A recent study has shed light on how the hallucinogenic chemicals LSD and psilocin, the main component of magic mushrooms, attach to brain receptors.
According to the research, psychedelics operate as an antidepressant by attaching to neuroplasticity-promoting protein brain-derived neurotrophic factor (BDNF) receptors. The process through which the connections in the brain change and create new ones is known as neuroplasticity.
The findings, still in the preclinical stages and published in Nature Neuroscience on June 5, also imply that vivid hallucinations, which some psychedelics proponents have claimed to be a crucial component of the healing process, could be distinguished from psychedelics' antidepressant benefits.
In comparison to traditional selective serotonin reuptake inhibitor (SSRI) antidepressants, the substances appear to operate much more quickly and with arguably fewer side effects.
The long hallucinogenic trips the psychedelic medications cause continue to be a significant barrier to their advancement. Many psychedelic medications have attempted to avoid these experiences since doing so would force a psychedelic drug clinic to install pricey in-patient care, making it far more challenging to have these drugs approved for at-home usage.
Fortunately, researchers from the University of Helsinki have now developed a strategy for developing psychedelics without hallucinations by delving deep into the mechanism by which these substances bond to the brain.
The scientists evaluated how the hallucinogenic substances LSD and psilocin bind to a dish's neurons using various biochemical methods. The research team primarily focused on BDNF and its receptor, TrkB, because psychedelics are crucial in promoting neuroplasticity. They discovered that compared to the SSRI fluoxetine and the quickly-acting antidepressant ketamine, LSD binds to TrkB up to 1,000 times more potent.
The binding location that LSD uses to attach to TrkB was further discovered, demonstrating that it only targets the receptor region that spans the neuronal membrane. Utilizing genetically altered neurons with marginally differing TrkB receptors, the researchers could pinpoint precisely which protein regions were essential for binding.
The ability of SSRIs to bind to TrkB was impaired by at least one of these modifications, which changed a single amino acid in the protein's chain, although LSD was unaffected. Other mutations did not exhibit this finding, indicating that the two medicines had slightly related but different binding sites.
The researchers next showed that while psychedelic binding did not raise the concentration of TrkB in neurons, it did, instead, act as a bimolecular lifeboat to help the receptor float closer to the neuron's surface, where it is much simpler to attach to the pro-plasticity protein BDNF.
The researchers also looked at the effects of psychedelic-treated mice on TrkB signaling. It's challenging to study psychological illnesses in mice. Behavioral studies usually focus on how the animals react to stressful conditions rather than interviewing mice to discover their ailments.
Increased antidepressant-like responses were observed in mice administered LSD but not in mice with mutations that altered how the drug binds to TrkB. These latter mice nevertheless exhibited the recognizable "head-twitch" that experts in the area use to recognize serotonin receptor activity. This would imply that TrkB, rather than serotonin 5-HT2A receptors, is the primary mediator of the improvement in mental health caused by psychedelic substances.
The discovery is anticipated to fuel the continuing debate over the efficacy of non-hallucinogenic psychedelics. In-person clinical trials with these drugs will begin this year, signaling the growth of psychedelic psychiatry.
- Nature Neuroscience. Psychedelics promote plasticity by directly binding to BDNF receptor TrkB
- The Centre for Addiction and Mental Health. Hallucinogens