Tp. Hicks et F. Conti, AMINO-ACIDS AS THE SOURCE OF CONSIDERABLE EXCITATION IN CEREBRAL-CORTEX, Canadian journal of physiology and pharmacology, 74(4), 1996, pp. 341-361
A number of different factors contributed to the rationale for providi
ng a critical review of the field of excitatory amino acids in the cer
ebral cortex at this time. In addition to the recent growing realisati
on by clinicians that the excitatory amino acids are linked critically
to a number of neurological conditions, including neurodegenerative s
yndromes such as Alzheimer's disease, cortical damage due to stroke an
d cerebral ischemia, epilepsy, amyotropic lateral sclerosis, and schiz
ophrenia, the recent cloning and membrane reconstitution of specific r
eceptors known as AMPA, NMDA, kainate, and metabotropic receptors and
their known subunits have prompted a surge of renewed interest in this
important family of synaptic transmitter molecules. Moreover, recent
advances in our understanding of the molecular events involved in grow
th promotion in the early stages of the development of the cortex have
shown that both NMDA and non-NMDA receptor subtypes perform important
roles in certain aspects of target selection and neurite outgrowth, i
n cone stimulation and guidance, and in spine formation and morphologi
cal alterations. A recent explosive growth in interest in the possible
roles of nitric oxide and related short-lived radicals in plasticity,
disease, and synaptic transmission also is related closely with the a
ctions of excitatory amino acids. All these relatively new advances ha
ve transpired in parallel with ongoing work that has extended our appr
eciation for the roles of excitatory amino acids in the areas of synap
tic plasticity (long-term potentiation, long-term depression, receptiv
e field reorganisation following drug-induced or peripheral sensory di
sturbances, such as denervation or amputation), in processes of normal
transmission at functionally and electrophysiologically identified ne
urones of the cerebral cortex, and in distinct proposed roles for cort
ical glia. A greater appreciation of the diverse types and properties
of the burgeoning family of receptors for the metabotropic receptor al
so contributed to our desire to feature that aspect of the field in th
e context of glia and neurones of the cerebral cortex. That part of th
e field of neuroscience concerned with the functions of excitatory ami
no acids has grown so large over the past 10 years or so, that a revie
w paper focusing on the contributions to a specialized meeting devoted
solely to cerebral cortex could easily be supported by material compr
ising a sufficient body of communications from top-quality research la
boratories. The present account endeavours to summarize and discuss th
e biochemical characteristics, physiological roles, pharmacological pr
operties, clinical relevance, developmental involvements, and anatomic
al-morphological aspects pertaining to the excitatory amino acid trans
mitters in cerebral cortex.