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

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 microM 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 (> or = 10(-4)M). However, complete removal of Ca++ by a high (12 mM) intracellular EGTA concentration erased completely the GABA effect. These results indicate that in these neurons an optimal GABAA receptor function requires [Ca++]i levels well below micromolar. The high [EGTA]i effect seems to imply that too low a [Ca++]i is also harmful to the proper function of these GABAA receptors. However, an alternative explanation is possible. -->

ISSN:	1543-5245 0020-7454
DOI:	10.3109/00207459709000636
Přístupová URL adresa:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1db5ba2c4300cff69344ba4ad2bf3dcf https://doi.org/10.3109/00207459709000636
Přírůstkové číslo:	edsair.doi.dedup.....1db5ba2c4300cff69344ba4ad2bf3dcf
Autor:	Aroldo Cupello, Holger Hydén, M. V. Rapallino
Rok vydání:	1997
Předmět:	Male medicine.medical_specialty Cell Membrane Permeability chemistry.chemical_element Stimulation Calcium chemistry.chemical_compound Receptors GABA Internal medicine medicine Extracellular Animals Egtazic Acid gamma-Aminobutyric Acid GABAA receptor Vestibular Nucleus Lateral General Neuroscience Vestibular pathway Intracellular Membranes General Medicine EGTA medicine.anatomical_structure Endocrinology nervous system chemistry Biophysics Rabbits Neuron Intracellular
Zdroj:	International Journal of Neuroscience. 90:169-176
ISSN:	1543-5245 0020-7454
DOI:	10.3109/00207459709000636
Popis:	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 microM 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 (> or = 10(-4)M). However, complete removal of Ca++ by a high (12 mM) intracellular EGTA concentration erased completely the GABA effect. These results indicate that in these neurons an optimal GABAA receptor function requires [Ca++]i levels well below micromolar. The high [EGTA]i effect seems to imply that too low a [Ca++]i is also harmful to the proper function of these GABAA receptors. However, an alternative explanation is possible.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1db5ba2c4300cff69344ba4ad2bf3dcf https://doi.org/10.3109/00207459709000636 Zobrazit plný text záznamu Plný text ve formátu PDF