Researchers at the University of California in Riverside have discovered a previously unidentified neurotoxin from the American Funnel Web Spider (Agelenopsis aperta), which may help study the causes of several human diseases, among which are hypertension, epilepsy and congestive heart failure. The researchers found that the toxin has a high affinity for two specific types of so-called ion channels.
These channels are found in cell membranes and connect cells to each other. They regulate the flow of ions and play an important role in numerous physiological processes in the body, including the development of diseases. This particular snake toxin has a high affinity for T-type and N-type calcium channels, which are found in different types of tissue all through the body.
When the channels are blocked or are not functioning properly this contributes, among others, to the abovementioned medical conditions. Physiological identification of these channels has been difficult since there were, so far, few specific substances which could be used, among which, interestingly, other spider venom-derived toxins.
The discovery of this new and very efficient spider toxin was therefore an important step forward. The findings could, in the future, be used to develop drugs against these diseases and against pain. The next important step however was to make it readily available.
Since it is difficult to harvest spider venom from spiders in sufficient quantities, the researchers also developed a way to produce a very similar toxin by using a common bacteria species (Escerischia coli) which was genetically modified to produce a recombinant form of the toxin.
It was then tested for efficacy and found to be very similar in its properties to the original. Both versions showed a particularly high efficacy in blocking these specific channels.
This toxin reacts differently from other spider venom-based blocker toxins, according to the researchers, and can therefore be a valuable new research tool. The findings were presented last Wednesday (9th of March) at the 55th annual meeting of the Biophysics Society in Baltimore.
The use of spider venom for ion channel research is not new. It has been known for years that some potent toxins such as can be found in spider and scorpion venom has to target specific ion channels in order to work as fast and effective as they do. Spider venom may well become a very common research tool.