Changing cation levels (Mg2+, Ca2+, Na+) alters the release of glutamate, GABA and other substances from the guinea pig cochlea

doi:10.1016/0378-5955(91)90143-W

Hearing Research

Volume 54, Issue 1, July 1991, Pages 135-144

https://doi.org/10.1016/0378-5955(91)90143-W Get rights and content

Abstract

We examined the effects of changes in cation levels (increased Mg²⁺ concentration combined with low Ca²⁺ concentration, and two low concentrations of Na⁺) on the perilymph levels of gamma-aminobutyric acid (GABA), glutamate (Glu), aspartate (Asp) and other substances. Artificial perilymph solutions containing normal (5 mM) and high (50 mM) levels of K⁺ were perfused through the perilymphatic compartment of the guinea pig cochlea to examine basal release (5 mM K⁺) and depolarization-induced release (50 mM K⁺). Each of the two K⁺ concentrations were contained in four different solutions: [I] normal artificial perilymph (NARP; Nacl, 137 mM; CaCl₂, 2 mM; MgCl₂, 1 mM;); [II] high Mg²⁺ (20 mM)/low Ca²⁺ (0.1 mM) (HMgLCa); [III] low Na⁺ (117 mM; LNa), and [IV] very low Na⁺ (NaCl, 0 mM; VLNa). The effluent was collected and assayed for eighteen primary amines by HPLC. Compared with NARP, the HMgLCa group had an increase in the high K⁺-induced release of Asp and Glu with no change in GABA. VLNa increased the normal K⁺ levels of Asp, Glu and GABA up to those observed with high K⁺ in NARP. VLNa increased the high K⁺ levels of Asp and Glu over fivefold compared with the high K⁺ levels in NARP, but decreased GABA. We ascribe the results to an interference with either a Na⁺-dependent uptake processes or a Na⁺/Ca²⁺ exchange carrier.

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Changing cation levels (Mg2+, Ca2+, Na+) alters the release of glutamate, GABA and other substances from the guinea pig cochlea

Abstract

Brain Res.

Neurosci. Let.

Brain Res.

Life Sci.

Brain Res.

Biochem. Pharmacol.

Neuroscience

Neuroscience

Hear. Res.

Brain Res.

Biochim. Biophys. Acta

J. Neurosci.

Hear. Res.

Biochem. Pharmacol.

Brain Res.

Brain Res.

Brain Res.

Neurochem. Int.

Efferent Neurotransmitters

Influence of perilymphatic tetrodotoxin and calcium concentration on hair cell function

Abstr. Assoc. Res. Otolaryngol

Stimulus-induced release of endogenous amino acids from skins containing the lateral-line organ in Xenopus laevis

Exp. Brain Res.

Neuro-transmission in the inner ear

Pharmacological approach of acoustic trauma in the cochlea

Changing cation levels (Mg²⁺, Ca²⁺, Na⁺) alters the release of glutamate, GABA and other substances from the guinea pig cochlea