Regional in vivo superfusion of the spinal cord and KC1-induced amino acid release.
In vivo push-pull superfusion was used to sample the regional release of amino acids into spinal superfusates of urethane-anesthetized rats. By collecting superfusates from the intrathecal space surrounding the sacral-lower thoracic spinal cord, it was possible to achieve a stable release of amino acids in one- and five-minute superfusate fractions. Introducing the depolarizing agent, potassium chloride (KC1) (40 mM), into the superfusion medium significantly increased GLU, GLY, and TAU concentrations in superfusates compared to pre-KCl values. The findings that these three amino acids were the only ones (out of 20) that showed a significant increase in response to KCl administration, suggest that they mediate neurotransmission in this region of the spinal cord. Amino acid concentrations were determined in spinal superfusates by high performance liquid chromatography (HPLC), utilizing an automated ortho-phthaldialdehyde precolumn derivatization system. The regional superfusion system described in this paper provides a technique for measuring KC1-produced release of neurochemicals that may mediate neurotransmission in delimited spinal regions.
Masters
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DB
Institute of Animal Behavior, Rutgers, State University of New Jersey, Newark 07102.
Jordan
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F
Komisaruk
B R
BR
D000596:Amino Acids / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D005260:Female; D010477:Perfusion / Q000379:methods; D011189:Potassium Chloride / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D013268:Stimulation, Chemical; D013997:Time Factors
D000596:Amino Acids; D011189:Potassium Chloride