Metabotropic glutamate receptors in cultured cerebellar granule cells: developmental profile.
Excitatory amino acid (EAA)-induced polyphosphoinositide (PPI) hydrolysis was studied during the development in culture of cerebellar granule cells. The developmental pattern was similar using metabotropic glutamate (Glu) receptor (mGluR) agonists, including L-Glu, quisqualate, and trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylic acid: The stimulation of [3H]inositol monophosphate ([3H]-InsP) formation was low at 2 days in vitro (DIV), but the response increased steeply, reaching a peak at 4 DIV, followed by a progressive decline. In contrast, carbamylcholine-induced PPI hydrolysis exhibited a plateau after a pronounced increase during the first week in vitro. At 6 DIV, but not at 4 DIV, when the activity peaked, PPI hydrolysis elicited by Glu was reduced by the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801, indicating that in cultured granule cells, NMDA receptors contribute to [3H]-InsP formation and that this component of the response develops relatively late. Accordingly, NMDA-induced [3H]-InsP formation, estimated under Mg(2+)-free conditions, increased markedly from very low values at 2 DIV to a plateau at 8-10 DIV. The developmental pattern of EAA-induced PPI hydrolysis was paralleled by changes in the level of an mRNA for a specific mGluR subtype (mGluR1 mRNA). RNA blot analysis performed with the pmGR1 cDNA probe revealed that the hybridization signal in RNA extracts from cultures at 1 DIV was very weak, but mGluR mRNA levels increased dramatically between 1 and 3 DIV, followed by a progressive decrease, so that by 15 DIV the mRNA levels were only approximately 10% of the values at 3 DIV.(ABSTRACT TRUNCATED AT 250 WORDS)
Aronica
E
E
Netherlands Institute for Brain Research, Amsterdam.
Condorelli
D F
DF
Nicoletti
F
F
Dell'Albani
P
P
Amico
C
C
Balázs
R
R
D000704:Analysis of Variance; D000818:Animals; D015152:Blotting, Northern; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism*; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D007294:Inositol / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism; D007700:Kinetics; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000378:metabolism; D012313:RNA / Q000302:isolation & purification / Q000378:metabolism; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D017470:Receptors, Glutamate / Q000235:genetics / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D013997:Time Factors
D005971:Glutamates; D007295:Inositol Phosphates; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D012333:RNA, Messenger; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C002647:inositol 1-phosphate; D018698:Glutamic Acid; D007294:Inositol; D012313:RNA; D016291:Dizocilpine Maleate