(1) Either of these receptors has an excitatory or inhibitory effect on the end organ.(2) In the brain, 80% of manganese is found in the enzyme glutamine synthetase, which inactivates the excitatory amino acid glutamate to glutamine.(3) In order to bring normal balance between excitatory and inhibitory postsynaptic potential, antiseizure drugs may use one or more of the following mechanisms.(4) The responsible nerves appear to include both excitatory cholinergic fibers and inhibitory fibers that probably release nitric oxide.(5) Spontaneous central excitatory phenomena and a reduction in flow demand help mitigate the effect of attenuation of chemical and neuromechanical compensatory responses that characterizes REM sleep.(6) In the esophagus, most investigators have observed excitatory effects in the form of an increased incidence of nonpropulsive contractions or an increased contraction force.(7) However, in other cases, it may be associated with a biochemical and/or physiological defect in the brain of the patient with epilepsy presumably due to an imbalance of excitatory and inhibitory neurotransmitters.(8) The need to develop a medication that is consistently effective for cocaine abuse has brought attention to another class of agents called excitatory amino acid antagonists.(9) In the heart, arrhythmias arise due to metabolic deficiencies; these are interpreted as originating directly from the excitatory muscle tissue sensitive to acidosis.(10) If an excitatory input, associated with hypoxia, was received by the respiratory motor centers in the brainstem, an increase in respiratory activity should have resulted.(11) Neurosteroids can therefore alter neuronal excitability very rapidly by binding to receptors for inhibitory or excitatory neurotransmitters at the cell membrane.(12) Verbal disapproval, when used alone, has been shown to increase noncompliance, and shouted commands often result in excitatory effects in preschoolers.(13) Ampakine drugs enhance excitatory communication, thereby partially or completely restoring the brains excitatory communication.(14) Two kinds of motor nerves, excitatory nerves that release acetylcholine and inhibitory nerves that release nitric oxide, account for all events that occur in smooth muscle of the esophagus in a swallow.(15) The active transport mechanism for methylfolate across the blood-brain barrier strictly limits the entry of the vitamin, perhaps for reasons concerned with the excitatory properties of folic acid.(16) Norepinephrine and serotonin may be excitatory or inhibitory, but they are functionally inhibitory on pain transmission; glutamate is the other important excitatory neurotransmitter.
