Researchers have shed light on why stress increases seizure frequency for patients with epilepsy.
Epilepsy is a neurological disorder characterized by recurrent seizures, which are sudden surges of electrical activity in the brain.
According to the Epilepsy Foundation, around 1.3-2.8 million people in the United States have epilepsy. Each year, around 48 in every 100,000 Americans develop the condition.
Stress and anxiety are well-established triggers for seizures among people with epilepsy, and studies have shown that reducing stress may lower seizure risk for those with the condition.
While neurologists recommend that patients with epilepsy avoid stressful situations as a way of avoiding stress-induced seizures, it is not always possible to do so, highlighting the need for a therapeutic alternative.
However, because scientists have been unclear about how stress causes seizures, such a treatment has proven difficult to find.
Now, Michael O. Poulter, Ph.D., of the University of Western Ontario in Canada, and colleagues believe they may have moved a step closer to fulfilling this need.
Stress-induced seizures caused by increased activity in piriform cortex
For their study, the researchers focused on analyzing the activity of corticotropin-releasing factor (CRF) in the brains of rats with and without epilepsy.
CRF is a neurotransmitter - a chemical that enables communication between nerve cells - that regulates the behavioral response to stress.
The researchers assessed how CRF affected the piriform cortex of the rodents, which is a region of the brain in which seizures are known to occur among humans with epilepsy.
Among rats without epilepsy, the researchers found that CRF reduced activity in the piriform cortex of the brain. Among rats with epilepsy, however, they found CRF did the opposite, increasing activity in the piriform cortex.
"When we used CRF on the epileptic brain, the polarity of the effect flipped; it went from inhibiting the piriform cortex to exciting it," explains Poulter. "At that point we became excited, and decided to explore exactly why this was happening."
On further investigation, the team found that CRF altered neuronal signaling in the brains of rats with epilepsy.
Specifically, they found that CRF activated a protein called regulator of G protein signaling protein type 2 (RGS2), which changed communication between nerve cells in the piriform cortex to increase the occurrence of seizures.
The researchers say their findings suggest it may be possible to prevent stress-induced seizures in patients with epilepsy by blocking CRF.
"We are very excited about this possibility for treating epilepsy patients."
Michael O. Poulter, Ph.D.
Furthermore, the researchers say their findings may have implications for other neurological disorders, such as depression and schizophrenia; these conditions might trigger neurochemical processes that increase severity of symptoms.