Researchers at Montréal's McGill University have just made an important contribution to the growing body of knowledge on how cannabinoids affect vision. In their most recent test, Canadian scientists studied how the eyes of tadpoles reacted to cannabinoid exposure. Interestingly, they found that cannabinoids actually improve night vision by increasing the speed of neurotransmitters.
Cannabinoids are the active ingredient in substances like marijuana. But cannabinoids are also naturally occurring chemical compounds in our bodies. Artificially produced cannabinoids are called exogenous, while those produced inside our bodies are called endogenous.
The result of this test comes as a bit of a surprise even to the study's researchers, most of whom came from the Montréal Neurological Institute. Indeed, many researchers admitted that they didn't believe their own results until they tested these tadpoles under a wide variety of circumstances. It had been assumed for many years that cannabinoids actually reduce the speed of neurotransmission. The findings from this study, however, suggest that that hypothesis may have been misguided. Every time the scientists exposed tadpoles to cannabinoids, the tadpoles always experienced a dramatic increase in the rate at which retinal ganglion cells sent visual information to the brain.
For the scientific community, this result has been important for understanding how a certain cannabinoid receptor, called CB1R, works in the body. Researchers note that CB1R's job is to suppress chloride transport into retinal ganglion cells. By activating these receptors with the introduction of cannabinoids, researchers found that chloride was greatly reduced. More research has to be done, but this is a promising finding for understanding how cannabinoid receptors work in our bodies.
The increased rate of neurotransmission has interesting implications for night vision. This is the first study that shows the positive effect cannabinoids can have on visual perception at night in vertebrates. Before this study, there was only anecdotal evidence from a few Jamaican and Moroccan fisherman who said they routinely used cannabis to help them see at nighttime.
Medical marijuana has been a major issue across the Western world, and more people than ever before are taking marijuana for various conditions. In some countries and states, marijuana is also being legalized for recreational use. The more research on the positive and negative effects of this substance on our bodies will become vitally important as the decades wear on.
Researchers at McGill are excited to build upon this study and take a look at how the eyes of mice react to cannabinoids in the near future. If the findings are consistent with their tadpole research, they hope to be able to apply these findings to human subjects.