Motor unit hyperexcitability in amyotrophic lateral sclerosis vs amino acids acting as neurotransmitters.
OBJECTIVE
Electrophysiological studies of amyotrophic lateral sclerosis (ALS) patients reveal not only lower motor neuron involvement, but also widespread signs of its hyperexcitability. They might be the consequence of changes in the level of amino acids acting as neurotransmitters.


METHODS
Electrophysiological examination of 31 patients with sporadic ALS was performed. A hyperexcitability index (HI) was created to describe the amount of double discharges, fasciculation potentials or 'giant' F-waves. Glutamate, aspartate, glycine and GABA concentration in serum and cerebrospinal fluid (CSF) were estimated, using the high performance liquid chromatography technique.


RESULTS
The electrophysiological studies revealed marked variability in HI in the patients group. HI did not correlate with duration of the disease and the degree of disability expressed with Norris score, as well as with the level of excitatory or inhibitory amino acids in the body fluids.


CONCLUSIONS
Hyperexcitability of the motor unit observed in ALS is not directly related to changes in serum and CSF level of amino acids acting as neurotransmitters.
Kostera-Pruszczyk
A
A
Department of Neurology, Medical University of Warsaw, Poland. akostera@amwaw.eddu.pl
Niebroj-Dobosz
I
I
Emeryk-Szajewska
B
B
Karwańska
A
A
Rowińska-Marcińska
K
K
D000328:Adult; D000368:Aged; D000596:Amino Acids / Q000097:blood / Q000134:cerebrospinal fluid; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology*; D001224:Aspartic Acid / Q000097:blood / Q000134:cerebrospinal fluid; D002851:Chromatography, High Pressure Liquid; D004576:Electromyography; D005260:Female; D018698:Glutamic Acid / Q000097:blood / Q000134:cerebrospinal fluid; D005998:Glycine / Q000097:blood / Q000134:cerebrospinal fluid; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology; D018377:Neurotransmitter Agents / Q000097:blood / Q000134:cerebrospinal fluid; D012016:Reference Values; D005680:gamma-Aminobutyric Acid / Q000097:blood / Q000134:cerebrospinal fluid
D000596:Amino Acids; D018377:Neurotransmitter Agents; D001224:Aspartic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005998:Glycine