Neurotransmitters glutamate receptors, types

Repeated exposure to cocaine increases the release of glutamate, the excitatory neurotransmitter. Glutamate receptors, such as NMDA, in postsynaptic neurons, are activated by glutamate. Each of the several types of glutamate receptors is transcribed by different genes and their mRNA. 

There are two major types of receptor which are activated by neurotransmitters. These are the ionotropic and metabotropic receptors. The former receptor type is illustrated by the amino acid neurotransmitter receptors for glutamate, gamma-aminobutyric acid (GABA) and glycine, and the acetylcholine receptors of the nicotinic type. These are examples of fast transmitters in that they rapidly open and close the ionic channels in... 

There are several receptor subtypes for most neurotransmitters. These are distinguished numerically (e. g., Di to D5) or are named after their agonists—i.e., after molecules experimentally found to activate the receptor. For example, one specific subtype of glutamate receptors reacts to NMDA (N-methyl-D-aspartate), while another sub-type reacts to the compound AMPA, etc. 

Neurochemicals distinguish the reductionistic-type sensory pathways from the integrative-type action circuitry. Sensory pathways commonly use the excitatory neurotransmitters glutamate or aspartate at virtually every relay. Most actions along these pathways are mediated by the fast acting glutamate receptors ofthe iontropicvariety (i.e., AMPA and kainate receptors). Acetylcholine is... 

There are two main families of ligand-gated ion channel proteins that act as ionotropic receptors. One family includes the nicotinic acetylcholine receptor, the GABA-A receptor, the glycine receptor, and a class of serotonin receptor. The other family comprises various types of ionotropic glutamate receptors. Since these various ligand gated ion channels are activated by neurotransmitters, the medicinal chemistry of these proteins is presented in detail in chapter 4. 

Strong evidence indicates at least a familial pattern and perhaps a hereditary basis for some types of alcoholism ( 393). More recent data show that genotype accounts for approximately 33% of the overall variance in liability ( 394). In addition, specific neurocircuitry and neurochemical systems appear to be important in the etiology of alcoholism (395). Thus, positive reinforcement may be mediated by activation of g-aminobutyric acid (GABA) receptors, release of opioid peptides and dopamine, inhibition of glutamate receptors, and interactions with the 5-HT system. Furthermore, neurobehavioral effects of alcohol and their association with these various neurotransmitters serve as potential targets for novel drug therapies. 

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