Cannabis slows down nerve cell degeneration

by Jake Kapsner

Cannabis might help the brain, but don’t fire up the joint just yet.
A recent University study suggests THC, the active ingredient in marijuana, could decrease the spread of nerve cell death that often occurs after a brain injury, epilepsy or stroke.
“My data from cellular observation suggests that THC could help people with traumatic brain injury,” said Stanley Thayer, associate professor of pharmacology.
Thayer emphasized the research needs more examination, including animal tests, before human beings could ever become test subjects.
In the study, published in the October issue of Molecular Pharmacology, researchers infused rat brain cells with a special dye and performed tests to measure the effects of THC on synaptic activity in the brain.
During synaptic activity, nerve cells communicate signals to one another. But following an injury, the synapse is thrown off kilter, sending an aberrant signal that causes other nerve cells to rapidly degenerate, Thayer said.
Cells literally excite themselves to death during this chemical signaling process, called excitotoxicity. And because nerve cells are connected, the degeneration spreads out from the initial site of injury, Thayer said.
Yet the study showed that cannabinoids, the drug group which includes THC, inhibit synaptic activity and could thus be used to decrease nerve cell degeneration.
“Once a neuron’s gone, it’s gone. So anytime you have an intervention that can help retard that destruction, it’s important,” said Dr. Virginia Seybold, University professor of cell biology and neuroanatomy.
For now, the results only apply to a dish of rat brain cells, but Thayer hopes other researchers will further develop the discovery.
“There’s not much one can do to protect neurons from this type of damage. The idea that you can protect nerve cells from this type of damage with drugs is exciting,” he said.
Understanding how THC works in the human brain has historically baffled scientists, and the past few years have seen intense study of the drug, according to the National Institute on Drug Abuse. The institute is a primary sponsor of the University study.
Thayer’s research piggybacks recent studies that found receptors in nerve cells that are specifically tailored to cannabinoids, Seybold said.
The idea that cannabinoids can influence brain cell communication has applications to other areas of the nervous system, like sensory neurons in the skin, Seybold said.
She studies how neurons in the skin respond to painful stimulus like sunburn and how cannabinoids can be used to treat pain.
Dronabinol, a cannabinoid, is now used medicinally to help prevent vomiting and nausea in patients with cancer and HIV, Thayer said.
Yet cannabinoids’ euphoric side effects pose a problem, he said.
Even if THC could effectively impede the nerve cell degeneration that follows brain injury, it still poses the problem of interfering with normal brain stimulation, Thayer asked.
“The fact that people get high tends to pose undesired effects,” he said.
Thayer has studied brain signaling processes at the University for 10 years and began cannabinoid research three years ago.
He said the search for neuro-protective drugs is “a hot new area” in pharmaceutical research, but that he doesn’t support or denounce cannabinoids specifically.
“I’m not pro or con,” he said. “It represents an interesting chemical family that has some useful chemical features,” he said.
“Drugs in my line of work aren’t good or bad. They have some useful properties and they also have some problems,” Thayer said.