Neurotoxins excitatory amino acid

Little is formally known about the toxicity of amanita use. Ibotenic acid is a potent neurotoxin, through excitatory amino acid mechanisms (Steiner et al. 1984 Schwarcz et al. 1984). It has been used extensively in animal research to create discrete neuroanatomical lesions. For example, it has been used to lesion the basal forebrain nuclei to create a putative animal model of Alzheimer s disease (Arbogast and Kozlowski 1988). 

In brain tissue, low concentrations of glutamate and aspartate perform as neurotransmitters, but at high concentration these amino acids act as neurotoxins. Major advances in the excitatory amino acid receptor field have come from the identification, characterization, and cloning of different families of receptors and transporters (Dingledine and McBain, 1999). These receptors and transporters are specialized... 

The red alga Digenea simplex has been used for the treatment of roundworm disease for centuries. Its active principle is kainic acid. The related domoic acid is a constituent of another red alga, Chondria armata, used for the same purpose. These compounds, known as kainoids, are potent neurotoxins and excitatory amino acids. Kainoids are important tools in neurophysiological research. Domoic acids are also produced by diatoms and were responsible for the shellfish poisonings known as amnesic shellfish poisonings that occurred in Canada in 1987. 

Altered release. Tetanus is an infectious disease caused by the bacterium Clostridium tetani. This bacterium produces a neurotoxin active on inhibitory synapses in the spinal cord. Motor neurons, which supply skeletal muscle and cause contraction, have cell bodies that lie in the spinal cord. Under normal circumstances, these motor neurons receive excitatory and inhibitory inputs from various sources. The balance of these inputs results in the appropriate degree of muscle tone or muscle contraction. Tetanus toxin prevents the release of gamma amino butyric acid (GABA), an important neurotransmitter active at these inhibitory synapses. Eliminating inhibitory inputs results in unchecked or unmodulated excitatory input to the motor neurons. The resulting uncontrolled muscle spasms initially occur in the muscles of the jaw, giving rise to the expression lockjaw. The muscle spasms eventually... 

---