Psilocybin, the active psychedelic compound in magic mushrooms, has some curious effects on the human brain. There’s the apparent , in fact – hallucinations – but of accelerating interest to scientists is its potential effectiveness as an antidepressant.
A recent trial showed that psilocybin was even as effective at managing depression because the most ordinarily prescribed sort of antidepressant drug, selective serotonin reuptake inhibitors (SSRIs). There are hints that psychedelics can induce neural adaptations, yet what psilocybin actually does to the brain and how long it works last isn’t exactly clear.
Researchers have now investigated this in mice, and find out compound triggered an instantaneous , long-lasting increase in neuronal connections after just one dose. it is a finding that would help explain psilocybin’s antidepressant effects, accord. To the team.
“We not only saw a 10% increase within the number of neuronal connections, but also they were on the average about 10% larger, therefore the connections were stronger also ,” said neuroscientist Alex Kwan of Yale University .
Depression is assumed to often be linked to the neurotransmitter serotonin, a hormone that helps transmit signals between regions of the brain. The action of psilocybin (and other serotonergic psychedelics, like ayahuasca & mescaline) is additionally strongly tied to serotonin. This has led scientists to explore their potential as antidepressants – and, fascinatingly, they seem to be quite effective.
Given that SSRIs often have unpleasant side-effects, psychedelics could open up new pathways for treating depression. But not until we understand exactly what these compounds do to the mammalian brain.
They divided a population of mice into 3 groups. One was dosed with nothing but saline, as control group. A 2nd, positive control group was dosed with the anesthetic ketamine, another drug found to possess surprising antidepressant benefits.
The final group was, obviously, dosed with psilocybin. The researchers then used a laser-scanning microscope to trace brain changes altogether 3 groups over several days, then followed up after a month.
Compared to the controls, the psilocybin group had a pronounced increase in sort of neural structure called dendritic spines. These are small protrusions which will be found on the dendrites of the neuron, and that they play a key role within the transmission of electrical signals within the brain & synaptic plasticity.
It’s normal to possess some turnover in dendritic spines, but conditions like long-term stress & depression can see dendritic spine atrophy and a decrease in dendritic spine density.
The effect of psilocybin on the dendritic spines in mice was striking. Compared to the saline control group, a rise in dendritic spine density & size was detectable within 24 hours of receiving one dose, and persisted over subsequent few days. 7 days after the dose, around half the new spines were still there. At 34 days, around a 3rd of the new spines persisted.
The distribution of the new dendritic spines was interesting, too. Some dendrites retained all the new spines that they had grown, while others lost them completely. It’s unclear what this meant at this point , though.
To further investigate the result, the researchers dosed a 2nd group of mice, then sacrificed them 24 hours later and dissected their brains to count the dendritic spines. This affirmed the power of psilocybin to grow new spines in mouse brains.
Finally, when it involves behavioral effects, the psilocybin group of mice seemed better ready to deal with stress. When placed in stressful situation – mild electrical shocks administered to the foot – the experimental group displayed greater inclination & ability to escape , & increased neurotransmitter activity, the researchers found.
The effect was almost like that of ketamine on dendritic spine density, which suggests that rapid neuronal structural remodeling could be key to drugs that have rapid antidepressant effects, like ketamine & serotonergic psychedelics.
How compounds that act differently on the brain have an equivalent effect, is unclear for now and warrants further investigation, the researchers said.
Nevertheless, the result’s a promising one.
“It was a true surprise to ascertain such enduring changes from only one dose of psilocybin,” Kwan said. “These new connections could also be the structural changes the brain uses to store new experiences.”
The research has been published in Neuron.