Alpha-conotoxins EpI and AuIB switch subtype selectivity and activity in native versus recombinant nicotinic acetylcholine receptors.
FEBS Lett
; 554(1-2): 219-23, 2003 Nov 06.
Article
em En
| MEDLINE
| ID: mdl-14596943
ABSTRACT
The Xenopus laevis oocyte expression system was used to determine the activities of alpha-conotoxins EpI and the ribbon isomer of AuIB, on defined nicotinic acetylcholine receptors (nAChRs). In contrast to previous findings on intracardiac ganglion neurones, alpha-EpI showed no significant activity on oocyte-expressed alpha3beta4 and alpha3beta2 nAChRs but blocked the alpha7 nAChR with an IC50 value of 30 nM. A similar IC50 value (103 nM) was obtained on the alpha7/5HT3 chimeric receptor stably expressed in mammalian cells. Ribbon AuIB maintained its selectivity on oocyte-expressed alpha3beta4 receptors but unlike in native cells, where it was 10-fold more potent than native alpha-AuIB, had 25-fold lower activity. These results indicate that as yet unidentified factors influence alpha-conotoxin pharmacology at native versus oocyte-expressed nAChRs.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores Nicotínicos
/
Conotoxinas
Limite:
Animals
Idioma:
En
Revista:
FEBS Lett
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Austrália