There are three different types of synapse. Specifically, Suzanne’s team were looking at GABAergic synapses. GABAergic synapses are named after gamma-Aminobutyric acid – a chemical called a neurotransmitter that carries signals in the nervous system. GABAergic synapses naturally limit the spread of signals (including epileptic activity).
Suzanne’s team figured out that a protein called Sema4D was an essential building block for this type of synapse. They found that when the protein was removed, brain cells could no longer build GABAergic synapses – the kind that limits epileptic activity. Then one member of the team – Marissa Kuzirian – suggested that they try adding Sema4D to brain cells to see what happened.
The team did not expect the results. Within 30 minutes, dozens of new GABAergic synapses had been created – much, much more quickly than the team could have guessed. They immediately realised how important this might be in treating a condition like epilepsy. Adding the protein to the brain cells of a person with epilepsy may lead to new GABAergic synapses – stopping the spread of seizure activity.
To test their idea, Suzanne’s team used a slice of mammal brain that was treated to create seizure-like conditions in the laboratory. Sema4D was then added to the brain tissue. Within half an hour, the electrical activity in the tissue had reduced significantly – falling from the levels of a seizure and back almost to normal.
In a press release, Suzanne said “We were not intending to study epilepsy, yet we discovered something we didn’t know before. That’s why funding basic research is so important. You never know where the next big, groundbreaking discovery is going to come from.”
Suzanne is careful to point out that this research is in its early stages. Much more must be done to turn their discovery into a treatment for epilepsy in living humans. Their initial findings were published in an onlline edition of The Journal of Neuroscience on 22 May.