Behavioral and 5-HT antagonist effects of ritanserin: a pure and selective antagonist of LSD discrimination in rat.
Françis C. Colpaert, Theo Meert, C J Niemegeers, Paul A. J. Janssen
Psychopharmacology 1985 DOI: 10.1007/bf00431683 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Preclinical pharmacological study Peer reviewed |
|---|---|
| Population | Rats |
| Interventions | Ritanserin Pirenperone R 56413 Chlordiazepoxide Diazepam LSD 5-HTP |
| Measures | LSD-saline drug discrimination assay, open field test, 5-HT-induced hypothermia, 5-HTP-induced head-twitch response |
| Topics | LSD Serotonin |
| Key points | Ritanserin acts as a pure LSD antagonist in rat drug discrimination, with greater behavioral specificity than pirenperone, and produces open field effects resembling anxiolytic activity that exceed those of pirenperone, R 56413, chlordiazepoxide, and diazepam. The authors report that 5-HT hypothermia and head-twitch experiments do not support ascribing these putative anxiolytic effects simply to action at 5-HT receptors. |
Abstract
The newly synthesized compound and putative 5-HT2 antagonist ritanserin, but not the structurally related compound R 56413, resembles pirenperone in that it acts as a pure antagonist in an LSD-saline drug discrimination assay in the rat. Ritanserin exceeded pirenperone in terms of behavioral specificity; the lowest effective dose of ritanserin in antagonizing LSD was one order of magnitude higher than that of pirenperone, but the compound depressed rate of operant responding only at doses that were about 1000-fold higher than those at which pirenperone was effective. Ritanserin exerted effects in an open field test which were reminiscent of anxiolytic drug activity in the rat; its effects were greater than those of pirenperone, R 56413 and the benzodiazepines chlordiazepoxide and diazepam. The results of experiments on antagonism of 5-HT-induced hypothermia and of the 5-HTP-induced head-twitch response fail to support the possibility that the putative anxiolytic effects of ritanserin in the rat can be ascribed simply to a pharmacologically defined action at 5-HT receptors.
Comparable studies
Other preclinical and animal studies on LSD, most cited first.
Citations in the library
Cited by 17
- Pharmacological profile of ritanserin: A very specific central serotonin S2‐antagonist Drug Development Research 1988
- Behavioral Tolerance to Lysergic Acid Diethylamide is Associated with Reduced Serotonin-2A Receptor Signaling in Rat Cortex Neuropsychopharmacology March 9, 2005
- Characterization of the Discriminative Stimulus Properties Induced by 5‐HT1and 5‐HT2Agonists in Rats Pharmacology & Toxicology February 1, 1989
- The hallucinogen d-lysergic acid diethylamide (d-LSD) induces the immediate-early gene c-Fos in rat forebrain Brain Research December 1, 2002
- Involvement of 5-HT receptor subtypes in the discriminative stimulus properties of mescaline European Journal of Pharmacology 1989
and 12 more in the library
Cites 7
- The Therapeutic Value of Lysergic Acid Diethylamide in Mental Illness Journal of Mental Science April 1, 1954
- On the Use and Abuse of LSD Archives of General Psychiatry March 1, 1968
- Lysergic Acid Diethylamide (LSD-25): I. Physiological and Perceptual Responses The Journal of Psychology 1955
- Lysergic Acid Diethylamide (LSD) and Lisuride: Differentiation of Their Neuropharmacological Actions Science April 30, 1982
- Mescaline‐induced head‐twitches in the rat: An in vivo method to evaluate serotonin S2 antagonists Drug Development Research 1983
and 2 more in the library