Here’s a new hope for Retinitis Pigmentosa and Macular Degeneration treatment. Both of these result in the loss of photoreceptor cells in the retina. These cells enable us to convert light into images. A pain medicine that potently activates a receptor vital to a healthy retina assist preserve vision in a model of severe retinal degeneration.
Pain Medicine: (+)-pentazocine
The study shows that the drug (+)-pentazocine enables the survival of cone cells, in an animal model of severe, inherited retinal degeneration. Cone cells are a type of photoreceptor cell that gives us detailed, color vision.
The study model is a mouse with a genetic mutation that prompts rapid loss of rods and cones by day 35 of life. It is a model of severe inherited retinal degeneration like retinitis pigmentosa. The researchers injected the drug into the abdominal cavity. And this was done every other day through day 42 of life. The result were astonishing.
After 42 days
By day 42, when it was expected that vision loss should have happened, several layers of photoreceptor cells were still clearly visible in the treated mice. And to our surprise, many of those cells were cones.
Dr. Sylvia Smith, chair of the Department of Cellular Biology and Anatomy at the Medical College of Georgia at Augusta University, said,
Mice lacking sigma receptor 1 did not benefit from (+)- pentazocine treatment, more evidence of the receptor’s essential role in retinal protection, Smith said. Treated mice also had evidence of reduced oxidative stress.
Previously, her lab reported in 2008 how the same medicine, (+)- pentazocine appeared to help the multilayer retina maintain its well stratified form and function and reduced loss of ganglion cells. These are the nerve cells in the retina that receive information from photoreceptor cells.
Proceedings of the National Academy of Sciences
The research was funded by the National Eye Institute and James and Jean Culver Vision Discovery Institute at Augusta University, which Dr. Sylvia Smith co-directs.