The GABA dose/conductance relationship on lobster muscle

J Physiol (Paris). 1979;75(6):645-9.

Abstract

A quantitative study was made of the action of GABA, some structurally-related agonists and antagonists on the dactyl opener muscle fibres of the lobster. It was concluded that the GABA dose/conductance relationship was better described by a two independent binding-site receptor model (with KII = 30 microM) than by a single-site or a two-site high co-operativity model. The dose/conductance curves for gamma-amino-beta-hydroxybutyric acid (GABOB), delta-aminovaleric acid (DAV) and piperazine indicated 'full' agonist behaviour, whereas those for guanidoacetic acid (GuAc) indicated a partial agonist action. beta-guanidinopropionic acid (beta-GP) and gamma-guanidinobutyric acid (gamma-GB) behaved as weak competitive GABA antagonists. Bicuculline was found to antagonize GABA non-competitively on the lobster as in the crayfish, whereas picrotoxin appeared to act in a 'mixed' antagonistic fashion.

MeSH terms

  • Amino Acids / pharmacology
  • Amino Acids, Neutral*
  • Animals
  • Bicuculline / pharmacology
  • Dose-Response Relationship, Drug
  • Electric Conductivity
  • GABA Antagonists
  • Glycine / analogs & derivatives
  • Glycine / pharmacology
  • Guanidines / pharmacology
  • In Vitro Techniques
  • Muscles / drug effects*
  • Nephropidae
  • Picrotoxin / pharmacology
  • Piperazines / pharmacology
  • Propionates / pharmacology
  • Valerates / pharmacology
  • gamma-Aminobutyric Acid / analogs & derivatives
  • gamma-Aminobutyric Acid / pharmacology*

Substances

  • Amino Acids
  • Amino Acids, Neutral
  • GABA Antagonists
  • Guanidines
  • Piperazines
  • Propionates
  • Valerates
  • Picrotoxin
  • gamma-guanidinobutyric acid
  • 4-amino-3-hydroxybutyric acid
  • gamma-Aminobutyric Acid
  • 5-aminovaleric acid
  • glycocyamine
  • Glycine
  • guanidinopropionic acid
  • Bicuculline