Modulation by Calcium of Deiters' Neuron Gabaa Receptors in the Rabbit

• Published in: International journal of neuroscience 1997-01, Vol.90 (3-4), p.169-176
• Main Authors: Hydén, Holger, Cupello, Aroldo, Rapallino, Maria V.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Calcium - pharmacology; Calcium ions; Cell Membrane Permeability - drug effects; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Deiters' neurons; Egtazic Acid - metabolism; Fundamental and applied biological sciences. Psychology; GABA; GABAA receptors; gamma-Aminobutyric Acid - metabolism; Intracellular Membranes - metabolism; Male; micromethods; neuronal inhibition; Rabbits; Receptors, GABA - drug effects; Vertebrates: nervous system and sense organs; Vestibular Nucleus, Lateral - drug effects
• ISSN: 0020-7454; 1563-5279; 1543-5245
• DOI: 10.3109/00207459709000636

The function of classical GABAA receptors of the rabbit Deiters' neurons has been studied at the single membrane level by a biochemical micromethod involving the study of labelled chloride permeation. In particular, labelled chloride permeation across microdissected fresh single membranes was studied in a microchamber system. The stimulation of 36Cl− out in permeation by "extracellular" GABA was determined under different conditions in the respect of Ca++. When the conditions were such that "intracellular" Ca++ was 0.02 μ there appeared to be an optimal effect by GABA on chloride passage. Conditions presumably resulting in an increase of [Ca++]i beyond the level reported above led to a decreased GABA effect, especially at the highest GABA concentrations used (± lO−4M). However, complete removal of Ca++ by a high (12mM) intracellular EGTA concentration erased completely the GABA effect.