A new class of compounds, 1-[(1-methyl-1H-imidazol-2-yl)methyl]-4-phenylpiperidines, acts as positive allosteric modulators (PAMs) of the metabotropic glutamate receptor 2 (mGluR2). Structure-activity relationship studies produced potent and selective mGluR2 PAMs with favorable pharmacokinetic properties. The lead compound (+)-17e dose-dependently reduced methamphetamine-induced hyperactivity and mescaline-induced scratching in mice, suggesting potential for treating psychosis.
Psilocybin produces rapid and sustained antidepressant effects in major depressive disorder, but the underlying neurobiological mechanisms are unclear. In mice, psilocybin caused dose-dependent occupancy of the 5-HT₂A receptor in the prefrontal cortex, with an inverted-U dose-response for head twitch behavior peaking between 44% and 62% receptor occupancy. A 1.5 mg/kg dose increased time spent in open areas of the elevated zero maze, indicating reduced anxiety, while 3 mg/kg reduced immobility in the forced swim test, suggesting antidepressant-like effects. Both doses shifted α-tubulin post-translational modifications toward more dynamic microtubules and selectively increased synaptic protein expression in the prefrontal cortex, but not the amygdala. These findings indicate that psilocybin's therapeutic effects may involve dose- and region-specific enhancement of neuronal plasticity, with distinct signatures for anxiolytic-like and antidepressant-like properties.