A graph shows a spike in abnormal epileptic brain activity. New research suggest the depletion of an inhibitory protein called InSyn1 may be responsible for the brain disease. Photo by Akiyoshi Uezu/Dan Kanak/Scott Soderling
DURHAM, N.C., Sept. 9 (UPI) -- Brain synapses are the gaps between neurons across which messaging signals travel. There are two types, excitatory and inhibitory.
Until recently, researchers thought inhibitory synapses were comparatively unsophisticated, host to a limited number of messaging proteins. But new research revealed 140 proteins, never before observed bridging inhibitory synapses.
"It's like these proteins were locked away in a safe for over 50 years, and we believe that our study has cracked open the safe," senior researcher Scott Soderling, an associate professor of cell biology and neurobiology at Duke University, said in a news release. "And there's a lot of gems."
Scientists used a technique called BioID to identify the elusive proteins. The method relies on a bacterial enzyme to attract and trap proteins congregating near an inhibitory synapse. Researchers used live mice as test subjects in which to trap the protein collections.
The proteins were then recovered from the subjects' brain tissue and identified. Their analysis revealed a surprisingly large list of proteins.
"We both almost fell out of our chairs," Soderling said. "We saw this huge list of these really exciting proteins that no one had ever seen before."
Scientists found several dozen proteins previously linked with brain diseases and substance abuse. They also found two new proteins -- Inhibitory Synapse 1, or InSyn1, and Inhibitory Synapse 2, or InSyn2 -- with no known functions.
Researchers also found proteins associated with epilepsy.
Researchers have previously struggled to identify how the proteins trigger seizures.
"Finding them at the inhibitory synapse really gives us important insights," Soderling said. "The hypothesis now is that these mutations are impairing the ability of neurons to inhibit activity. That's something that we're actively studying."
Researchers published their study of inhibitory synapses in the journal Science.
Soderling and his colleagues now plan to explore the role of inhibitory synapses in the formation and maintenance of long-term memory.