Tarantula Toxin Sheds Light on Electrical Activity in Neurons and Other Cells

Scientists are using an unusual compound to get a closer look at the electrical activity in neurons and other cells: tarantula toxin. They've combined the toxin with a fluorescent compound to better understand what happens in the interactions between cells.

"Ion channels have been called life's transistors because they act like switches, generating electrical feedback," said Jon Sack, the senior author of the new study, in a news release. "To understand how neural systems or the heart works, we need to know which switches are activated. These probes tell us when certain switches turn on."

In this case, the researchers created a cellular probe that combines tarantula toxin with the fluorescent compound.  The probe binds to a voltage-activated potassium ion channel subtype, lighting up when the channel is turned off and dimming when it is activated. This, in particular, represents the first time researchers have been able to visually observe these electrical signaling proteins turn on without genetic modification.

Voltage-gated channels are proteins that allow specific ions, such as potassium or calcium, to flow in and out of cells. They perform a critical function, generating and electrical current in neurons, muscles and other cells. There are actually many different types of channels, including more than 40 potassium channels. And until now, it's been difficult to differentiate which specific channels were turning on. With the new probe, though, scientists are learning more than ever about these electrical interactions.

In fact, it's likely that this ability to better examine electrical signaling could help researchers map the brain at its most basic levels.

"Understanding the molecular mechanisms of neuronal firing is a fundamental problem in unraveling the complexities of brain function," said Bruce Cohen, one of the researchers.

The findings reveal a bit more about these interactions. Not only that, but they pave the way for future studies.

"The beauty of this is the potential," said Sack. "This is a toehold into a new way of visualizing electrical activity, and there's a huge family of spider toxins that target different ion channels. We've tagged a Ford, we should be able to tag a Chevy."

The findings are published in the journal Proceedings of the National Academy of Sciences.