Korean J Physiol Pharmacol.  1998 Feb;2(1):41-48.

Differential effect of homocysteic acid and cysteic acid on changes of inositol phosphates and (Ca2+)i in rat cerebellar granule cells

• Kim WK
• Pae YS

Abstract

The present study was undertaken to characterize homocysteic acid (HCA)-and cysteic acid (CA)mediated formation of inositol phosphates (InsP) in primary culture of rat cerebellar granule cells. HCA and CA stimulated InsP formation in a dose-dependent manner, which was prevented by the N-methyl-D-aspartate (NMDA) receptor antagonist D,L-2-amino-5-phosphopentanoic acid (APV). CA-, but not HCA-, mediated InsP formation was in part prevented by the metabotropic glutamate receptor antagonist alpha-methyl-4-carboxyphenylglycine ((+/-)-MCPG). Both HCA- and CA-mediated increases in intracellular calcium concentration were completely blocked by APV, but were not altered by (+/-)-MCPG. CA-mediated InsP formation was in part prevented by removal of endogenous glutamate. In contrast, the glutamate transport blocker L-aspartic acid-beta-hydroxamate synergistically increased CA responses. These data indicate that in cerebellar granule cells HCA mediates InsP formation wholly by activating NMDA receptor. In contrast, CA stimulates InsP formation by activating both NMDA receptor and metabotropic glutamate receptor, and in part by releasing endogenous glutamate into extracellular milieu.

Keyword

Homocysteic acid; Cysteic acid; Cerebellar granule cell; Primary culture; Inositol phosphates; [Ca2+]i; N-methyl-D-aspartate (NMDA) receptor; Metabotropic glutamate (mGlu) receptor

MeSH Terms

Animals
Calcium
Cysteic Acid*
Glutamic Acid
Inositol Phosphates*
Inositol*
N-Methylaspartate
Rats*
Receptors, Metabotropic Glutamate
Calcium
Cysteic Acid
Glutamic Acid
Inositol
Inositol Phosphates
N-Methylaspartate
Receptors, Metabotropic Glutamate