Though neurotoxins are often neurologically destructive, their ability to specifically target neural the way of analysis by robert s strichartz pdf is important in the study of nervous systems. Some substances such as nitric oxide and glutamate are in fact essential for proper function of the body and only exert neurotoxic effects at excessive concentrations. Exposure to neurotoxins in society is not new, as civilizations have been exposed to neurologically destructive compounds for thousands of years. As with any highly complex system, however, even small perturbations to its environment can lead to significant functional disruptions.
As a result, the nervous system has a number of mechanisms designed to protect it from internal and external assaults, including the blood brain barrier. As the brain requires nutrient entry and waste removal, it is perfused by blood flow. Blood can carry a number of ingested toxins, however, which would induce significant neuron death if they reach nervous tissue. By being hydrophobic and small, or inhibiting astrocyte function, some compounds including certain neurotoxins are able to penetrate into the brain and induce significant damage. Though clinical neurotoxicology is largely a burgeoning field, extensive inroads have been made in the identification of many environmental neurotoxins leading to the classification of 750 to 1000 known potentially neurotoxic compounds. Examples of improvements include tractable, uniform environments, and the elimination of contaminating effects of systemic metabolism.
In vitro systems, however, have presented problems as it has been difficult to properly replicate the complexities of the nervous system, such as the interactions between supporting astrocytes and neurons in creating the BBB. Due to the significant inaccuracies associated with this process, however, it has been slow in gaining widespread support. Though methods of determining neurotoxicity still require significant development, the identification of deleterious compounds and toxin exposure symptoms has undergone significant improvement. As the nervous system in most organisms is both highly complex and necessary for survival, it has naturally become a target for attack by both predators and prey. As such, neurotoxins provide an effective means by which certain elements of the nervous system may be accurately and efficiently targeted. As neurotoxins are compounds which adversely affect the nervous system, a number of mechanisms through which they function are through the inhibition of neuron cellular processes.
TTX can be fatal if consumed, and has become a common form of poisoning in many countries. The primary mechanism by which TTX is toxic is through the inhibition of sodium channel function, which reduces the functional capacity of neuron communication. Inhibited signaling in tetrodotoxin poisoning. Inhibited signaling response resulting from neuron exposure to tetrodotoxin. This results in an increased effective threshold of required excitatory signals in order to induce an action potential in a postsynaptic neuron.
TTX exposure, there is currently no antitoxin. Additionally, through chronic TEA administration, muscular atrophy would be induced. It is this capability to inhibit potassium flux in neurons that has made TEA one of the most important tools in neuroscience. It has been hypothesized that the ability for TEA to inhibit potassium channels is derived from its similar space-filling structure to potassium ions. Ingestion of lethal volumes of Cltx results in paralysis through this ion channel disruption. Similar to botulinum toxin, Cltx has been shown to possess significant therapeutic value. Conotoxins represent a category of poisons produced by the marine cone snail, and are capable of inhibiting the activity of a number of ion channels such as calcium, sodium, or potassium channels.