Oral Delta-9-Tetrahydrocannabinol (THC) Increases Parasympathetic Activity and Supraspinal Conditioned Pain Modulation in Chronic Neuropathic Pain Male Patients: A Crossover, Double-Blind, Placebo-Controlled Trial.
CNS Drugs May 1, 2024 Libat Weizman, Haggai Sharon, Lior Dayan et al.
In male patients with chronic radicular neuropathic pain, a single sublingual dose of THC (0.2 mg/kg) shifted autonomic balance toward increased parasympathetic tone, as shown by a reduced low/high frequency heart rate variability ratio, and improved the body's ability to inhibit pain, measured by conditioned pain modulation. These changes correlated with increased functional connectivity between brainstem and prefrontal cortex regions, suggesting THC exerts top-down regulatory effects that may normalize multiple aspects of supraspinal pain dysregulation.