Effects on Humans of Δ 9 -Tetrahydrocannabinol Administered by Smoking

Abstract
Twelve chronic marijuana users received ▵9-tetrahydrocannabinol by smoking. The magnitude of their pulse increment was highly correlated with their subjective experiences. Three of the 12 subjects subsequently received ▵9-tetrahydrocannabinol labeled with carbon-14; the time course of its concentration in plasma was highly correlated with the pulse increment. Subjective symptoms, however, appeared later and dissipated more slowly.