Cannabinoid Receptors Affect How Your Eyes “See”

Culturally, cannabis is known as a substance that heightens the senses; musicians and concert-goers often use cannabis to increase sensitivity to music, and anyone who has experienced “the munchies” can attest to a heightened sense of taste. For a long time we’ve known that our body’s own endocannabinoid system plays a significant role in eyesight. This phenomenon is less discussed, but none-the-less very real, with cannabinoid receptor agonists (like cannabis) and antagonists (like Rimonabant) both causing changes in eyesight. In fact, injections of antagonists into the eye have been observed to lead to unstable and incorrect retinofugal projection, which is essentially the connection between the optic nerve and the brain. Clearly cannabinoid receptors play an essential role in vision. Of course, this is not very surprising to researchers who understand the layout of the endocannabinoid system. Type 1 cannabinoid receptors (CB1 receptors) are “highly expressed in many structures involved in the processing of visual information”, such as the retina, superior colliculus, lateral geniculate nucleus, and most importantly, the primary visual cortex. To date, most studies involving the endocannabinoid system and eyesight occur during development phases rather than adult organisms. As a result, researchers from the University of Montreal created a new study to establish the differences in vision between adult mice with cannabinoid receptors and those without (specifically CB1 receptors). To create adult mice without CB1 receptors, researchers deleted the CB1 gene from the mouse DNA before birth. This procedure is known as creating “knockout” mice. In this particular study,…