Chronic Δ9-tetrahydrocannabinol treatment has dose-dependent effects on open field exploratory behavior and [3H] SR141716A receptor binding in the rat brain.
Life Sciences August 15, 2023 Lily Freeman-Striegel, John Hamilton, Renuka Kannappan et al.
Chronic exposure to Δ9-tetrahydrocannabinol (THC) in adolescent rats alters cannabinoid-1 receptor (CB1R) levels in the brain and affects locomotion in a dose-dependent manner. High-dose THC (2.0 mg/kg daily for 24 days) reduced vertical activity in an open field and decreased CB1R binding in several cortical regions (cingulate, motor, somatosensory, rhinal, and auditory cortices) by 33–50% relative to low-dose THC. Low-dose THC (0.75 mg/kg) increased vertical activity and elevated CB1R binding in the primary motor cortex and hypothalamus by 33% compared to controls. No changes were found in mu-opioid receptor binding. The results indicate that chronic THC dose-dependently affects CB1R levels and motor behavior.