A simple but effective coupling of microdialysis and capillary electrophore
sis with laser induced fluorescence detection technique was applied to anal
ysis of amino acid neurotransmitters in the hypothalamus of rats after acut
e exhausting exercise. The separation of amino acids was achieved using an
uncoated fused-silica capillary (57 cm x 75 mum I.D.) with a buffer of 10 m
M disodium tetraborate at pH 10 and an applied voltage of 12.5 kV. The dete
ction limit was 10(-10) M for each amino acid. It is sufficiently sensitive
and rapid for the determination of amino acids in a 5-mul Microdialysate.
In comparison to pre-exercise, a significant increase in the levels of six
hypothalamic amino acids (arginine, glycine, lysine, glutamic acid, alanine
, gamma -amino-n-butyric acid) was found after exercise. These results demo
nstrate that the increase of metabolic amino acids in the hypothalamus of r
ats can be induced by exhausting exercise and suggests that amino acid neur
otransmitters may play functional roles in the central effects of exercise.
(C) 2001 Elsevier Science B.V. All rights reserved.