In vivo modification of GABAA receptor with a high dose of pyridoxal phosphate induces tonic-clonic convulsion in immature mice.
Neurochem Int
; 26(4): 369-73, 1995 Apr.
Article
em En
| MEDLINE
| ID: mdl-7633329
ABSTRACT
The biologic cofactor, pyridoxal-5'-phosphate (PLP), is responsible for tonic-clonic convulsion in immature mice. The mechanisms underlying such convulsive fits induced by administration of a single high dose of PLP were studied. The administration of PLP resulted in a 13% increase of PLP in the P2 fraction compared to control P2, and the calculated data suggested that membrane bound PLP increased over 31% (approximately 1 microM). The P2 fraction of administered mice was treated with [3H]NaBH4 and analyzed by SDS-polyacrylamide gel electrophoresis. The radioactivity was mainly incorporated into a 52 kDa protein which corresponded to a GABAA receptor subunit. The addition of PLP in vitro competitively inhibited [3H]GABA binding as well as [3H]flunitrazepam binding to synaptic membranes in a concentration-dependent manner, and 50% inhibition was achieved with 1 mM PLP. The results obtained in the present study demonstrate that PLP was rapidly permeable into the brain through the immature blood-brain barrier and then bound directly to GABAA receptor. It is probable that specific amino groups of lysine residues on the GABAA receptor react in vivo with PLP to form Schiff bases, and that the in vivo modification of the receptor produces a degeneration of GABAergic neurotransmission leading to the onset of a convulsive fit.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfato de Piridoxal
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Encéfalo
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Epilepsia Tônico-Clônica
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Receptores de GABA-A
Limite:
Animals
Idioma:
En
Revista:
Neurochem Int
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Japão
País de publicação:
ENGLAND
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ESCOCIA
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GB
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GREAT BRITAIN
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INGLATERRA
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REINO UNIDO
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SCOTLAND
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UK
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UNITED KINGDOM