When we think of spiders our usual reaction is negative, especially towards poisonous spiders. There are more than 40,000 species of spiders identified, of which 99% are poisonous. Fortunately, only a small number of them are dangerous to humans (The Venom Chronicles). However, precisely because of its effectiveness, spider venom has numerous practical uses in medical research. Spider venom has been researched for many years, but the last years have seen technological advances, for instance in mass spectroscopy, but also in genetic engineering and chemical synthesis, which have been of great help to study the possibilities of using spider venom as a research tool as well as in medicine.
Spider venom used to treat cancer and other diseases
Spider venom has long been researched as a potential cure for many diseases. It was found that very low solutions of spider venom could inhibit the proliferation of lung cancer cells. Black widow spider venom has found to contain a peptide, which could potentially be used to treat Alzheimer's disease. In Australia, research is being carried out on the venom of the Funnel Web spider, considered to be one of the most lethal spiders to humans, as a pain medication. The venom of a South American spider is researched as a possible tool to help prevent heart fibrillation, which often leads to death when a person is suffering from a heart dysfunction. The venom of the Brazilian wandering spider (see photo) is studied for a possible remedy against erectile dysfunction. Spider venom is even being studied as a means of limiting stroke damage. How is all this possible?
Spider venom as research tool
Spider venom, just like the venom from snakes and some scorpions, acts very fast and is quite effective because it consists of a number of compounds, which have very specific targets. Spider venom is a cocktail of enzymes, peptides, amino-acids and other molecular substances which are usually very small molecules with a low weight. They target, for instance, (anti) coagulant pathways, ion channels, certain membranes or neurotransmitter receptors.
One way in which toxins work is by targeting specific channels which are called ion channels (an ion is an electrically charged atom or molecule) and which regulate the flow of ions between cells. This process is used for all kinds of communications within the body. Scientists are studying how these channels function, since they are the basic communication channels between cells. But identifying these channels has been a challenge, since there were few specific compounds available to do this. Spider, snake and scorpion venoms (or to be correct, most often their synthetic varieties, as real venom is often difficult to obtain) are now used to identify these channels. They block specific ion channels, thereby making their identification possible.
There are many different types of ion channels in the human body. The main three types of ion channels are calcium channels, potassium channels and sodium channels. Calcium channels are mostly found in muscle tissue, while sodium channels appear to be connected to nerve cells and muscle cells. Potassium channels are thought to be extremely important in the cardiac muscles. Most ion channels are extremely specific, making it possible to develop very specific medicines (references: see below).
Neurotransmitters and blood coagulants
Ion channels are not the only way spider venom works. Another important way is via neurotransmitter receptors. Spider venom targets specific neurotransmitter sites, which may lead to the release of a large amount of neurotransmitters, causing pain, muscle cramping, respiratory problems and a number of other symptoms. Researchers are now looking at toxins that oppose this effect and are trying to find compounds that will block neurotransmitter release. The same holds for blood coagulants. Some spider toxins attack the blood coagulant pathways, causing massive bleeding because the blood will not clot. Spider venom has been shown to contain both coagulant and anti-coagulant. This could be the basis for useful medicines, for instance in cases of haemophilia, where the blood needs to clot and does not,.
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spider venom and ion channel research
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Tamara Croes - Tamara is an environmental consultant and freelance writer and translator. She currently resides in Sweden.
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