Uptake of GABA by bovine adrenal medulla slices.
A sodium dependent GABA uptake system has been found in bovine adrenal medulla slices. This uptake has a Km of 83.19 +/- 38.45 microM and a Vmax of 9.20 +/- 1.36 pmol/min X mg of tissue. It was inhibited by nipecotic acid and 2,4-diaminobutyric acid (IC50 67 and 38.5 microM, respectively) but not by beta-alanine at concentrations up to 5 mM, a result which is similar to those found for the neuronal GABA uptake rather than the glial uptake. It is suggested that GABA uptake together with catabolic action of GABA-transaminase, also found in this tissue, could be regulating the GABA levels disposable for the proposed modulator role on catecholamine secretion of this amino acid in adrenal medulla.
D000313:Adrenal Medulla / Q000378:metabolism*; D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D005947:Glucose / Q000494:pharmacology; D007700:Kinetics; D009557:Nipecotic Acids / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011392:Proline / Q000031:analogs & derivatives*; D012964:Sodium / Q000378:metabolism; D013997:Time Factors; D015091:beta-Alanine / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000613:Aminobutyrates; D009557:Nipecotic Acids; D015091:beta-Alanine; C030278:nipecotic acid; C005959:2,4-diaminobutyric acid; D005680:gamma-Aminobutyric Acid; D011392:Proline; D012964:Sodium; C010983:homoproline; D005947:Glucose; D011188:Potassium