CBD blocks adenosine uptake by inhibiting the adenosine transporter, leading to an accumulation of adenosine which causes a sedative effect.

“the most convincing thing that I've seen that CBD binds to is the work that CC Hillard has done looking at its ability to um essentially block adenosine uptake and so it can inhibit the adenosine transporter so it causes people feel more alert no because you're getting more adenosine so you get an accumulation it blocks the adeny transport mechanism I see so you get an accumulation of adenosine which is more sedative um and that I mean in the pnas paper that um CC's lab had from 2006 they showed that that also mediated it was the adenosine I think 2A receptor that drove the um anti-inflammatory effects of CBD”