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Vol. LXII, No. 20
October 1, 2010
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Saved By a Whisker
Facial Stimulation Prevents Stroke in Rodents

Can stroking whiskers prevent stroke? Serendipitous finding provokes new line of study.
Can stroking whiskers prevent stroke? Serendipitous finding provokes new line of study.

It may sound more like science fiction than a carefully controlled scientific protocol, but research indicates that stimulating just one facial whisker of a lab rodent for less than 5 minutes, promptly after blockage of a critical brain artery, can prevent impending stroke. If these findings, reported by scientists supported by the National Institute of Neurological Disorders and Stroke, can be replicated in humans using similar means, it could offer an easy-to-deliver treatment for thwarting cerebrovascular disease, the third leading cause of death in the U.S. and the number one cause of long-term disability.

Researchers and other medical experts have long sought ways to prevent or limit brain damage due to stroke, since its effects can be so life-shattering. Stroke occurs when blood flow to the brain is suddenly interrupted or when a cerebral blood vessel bursts, causing critical brain cells to die. More than 780,000 cerebrovascular accidents (CVAs) or strokes occur yearly, according to NINDS, often leaving patients with symptoms such as paralysis, walking difficulties, memory impairment or blindness, along with other physical, behavioral and intellectual maladies. Further, some 25 percent of adults who do recover experience another stroke within 5 years, NINDS reports. More than 137,000 men and women succumb to the brain event annually.

Dr. Ron Frostig, professor of neurobiology and behavior at the University of California at Irvine and his colleagues conducted research using sensory stimulation in lab rodents in which blood flow in one of the brain’s major arteries was entirely cut off.

“What we found, in somewhat of a serendipitous manner, was that when we stroked a facial whisker of a rat for just a few minutes, this signaled a redirection of the blood flow from adjacent cortical arteries directly to the artery that was experimentally blocked,” said Frostig. This result, a resumption of blood flow in a reverse direction within the blood-deprived artery, as seen via non-invasive brain imaging, was demonstrated in 100 percent of rodents tested—including both younger (age 3-4 months) and older (22 months) rats.

As reported in the June 2010 issue of PLoS One, the investigators demonstrated further that timing of the intervention—during a “window of treatment opportunity”— was paramount. More specifically, brain injury was consistently averted when the facial stroking occurred immediately or very shortly (up to 2 hours) after a stroke would have occurred.

“On the other hand, when the identical stimulation was applied after a 3-hour interval, the end results proved worse (in terms of stroke magnitude) than if no treatment at all was applied,” Frostig noted. The timing correlates well with the current clinical approach for treating some stroke patients: giving tissue plasminogen activator, in best instances, within a few hours (less than 3 hours) of the stroke’s occurrence. This theoretically prevents brain tissue death and its sequela.

Can these findings be currently translated to humans? Not yet, says Frostig. He said it’s important to remember that his lab animals are maintained in carefully controlled environments. “But what is exciting is that we’ve learned that the human vascular system that leads blood to the cortex is basically the same for both rodents and humans, so the stimulation concept certainly raises a level of excitement and warrants further investigation.”

He added, “What we know is that a person’s fingers correlate, on a neurological basis, with the whiskers of a rodent, so, theoretically at least, rubbing a person’s fingers could perhaps elicit the same brain-preserving effect.”

What Frostig envisions, if the findings hold true in humans, is a simple way for emergency medical technicians or other first responders to rapidly apply the brain-stimulating procedure to a person who appears to be having a stroke. By so doing, one might be able to treat the victim long before he or she reaches the emergency room.

The researchers point out that their latest protocol applies to the most common type of CVA, an ischemic stroke, blockage of a blood vessel that normally transports oxygen-rich blood into the brain. Additional research by Frostig’s team will see if findings can be reproduced in hemorrhagic stroke, which entails bleeding into or around the brain. NIHRecord Icon

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