Heffter-ZÜrich Center Psilocybin-Serotonin Receptor Research
A recent focus of the Heffter Zürich Research Center has been an examination of serotonin 5-HT2A neuroreceptor dynamics in the human brain following psilocybin, and its potential relevance for the treatment of obsessive-compulsive spectrum disorders (OCSDs), including OCD and eating disorders. The study is being carried out by Dr. Felix Hasler, Ph.D. and Boris B. Quednow, under the direction of Heffter board member Franz X. Vollenweider.
Initial studies involved synthesizing the positron-emitting tracer molecule [18F]-altanserin, which binds to brain serotonin 5-HT2A receptors. Using positron-emission tomography (PET), the location and density of these receptors can then be visualized in the living human brain. The picture on the left is a side view showing the 5-HT2A brain receptors where psilocybin acts. The receptor density is correlated with color, where red/yellow are the highest receptor concentrations.
Administration of psilocybin can completely prevent the binding of the radioactive tracer to this area. Preliminary analysis reveals a strong and consistent decrease (30%) of [18F]-altanserin binding in the psilocybin condition as compared to placebo.
When the actual clinical study of psilocybin in OCSD patients begins, our Zürich group will have the baseline data to show the normal levels of 5-HT2A receptors in the brain and how psilocybin affects them. Those data will be essential to compare with OCSD patients to gain an understanding of how psilocybin could be an effective treatment. These are the first steps toward demonstrating a mechanism for how psilocybin might help patients with OCD, following up on the pilot study we supported at the University of Arizona, above. We now plan to move toward the biologically-related but difficult to treat problem of eating disorders.
In the other major Zürich study, comparing subjects in a meditation state with subjects under the influence of psilocybin, 3-D EEGs showed striking similarities between the two states of consciousness. This result may further explain how psilocybin “awakens” the brain patterns that occur during meditative and spiritual states of consciousness.