Vanderbilt University researchers discovered a possible reason why people cite anxiety as a reason they use marijuana — the brain absorbs the drug through the same receptors that regulate fight-or-flight responses.
The study, published in March issue of Neuron medical journal, found the nerve cells in the amygdala's central nucleus that make and release their own naturally occuring molecules regulating mood and appetite, among other feelings.
A National Institutes of Health grant funded the study, lead by Dr. Sachin Patel, Vanderbilt professor of psychiatry and of molecular physiology and biophysics.
As more states approve recreational and medical marijuana, studies into its effects on the brain — particularly in teens whose brains are still developing — become relevant to a growing number of Americans. Tennessee's medical marijuana bill, the Koozer-Kuhn Medical Cannabis Act, could allow prescribing the drug for anxiety under the heading of "any other medical condition or its treatment as certified or prescribed by practitioners and approved by the health department."
It's on the House's Health Subcommittee calendar for Tuesday. Its companion bill is stalled in the state Senate.
The researchers used antibodies and electron microscopes to find and label receptors in mice. They didn't use marijuana or its high-causing compounds.
But while marijuana's external cannabinoids can reduce anxiety, previous Vanderbilt research showed, overuse damages the receptors, increasing anxiety and potentially leading to a cycle of addiction.
The research team included scientists from Hokkaido University in Sapporo, Japan, the Hungarian Academy of Sciences in Budapest, and Indiana University in Bloomington.
Reach Heidi Hall at email@example.com or on Twitter @HeidiHallTN.