AMPA ([RS]-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors belong to the subclass of gluta-
mate receptors known as ionotropic or ion channel receptors (iGluRs), in addition to the kainic acid (KA), and N-methyl-D-aspartate (NMDA) families. AMPA receptors were originally called quisqualate receptors because of their affinity for quisqualic acid, derived from the Cambodian quisquala tree. However, the seaweed toxin kainic acid (KA) was also found to activate these receptors to a lesser degree. Further studies then found that [3H]AMPA distinguished this group of receptors more clearly from [3H]KA binding sites in brain tissue. Glutamic acid is the major endogenous ligand for the iGluRs, although additional so-called EAAs (excitatory amino acids), named for their generation of excitatory postsynaptic potentials (EPSPs), are also present in the brain, including L-aspartate, quinolinate, and homocysteate. The other current major subclass of receptors activated by glutamate, the metabotropic type (mGluRs), are guanine nucleotide binding protein (G-protein)-coupled and are voltage-gated as opposed to ion-gated. The AMPA receptor/channel complex and the KA and NMDA iGluR channel types are the main mediators of excitatory neurotransmission in the brain. They also have many roles outside the central nervous system.
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With all the stresses and strains of modern living, panic attacks are become a common problem for many people. Panic attacks occur when the pressure we are living under starts to creep up and overwhelm us. Often it's a result of running on the treadmill of life and forgetting to watch the signs and symptoms of the effects of excessive stress on our bodies. Thankfully panic attacks are very treatable. Often it is just a matter of learning to recognize the symptoms and learn simple but effective techniques that help you release yourself from the crippling effects a panic attack can bring.