NOV 01, 2020 4:17 AM PST

A Better View of the Mechanisms Underlying Night Vision

WRITTEN BY: Carmen Leitch

When light levels are low, the rod cells of our eyes (specifically, the retina) go to work to help us see. While some of the specific biochemical pathways in rods are known, researchers have now learned more about a novel one. This work, which was reported in the Proceedings of the National Academy of Sciences (PNAS), involves a molecule called protein kinase A (PKA), a protein with a variety of important biological functions. The study authors engineered a mouse model in which a fluorescent signal changes when PKA is activated.

"PKA is found in many cells and is involved in a wide variety of biological processes. It's natural that researchers would find a way to observe its activities," noted the first author of the study Shinya Sato of the University of Kyoto Graduate School of Biostudies. "PKAchu mice were developed in 2012 -- 'chu' being Japanese for 'squeak'-- to allow us to closely monitor how PKA acts during specific biological processes. I decided to apply this to my work in retina biology."

The researchers also devised a method for capturing high-resolution images of live retinal tissue at high magnification. Combined with the mouse model, they could study how light stimulation altered PKA in the retina; they expected that light exposure would deactivate PKA. However, they were surprised to see the opposite effect.

"We started with a six-second illumination of the tissue. Incredibly, this activated PKA in the selected area for nearly fifteen minutes," revealed Sato. "We then did a ten-minute illumination, during which PKA was inactive. But when the lights were turned off, PKA kicked into gear. It was as if the darkness had activated it."

An analysis of individual cells showed that PKA was only activated in rod cells when the lights were turned off. Rod cells are crucial to night vision. Sato suggested that this may be a way for the eyes to boost their sensitivity to light in low light conditions, enhancing night vision; this activation of PKA seems to only happen in rod cells.

"We have not only uncovered many interesting aspects of retinal cells, but the further utility of PKAchu mice as well. We are excited to uncover the mechanisms and purpose behind these new findings, and perhaps illuminate our understanding of conditions such as night blindness," added the senior author of the study, Michiyuki Matsuda.

Sources: AAAS/Eurekalert! Via Kyoto University, PNAS

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
AUG 23, 2020
Cardiology
Gaining Insight Into a Mysterious Network of Fibers in the Heart
AUG 23, 2020
Gaining Insight Into a Mysterious Network of Fibers in the Heart
Leonardo da Vinci knew about a mesh, fibrous network surrounding the heart, and after hundreds of years, scientists are ...
AUG 27, 2020
Clinical & Molecular DX
Genetic Tool Predicts Breast Cancer Risk in Women of Asian Ancestry
AUG 27, 2020
Genetic Tool Predicts Breast Cancer Risk in Women of Asian Ancestry
  Many diseases such as breast cancer have both a strong genetic component, coupled with a variety of environmental ...
AUG 27, 2020
Genetics & Genomics
Understanding How Animals Make Seasonal Adaptations
AUG 27, 2020
Understanding How Animals Make Seasonal Adaptations
Some animals don't need a new wardrobe to change with the seasons, and scientists have now learned more about how they d ...
NOV 09, 2020
Genetics & Genomics
Potential Problems with Liquid Biopsies
NOV 09, 2020
Potential Problems with Liquid Biopsies
Liquid biopsies are tests that look for biomarkers in the blood, which can help inform the treatment of cancer. The tool ...
NOV 12, 2020
Genetics & Genomics
Liposomes Potentially Safer Alternative to Viruses for CRISPR Delivery
NOV 12, 2020
Liposomes Potentially Safer Alternative to Viruses for CRISPR Delivery
To repair disease-causing errors in the genome, gene editing reagents like those used in CRISPR-Cas9 first have to reach ...
NOV 22, 2020
Genetics & Genomics
Many Kids with Inherited High Cholesterol Don't Get the Treatment They Need
NOV 22, 2020
Many Kids with Inherited High Cholesterol Don't Get the Treatment They Need
Our bodies need cholesterol for certain crucial functions; it's a vital component of cell walls, for example. But there ...
Loading Comments...