For those of you who picked Florida’s Gulf Coast rather than the Atlantic for spring break or vacation, this article will be of little consolation. That is unless you prefer sitting in your room being educated about tortured by a lesson on voltage-gated sodium ion channels. This is unlikely.
But knowledge is knowledge, and the reason you’re not in the 78o water on Longboat Key just happens to be because your voltage-gated sodium ion channels are not fond of neurotoxins produced by Karenia brevis, a type of algae naturally present in the Gulf (1). The algae are what causes the dreaded “red tide,” which is pretty much an annual occurrence. But this one seems like it will be much worse than usual, even though peak season is still months away.
How bad is red tide?
Although swimming in a red tide is usually not dangerous for most people, it can still produce some pretty nasty symptoms, especially irritation in the eyes, nose, throat, and lungs. It can also cause asthma attacks. But those who are on the fence about swimming in the stuff may be turned off by the 13.5 tons of dead fish that washed up on Fort Myers Beach alone (and this is going on up and down the Gulf for hundreds of miles). Fish and other marine wildlife are especially sensitive to brevetoxin (2), a neurotoxic chemical produced by Karenia brevis algae as a defense system. This is hardly unique; many life forms that may be on the menu for something else develop some sort of a defense system to keep them from being devoured. A number of marine animals and microorganisms are especially good at making neurotoxins.
How do they work?
Well, it’s time to dust off Steve and Irving, who briefly went to Fort Lauderdale but upon observing spring break, they decided hell was more pleasant and returned quite early. This means that they will be available for…
There is just about nothing more complicated than electrophysiology, so I’m going to have to make it really simple. If you don’t like it, see Steve and Irving.
Electrical signals are critical for all forms of life that have nerves. Nerves are the wires that carry signals (electric impulses) from the brain to other parts of the body when triggered by a stimulus, such as a painful injury. They are not meant to fire all the time (this is what happens when you’re exposed to Sarin or VX gas). Instead, they transmit signals interrupted by tiny switches called ion channels. Ion channels are designed to open very rapidly and close to start and stop an impulse. The switches control the flow of ions across cell membranes and maintain the correct number and kind of ions (Na+, K+, Ca++, and Cl–) that control whether the cell “fires” or not. It should be intuitively obvious that since ion channels play an essential role in maintaining timing, they are mostly found in the heart and central nervous system, where timing is essential. Brevetoxin screws up (see Figure 2) the movement of sodium ions in and out of cells, which (to put it technically) makes a gigantic mess. The following two figures should illustrate (in crude form) how ion channels work.
Why is brevetoxin a neurotoxin?
Brevetoxin binds to sodium ion channels, preventing the movement of ions in and out of the nerve cell. This stops the cell from functioning properly. (Figure 2)
But it gets worse
What’s worse than trying to take a vacation in poisonous water surrounded by tons of dead fish? Maybe this is:
If that teensy bunch of seaweed above looks disgusting, it is nothing compared to what is out in the Gulf waiting to wash ashore in the Gulf (3). It is called a “seaweed blob.” The name does not do it justice; the damn thing is 5,000 miles long – twice the length of the US. It has already made it to beaches along the Gulf coast, the Florida Keys, and part of the Caribbean and Mexico uninhabitable. Yuck!
What to do?
That’s simple. Pick a different beach. On the East coast
