Dopamine from cannabis uses an opiate channel

Experiments have revealed that, in common with other euphoriant drugs, THC selectively activates dopaminergic neurons in the ventral tegmental area. In an electrophysiological study French et al. (1997) reported that low doses of THC increased the firing of these cells. Tanda et al. (1997) used microdialysis probes to show that low doses of THC (0.15 mg/kg intravenously) caused an increased release of dopamine from the shell region of the nucleus accumbens, an effect that is also seen after administration of heroin, cocaine, d‐amphetamine and nicotine. Tanda et al. (1997) found that the increased release of dopamine provoked by THC could be blocked by administration of the µ‐opiate receptor antagonist naloxonazine, suggesting the involvement of an opioid mechanism.