The effect of delta-9-tetrahydrocannabinol and cannabidiol on p50 of the oxygen haemoglobin dissociation curve.

Cannabis is one of the most chemically complex plants containing a large number of compounds, among which are cannabinoids; the main biologically active constituents of the plant. Delta-9-tetrahydrocannabinol (THC) is known as the main psychoactive cannabinoid. Studies have shown that the effects of THC can be modulated by cannabidiol (CBD), another major cannabinoid which has several beneficial effects of its own. This study aims to look at the effect of different concentrations of THC and CBD separately and in combination on the release of oxygen from erythrocytes by measuring the p50 of the oxygen haemoglobin dissociation curve. Blood samples were collected from twenty four healthy adult male and female non-smokers. P50 values were measured using the Hemox Analyzer for different concentrations (0, 2.5, 25, 50 and 100 ng/ml) of THC and CBD respectively, as well as with combinations of THC and CBD in 4:1 and 1:1 ratios. The results indicate that there is a decrease in P with increasing concentrations of both THC and CBD separately and in combination. The decrease in P was significant (p < .05) at all concentrations of THC and CBD. The changes observed with increasing concentrations of both THC and CBD suggests that they have an increased affinity for oxygen. This may have implications for individuals who consistently use cannabis.