The effects of lysergic acid diethylamide and mescaline-derived hallucinogens on sensory-integrative function: tactile startle.
Mark A. Geyer, Lyle R. Petersen, Gary J. Rose, D. Horwitt, Roger K. Light, Lynne M. Adams, John A. Zook, Richard L. Hawkins, Arnold J. Mandell
Journal of Pharmacology and Experimental Therapeutics December 1, 1978 DOI: 10.1016/s0022-3565(25)31486-2 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | Male Sprague-Dawley rats |
| Interventions | LSD N N-dimethyltryptamine psilocin mescaline 2 5-dimethoxy-4-methylamphetamine apomorphine clonidine amphetamine chlorimipramine scopolamine methysergide |
| Topics | LSD Mescaline Psilocybin |
| Keywords | Hallucinogen Habituation Apomorphine Moro reflex Startle response Prepulse inhibition Startle reaction Amphetamine Pharmacology |
| Citations | 69 |
| Key findings | Phenylethylamine-derived hallucinogens increased tactile startle responding, while indoleamine hallucinogens did not; LSD impaired habituation of the startle response. |
Abstract
Tactile startle responding by male Sprague-Dawley rats given 60 presentations of air-puff stimuli (37.5 psi) was measured after the intraperitoneal administration of graded doses of hallucinogens and other psychoactive drugs. Among the drugs tested were the indoleamine-derived compounds, lysergic acid diethylamide (LSD), N,N-dimethyltryptamine and psilocin, and the phenylethylamine-derived compounds, mescaline, 2,5-dimethoxy-4-methylamphetamine and a series of active and inactive congeners of 2,5-dimethoxy-4-methylamphetamine. All of the active phenylethylamines increased startle response magnitudes throughout the test session. This pattern of augmented startle suggests that these drugs increase reactivity. However, none of the indoleamine hallucinogens increased startle responding. Of the nonhallucinogenic drugs tested, only apomorphine increased startle responding, while clonidine significantly decreased it, and amphetamine, chlorimipramine, scopolamine and methysergide had no effect. In additional studies with LSD, it was found that LSD increased the response to only the first stimulus when more intense air-puffs were used (50 psi). Furthermore, when the number of stimuli was increased from 60 to 240 (1 hr) so that appreciable habituation was evident in controls, LSD impaired this habituation. Whereas the response magnitudes of the control group decreased by 70% across the session, the responses of LSD-treated rats decreased by only 32%. These results suggest that LSD and phenylethylamine-derived hallucinogens may differ in their effects on tactile startle responding.