Cell
April 28, 2021
Chunyang Dong, Calvin Ly, Lee E. Dunlap et al.
207 citations
A genetically encoded fluorescent sensor called psychLight, based on the 5-HT2A receptor structure, detects behaviorally relevant serotonin release and correctly predicts whether structurally similar 5-HT2AR ligands will cause hallucinogenic behavioral effects. Using psychLight, a non-hallucinogenic psychedelic analog was identified that produced rapid-onset and long-lasting antidepressant-like effects after a single administration. The sensor enables in vivo detection of serotonin dynamics, early identification of designer drugs of abuse, and development of non-hallucinogenic therapeutics targeting the 5-HT2AR.
Cell
May 11, 2023
Isha Singh, Anubha Seth, Christian B. Billesbølle et al.
97 citations
Docking over 200 million small molecules against the inward-open state of the serotonin transporter (SERT) identified two potent, low-nanomolar inhibitors that stabilize an outward-closed conformation. These compounds showed little activity against common off-targets, and a cryo-EM structure confirmed the predicted binding geometry. In mouse behavioral assays, both compounds exhibited anxiolytic- and anti-depressant-like activity, with potencies up to 200-fold greater than fluoxetine (Prozac), and one substantially reversed morphine withdrawal effects. The work suggests a promising path toward new treatments for depression, anxiety, and addiction with improved safety.
Scientific Reports
September 5, 2021
Ramona M. Rodriguiz, Vineet Nadkarni, Christopher R. Means et al.
92 citations
Lysergic acid diethylamide (LSD) produces psychedelic effects through the 5-HT2A serotonin receptor, which activates both Gq and β-arrestin signaling pathways. Using mice lacking either β-arrestin1 or β-arrestin2, researchers found that LSD stimulated motor activities and psychedelic-like behaviors—including head twitches, grooming, retrograde walking, and nose-poking—in normal mice and those missing β-arrestin1, but not in mice missing β-arrestin2. The 5-HT2A antagonist MDL100907 blocked these effects. LSD also disrupted prepulse inhibition in normal and β-arrestin1-knockout mice, but not in β-arrestin2-knockouts. These findings indicate that LSD's psychedelic actions require β-arrestin2 signaling.
Biochemistry
July 28, 2009
Feng Yan, Ruslan V Bikbulatov, Viorel Mocanu et al.
81 citations
Salvinorin A, the most potent naturally occurring hallucinogen, targets the kappa-opioid receptor (KOR). Researchers designed and synthesized novel irreversible salvinorin A-derived ligands, RB-64 and RB-48, as active state probes of KOR. Based on molecular modeling, they targeted cysteine residue C315(7.38) for covalent binding. Both compounds were extraordinarily potent and selective KOR agonists in vitro and in vivo. RB-64 showed wash-resistant inhibition of binding requiring a free cysteine near the binding pocket. Mass spectrometry confirmed C315(7.38) as the anchoring residue and suggested a biochemical mechanism for covalent binding. These findings provide direct evidence of a free cysteine in the agonist-bound KOR state and insights into salvinorin A's binding and activation mechanism.
Frontiers in Molecular Biosciences
January 1, 2023
Vladimir M Pogorelov, Ramona M. Rodriguiz, Bryan L. Roth et al.
26 citations
Lisuride, a drug that activates the serotonin 2A receptor but preferentially stimulates G protein over β-arrestin signaling, produced few hallucinogenic-like behaviors (head twitches) in mice, unlike LSD. In wild-type and β-arrestin knockout mice, lisuride reduced locomotion and rearing, increased then decreased grooming in βArr2 knockouts, and decreased serotonin syndrome responses especially in βArr2 knockouts. Prepulse inhibition was disrupted only in βArr1 knockouts at 0.5 mg/kg, and this effect was not reversed by a 5-HT2A antagonist but was normalized by clozapine and other drugs. In vesicular monoamine transporter 2 mice, lisuride reduced immobility in the tail suspension test and promoted sucrose preference for up to two days, suggesting antidepressant-like effects without hallucinogenic actions.
bioRxiv (Cold Spring Harbor Laboratory)
September 26, 2023
Yi-Ting Chiu, Wei Wang, Pierre Llorach et al.
15 citations
preprint
Psychedelic drugs such as LSD and psilocybin show promise as treatments for depression, anxiety, PTSD, migraine, and cluster headaches by activating the 5-HT2A receptor (HTR2A). Researchers engineered several new mouse lines to study the role of HTR2A and the neurons that express it. One line allows visualization of the receptor and identification of HTR2A-containing cells, providing a detailed anatomical map. Another line has a humanized version of the receptor, and a third enables targeted genetic manipulation. The mice exhibited expected behavioral responses to psychedelics, confirming their usefulness. Electrophysiology showed that serotonin increases firing of specific pyramidal neurons through HTR2A, consistent with the receptor's location on the cell surface. These tools will help clarify how psychedelics work at molecular, cellular, and behavioral levels.
bioRxiv Preprint Server
June 13, 2022
Isha Singh, Anubha Seth, Christian B. Billesbølle et al.
8 citations
preprint
The serotonin transporter (SERT) adopts three conformations, and most antidepressants target its outward-open state. Ibogaine, which targets the inward-open state, has an unusual antidepressant profile but is cardiotoxic. Computational docking of over 200 million small molecules against the ibogaine-stabilized inward-open SERT identified 36 top compounds; 13 inhibited SERT with potencies from 29 to 5000 nM. Optimization yielded two inhibitors with Ki values as low as 3 nM that stabilized an outward-closed state and showed little off-target activity. A cryo-EM structure confirmed the predicted binding geometry. In mice, both compounds showed anxiolytic and antidepressant activity with potencies up to 200 times greater than fluoxetine.
bioRxiv Preprint Server
February 4, 2021
Ramona M. Rodriguiz, Vineet Nadkarni, Christopher R. Means et al.
7 citations
preprint
Lysergic acid diethylamide (LSD) produces its psychedelic effects through the 5-HT2A serotonin receptor, which activates two signaling pathways: Gq and β-arrestin. Using mice lacking either β-arrestin1 or β-arrestin2, the authors show that LSD's psychedelic-like behaviors—head twitches, retrograde walking, nose poking, and disrupted prepulse inhibition—require β-arrestin2, not β-arrestin1. LSD also affects motor activity and body temperature in a β-arrestin-dependent manner. The 5-HT2A antagonist MDL100907 blocks these effects in wild-type mice, but in β-arrestin1-knockouts, haloperidol is needed to restore prepulse inhibition. These findings indicate that LSD's diverse behavioral actions are mediated through distinct β-arrestin subtypes, with β-arrestin2 necessary for its psychedelic-like effects.
bioRxiv : the preprint server for biology
June 5, 2023
Vladimir M Pogorelov, Ramona M. Rodriguiz, Bryan L. Roth et al.
4 citations
preprint
Lisuride, a drug that activates the serotonin 2A receptor without causing hallucinations, reduced locomotion and rearing in mice but produced a U-shaped pattern of stereotypies. Head twitches and retrograde walking were rare. Grooming decreased in β-arrestin1 knockout mice but showed a biphasic response in β-arrestin2 knockouts. Prepulse inhibition was disrupted by lisuride only in β-arrestin1 knockouts, and this effect was not reversed by a serotonin 2A antagonist but was normalized by a dopamine D2/D3 antagonist in wild-type mice. Lisuride also reduced immobility in the tail suspension test and increased sucrose preference for up to two days, suggesting antidepressant-like effects without hallucinogenic activity.