Marijuana can make you see things that aren’t there. But what if it could help you see things in the dark you didn’t realize were there?
That’s what Canadian researchers studying weed’s effect on night vision were trying to figure out when they applied marijuana extract to the eyes of toad tadpoles. Previously, reports that fishermen in the Caribbean that regularly drank weed-laced rum had an uncanny ability to see in the dark, together, with similar findings in hash-smoking Moroccan fishermen suggested that the drug had night vision-enhancing abilities. Researchers from McGill University reported this week in the journal eLife that that hunch is true — at least in toads.
They provide evidence for their hypothesis by proposing a mechanism explaining what actually goes on in the eyes of stoned Xenopus laevis tadpoles. Taking a synthetic cannabinoid — one of a family of molecules that binds to the body’s naturally occurring cannabinoid receptors — and applying it to tadpole eye tissue, the researchers measured the response of retinal cells to light using microelectrodes. As it turns out, they were correct to think that cannabinoids affected their sensitivity: The cells that had been treated with the synthetic weed compound were much more responsive to both bright and dim lights than their untreated counterparts.
Buoyed by the success of this initial experiment, they decided to actually get tadpoles high. A group of the baby toads were treated with the synthetic cannabinoids and dropped into a petri dish spotted with dark dots. Previous research has shown that tadpoles generally avoid dark spots, suggesting that in this experiment, the cannabinoid-treated tadpoles would be better at doing so in the dark. Again, the researchers were right, and their stoned baby toads dodged the dark spots in dim light better than their night-blind, sober counterparts.
Only time will tell whether cannabinoids will have the same effect in humans, but if they do, they could be a huge help to people suffering from degenerative eye diseases like retinitis pigmentosa. For now, the toads remain the only species that have been scientifically shown to benefit from the night vision-boosting effects of cannabinoids, but the success of the research promises not to leave the rest of us in the dark.