Interactions of CB1R and glutamatergic systems may also provide an explanation for the psychotomimetic effects of Δ9-THC. CB1Rs are also expressed in glutamatergic cortical principal neurons [7, 52, 113, 141, 142, 146, 159, 213]. Several studies have reported that cannabinoids reduce glutamatergic synaptic transmission in several brain regions involved in the regulation of gating functions, such as the hippocampus [156], the prefrontal cortex [17], the nucleus accumbens [187], and the amygdala [18].
