Necessary additional research should make use of parallel recording of behavior and bioelectric brain activity as well as of the discoveries of molecular biology in order to further better understanding of the participation of ionotropic and metabotropic receptors
of inhibitory GABA mediators in learning.
Each neuron carries receptors for both excitatory and inhibitory neurotransmitters on its surface; moreover, some of the signals will be mediated through ionotropic receptors and induce fast responses whereas others will be mediated through metabotropic receptors
and trigger slow responses.
Thirteen chapters deal with N-methyl-n-aspartate (NMDA) receptors, 8 with 2-amino-3-hydroxy-5-methyl-4-isoxazole propicnic acid (AMPA) receptors, 6 with kainate receptors, and 6 with metabotropic receptors
Binding of glutamate to metabotropic receptors
involves guanosine nucleotide-binding protein (G-protein).
The modulation of glutamatergic ionotropic or metabotropic receptors
is shown in Table 4.
Glutamate is the primary excitatory neurotransmitter in the CNS of vertebrates, activating both ionotropic mad metabotropic receptors
44] These metabotropic receptors
are both autoreceptors and heteroreceptors that mediate the release of 5-HT and other neurotransmitters such as acetylcholine and glutamate.
It has been previously shown that the intrinsic biochemical steps of STM include the activation of glutamate NMDA, AMPA and metabotropic receptors
in the CAI region of the hippocampus, and that STM is activated by AMPA, but not NMDA receptors in the entorhinal cortex (Izquierdo et al.
Among the three known classes of GABA receptors, GABAa and GABAc ionotropic receptors (ion channels), and GABAb metabotropic receptors
(G protein-coupled receptors), the GABAa receptor is one of the most promising targets for a wide range of CNS-related diseases including anxiety, irritability, insomnia, and depression (Mohler et al.