Effects of acute cannabis use and short-term deprivation on plasma prolactin and dopamine-beta-hydroxylase in long-term users.

Six long-term cannabis users (10 - 44 years of use) were studied for four days during which cannabis smoking was followed by three days deprivation and smoking on the fourth day. Blood samples were taken at - 30, + 30 and + 120 minutes from each smoking and once in every deprivation day. Pulse rate and blood pressure were measured before each blood sample. Prolactin and dopamine-beta-hydroxylase activity were estimated in plasma. On the third deprivation day, both prolactin and dopamine-beta-hydroxylase were significantly elevated compared to the pre-smoking values, but returned to them after the second cannabis use. The mean arterial pressure followed the same course. The data suggest that cannabis use in man reduces noradrenergic and enhances dopaminergic activity, while deprivation has the opposite effect, possibly through presynaptic receptor mechanisms.