, amperozide, remoxipride, ritanserin and the neurotensin agonist NT1 (N alpha MeArg-Lys-Pro-Trp-Tle-Leu) antagonized each of the three behavioral effects of DOI. Drugs attenuating the head-and-body shakes were equally effective in blocking both forepaw tapping and skin-jerks indicating that these behaviors are mediated by similar mechanisms. The following compounds had either inconsistent or no effect on the DOI-induced behaviors: SB 200646A, citalopram, imipramine, fluoxetine, morphine, CP 99994, diazepam, ondansetron and SKF 97541. 5. The data show that antipsychotic agents, as a drug class, effectively block the effects of DOI. These actions are selective, as a series of nine non-antipsychotic and centrally-acting drugs were generally inactive in the procedure.

• Authors: J G Wettstein, M Host, J M Hitchcock
• Journal: Progress in neuro-psychopharmacology & biological psychiatry (Prog Neuropsychopharmacol Biol Psychiatry) Vol. 23 Issue 3 Pg. 533-44 (Apr 1999) ISSN: 0278-5846 [Print] England
• PMID: 10378235 (Publication Type: Journal Article)

Chemical References

• Antipsychotic Agents
• Receptors, Serotonin
• Serotonin Receptor Agonists
• dimethoxy-4-indophenyl-2-aminopropane
• Indophenol
• Dopamine

Topics

• Animals
• Antipsychotic Agents (pharmacology)
• Dopamine (pharmacology)
• Dose-Response Relationship, Drug
• Indophenol (analogs & derivatives, pharmacology)
• Male
• Rats
• Rats, Sprague-Dawley
• Receptors, Serotonin (drug effects, physiology)
• Schizophrenia (drug therapy, physiopathology)
• Serotonin Receptor Agonists (pharmacology)
• Stereotypic Movement Disorder (chemically induced)