Biochemistry
February 7, 2024
Vito F. Palmisano, Claudio Agnorelli, Andrea Fagiolini et al.
5 citations
Classic psychedelics, which resemble serotonin, act on 5-HT2A receptors inside neurons. This computational study used molecular dynamics simulations to examine how 12 tryptamines cross cell membranes. Dimethylation of the amine group and a methoxy group at position 5 increased permeability. Positional substitutions on the indole ring also influenced permeation, while protonation raised the energy barrier at the bilayer center, making molecules highly impermeable. These simulation-based trends can guide future drug design for psychedelics with improved activity.
ChemRxiv
February 7, 2023
Vito F. Palmisano, Claudio Agnorelli, David Erritzøe et al.
1 citation
Classic psychedelics target the 5-HT2A serotonin receptor, but their precise mode of action remains unclear. Computational modeling of the receptor's orthosteric binding pocket for several psychedelics—including serotonin, LSD, DMT, and a photoswitchable analog (AzoDMT)—revealed two nearly equivalent binding poses. LSD and serotonin preferred the canonical crystallized pose, whereas DMT and 4-OH-DMT slightly favored a newly identified pose. The cis form of AzoDMT was the most stable, and its azobenzene domain interacted with the same residue (L229) responsible for LSD's extracellular loop closure. These simulations clarify drug–protein interactions and may aid development of new psychedelic compounds.
ACS Chemical Neuroscience
February 18, 2026
Vito F. Palmisano, Micaela Vidal−sánchez, Juan J. Nogueira
Bulky substitutions on the N-benzyl ring of 25CN-NBx compounds cause a significant shift in the position of W336, a key toggle switch residue in the 5-HT2A receptor. This shift influences receptor activation and is thought to play a crucial role in mediating psychedelic signaling. Potential of mean force calculations along the toggle switch's dihedral angle confirm this result. End-state free energy calculations show that 25CN-NB-2-OH-3-Me and 25CN-NB-2-OH-5-MeO have the highest and lowest affinities, respectively, for the receptor. When W336 adopts its negative dihedral state, it establishes stronger van der Waals interactions with residues F332 and I163, key players in receptor activation. This framework can extend to other G protein-coupled receptors where the toggle switch is central to signal activation.