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Behavioral Tolerance to Lysergic Acid Diethylamide is Associated with Reduced Serotonin-2A Receptor Signaling in Rat Cortex

Paul J Gresch, Randy L Smith, Robert J. Barrett, Elaine Sanders‐bush

Neuropsychopharmacology March 9, 2005 DOI: 10.1038/sj.npp.1300711 (opens in new tab)

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Study at a glance

AI-extracted from the abstract
Characteristics Animal study Peer reviewed
Population Rats
Intervention LSD
Dose 130 microg/kg LSD for chronic treatment; 60 microg/kg for discrimination testing
Duration 5 days of chronic treatment, tested 24 hours after last injection
Topics LSD Serotonin
Keywords Prefrontal cortex Saline Anterior cingulate cortex Hallucinogen Pharmacology Endocrinology Receptor
Citations 62
Key points Chronic LSD treatment produced a 44% reduction in LSD lever selection and reduced 5-HT2A receptor signaling in the medial prefrontal cortex and anterior cingulate cortex.

Abstract

Tolerance is defined as a decrease in responsiveness to a drug after repeated administration. Tolerance to the behavioral effects of hallucinogens occurs in humans and animals. In this study, we used drug discrimination to establish a behavioral model of lysergic acid diethylamide (LSD) tolerance and examined whether tolerance to the stimulus properties of LSD is related to altered serotonin receptor signaling. Rats were trained to discriminate 60 microg/kg LSD from saline in a two-lever drug discrimination paradigm. Two groups of animals were assigned to either chronic saline treatment or chronic LSD treatment. For chronic treatment, rats from each group were injected once per day with either 130 microg/kg LSD or saline for 5 days. Rats were tested for their ability to discriminate either saline or 60 microg/kg LSD, 24 h after the last chronic injection. Rats receiving chronic LSD showed a 44% reduction in LSD lever selection, while rats receiving chronic vehicle showed no change in percent choice on the LSD lever. In another group of rats receiving the identical chronic LSD treatment, LSD-stimulated [35S]GTPgammaS binding, an index of G-protein coupling, was measured in the rat brain by autoradiography. After chronic LSD, a significant reduction in LSD-stimulated [35S]GTPgammaS binding was observed in the medial prefrontal cortex and anterior cingulate cortex. Furthermore, chronic LSD produced a significant reduction in 2,5-dimethoxy-4-iodoamphetamine-stimulated [35S]GTPgammaS binding in medial prefrontal cortex and anterior cingulate cortex, which was blocked by MDL 100907, a selective 5-HT2A receptor antagonist, but not SB206553, a 5-HT2C receptor antagonist, indicating a reduction in 5-HT2A receptor signaling. 125I-LSD binding to 5-HT2A receptors was reduced in cortical regions, demonstrating a reduction in 5-HT2A receptor density. Taken together, these results indicate that adaptive changes in LSD-stimulated serotonin receptor signaling may mediate tolerance to the discriminative stimulus effects of LSD.

Comparable studies

Other preclinical and animal studies on LSD, most cited first.

Study Year Design Participants
Transcriptome Fingerprints Distinguish Hallucinogenic and Nonhallucinogenic 5-Hydroxytryptamine 2A Receptor Agonist Effects in Mouse Somatosensory Cortex Human embryonic kidney 293 cells stably expressing 5-HT2ARs; wild-type and 5-HT2AR... 2003 Experimental study
Evidence for a central 5‐hydroxytryptamine receptor stimulation by lysergic acid diethylamide Rats 1968 Experimental study
Psychedelics, but Not Ketamine, Produce Persistent Antidepressant-like Effects in a Rodent Experimental System for the Study of Depression Rats 2020 Preclinical study
Lysergic acid diethylamide (LSD) promotes social behavior through mTORC1 in the excitatory neurotransmission Male mice 2021 Multidisciplinary experimental study with in vivo electrophysiology, optogenetics, behavioral paradigms, molecular biology, and conditional knockout mice
A non-hallucinogenic LSD analog with therapeutic potential for mood disorders. Mice and cultured rat cortical neurons 2023 Preclinical study

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