UC San Diego Biologists Receive $1 Million W.M. Keck Foundation Grant
San Diego, July 23, 2013 -- Biologists at UC San Diego who recently discovered that the brain cells of adult rats can alter the neurotransmitters they secrete in response to changes in the amount of daylight have been awarded a $1-million research grant from the W.M. Keck Foundation. Their mission: to study this neurotransmitter switching mechanism in greater detail so neuroscientists might one day be able to develop new treatments for human brain disorders such as Parkinson’s.
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Their discovery that the adult mammalian brain is much more malleable than was once thought has opened a new area of inquiry for examining brain disorders, particularly the behavioral changes in our brain linked to light reception, and for new ways to treat disorders such as Parkinson’s, caused by the death of dopamine-generating cells in the brain.
The neurobiologists reported in the April 26 issue of Science that rats exposed for one week to 19 hours of darkness and five hours of light every day had more nerve cells making dopamine, which made them less stressed and anxious when measured using standardized behavioral tests. Meanwhile, rats exposed for a week with the reverse—19 hours of light and five hours of darkness—had more neurons synthesizing the neurotransmitter somatostatin, making them more stressed and anxious.
Humans who live in high latitudes in the Northern Hemisphere during the winter often develop signs of depression and stress—so-called “winter blues” or Seasonal Affective Disorder—caused by low light levels, which can be treated by increasing their exposure to full-spectrum light. Spitzer’s and Dulcis’s discovery provides an explanation for what happens in our brains when this happens and why the situation in rats can be so easily reversed.
“We’re diurnal and rats are nocturnal,” said Dulcis. “So for a rat, it’s the longer days that produce stress, while for us it’s the longer nights that create stress.”
In their study, the scientists plan to collaborate with researchers at the UC San Diego medical school using PET scanning technology to pinpoint the areas in the rat brain where the changes in neurotransmitter activity is occurring. They also hope eventually to enlist the help of engineers and other scientists at the university’s newly established Center for Brain Activity Mapping (CBAM), in the Kavli Institute for Brain and Mind, to develop tools that can precisely measure the amounts of neurotransmitters being secreted from each neuron over time. Spitzer is also affiliated with the Qualcomm Institute, the UC San Diego division of Calit2, a founding partner in CBAM.
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Kim McDonald, 858-534-7572, kmcdonald@ucsd.edu