Psilocybin: Biphasic dose-response effects on the acoustic startle reflex in the rat
Michael T. Davis, James K. Walters
Pharmacology, Biochemistry, and Behavior April 1, 1977 DOI: 10.1016/0091-3057(77)90180-0 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Sample size | 70 |
| Population | Rats |
| Interventions | psilocybin psilocin |
| Dose | 0.25, 0.50, 0.75, 1.0, 2.0, 4.0, 8.0 mg/kg psilocybin; 0.71 or 5.70 mg/kg psilocin |
| Topics | Psilocybin |
| Keywords | Startle response Moro reflex Hallucinogen Acoustic startle reflex Prepulse inhibition Startle reaction Anesthesia Endocrinology Pharmacology |
| Citations | 26 |
| Key findings | Psilocybin produces a biphasic dose-response effect on the startle reflex, with low doses increasing and high doses decreasing startle amplitude. |
Abstract
The startle reflex was measured in 7 groups of 10 rats each after intraperitoneal injection of saline or 0.25, 0.50, 0.75, 1.0, 2.0, 4.0 or 8.0 mg/kg psilocybin. Low doses (0.75-2.0 mg/kg) increased startle amplitude whereas high doses (4.0-8.0 mg/kg) depressed startle. Selected low (0.71 mg/kg) or high (5.70 mg/kg) doses of psilocin also had a biphasic dose-response effect on startle comparable in magnitude to equimolar doses of psilocybin. This biphasic dose-response relationship of the indole hallucinogen, psilocybin, on startle is consistent with the hypothesis that startle is increased when the firing rates of midbrain raphe neurons are selectively inhibited but is depressed when neurons postsynaptic to raphe cells are also inhibited.
Comparable studies
Other preclinical and animal studies on psilocybin, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocybin induces rapid and persistent growth of dendritic spines in frontal cortex in vivo Mice | 2021 | Observational cohort | |
| Harnessing psilocybin: antidepressant-like behavioral and synaptic actions of psilocybin are independent of 5-HT2R activation in mice Mice | 2021 | Experimental study | |
| Psychedelics reopen the social reward learning critical period Mice | 2023 | Experimental study in mice | |
| Correlation between the potency of hallucinogens in the mouse head-twitch response assay and their behavioral and subjective effects in other species. C57BL/6J mice | 2020 | Experimental study with dose-response experiments | |
| Effects of psilocybin on hippocampal neurogenesis and extinction of trace fear conditioning Mice | 2013 | Experimental study |
Citations in the library
Cited by 20
- Psilocybin – Summary of knowledge and new perspectives European Neuropsychopharmacology December 17, 2013
- Psychedelics, but Not Ketamine, Produce Persistent Antidepressant-like Effects in a Rodent Experimental System for the Study of Depression ACS Chemical Neuroscience March 5, 2020
- The Effects of the Preferential 5-HT2A Agonist Psilocybin on Prepulse Inhibition of Startle in Healthy Human Volunteers Depend on Interstimulus Interval Neuropsychopharmacology February 14, 2007
- Sex differences and serotonergic mechanisms in the behavioural effects of psilocin Behavioural Pharmacology October 13, 2015
- Psilocybin and LSD have no long-lasting effects in an animal model of alcohol relapse Neuropsychopharmacology May 5, 2020
and 15 more in the library
Cites 4
- Lysergic Acid Diethylamide- and Mescaline-Induced Attenuation of the Effect of Punishment in the Rat Science May 21, 1976
- Effects of chlorimipramine and lysergic acid diethylamide on efflux of precursor-formed 3-H-serotonin: correlations with serotonergic impulse flow. Journal of Pharmacology and Experimental Therapeutics June 1, 1975
- Dephosphorylation of Psilocybin to Psilocin by Alkaline Phosphatase Experimental Biology and Medicine 1961
- Opposite effects of intraventricular serotonin and bufotenin on rat startle responses. Pharmacology, Biochemistry, and Behavior 1975