Article date: 1988/1/1
PubMed ID: 2848169
Journal name: Life sciences (ISSN: 0024-3205)
Gamma-aminobutyric acid (GABA), glutamate decarboxylase and GABA-transaminase were identified in the nematode Caenorhabditis elegans. The concentration of GABA in C. elegans (0.14 micrograms/mg protein) is approximately 10-fold lower than the concentration of GABA in rat brain. Glutamate decarboxylase and GABA-transaminase, the GABA anabolic and catabolic enzymes, are also present in C. elegans. Crude membrane fractions were prepared from C. elegans and used to study specific [3H] GABA binding sites. GABA binds to C. elegans membranes with high affinity (37 nM) and low capacity (Bmax = 2.25 pmol/mg protein). Muscimol is a competitive inhibitor of specific GABA binding with a KI value of 120 nM. None of the other GABA agonists or antagonists inhibited greater than 40% of the specific GABA binding at concentrations up to 10(-4)M. Thirteen spider venoms were examined as possible GABA agonists or antagonists, the venom from Calilena agelenidae inhibits specific GABA binding with a KI value of 6 nl/ml. These results suggest that GABA has a physiological role as a neurotransmitter in C. elegans.
Author List: Schaeffer J M, Bergstrom A R
Publication Types: Comparative Study; Journal Article
Substances mentioned in the article: Receptors, GABA-A; gamma-Aminobutyric Acid; 4-Aminobutyrate Transaminase; Glutamate Decarboxylase;
Mesh terms: 4-Aminobutyrate Transaminase/metabolism; Animals; Brain/metabolism; Caenorhabditis/metabolism; Cell Membrane/metabolism; Glutamate Decarboxylase/metabolism; Kinetics; Organ Specificity; Rats; Receptors, GABA-A/metabolism; Species Specificity; gamma-Aminobutyric Acid/metabolism;