Choline induces Ca2+ entry in cultured sympathetic neurones isolated from rat superior cervical ganglion.
Eur J Pharmacol
; 471(3): 165-76, 2003 Jun 27.
Article
em En
| MEDLINE
| ID: mdl-12826235
ABSTRACT
Choline has been shown to be a specific agonist at alpha7 nicotinic acetylcholine receptors, which are the most Ca(2+) permeable of the ionotropic receptor channels. Whole-cell patch recording combined with the measurement of intracellular free Ca(2+) concentration ([Ca(2+)](i), using Indo1, in cultured rat superior cervical ganglion neurones demonstrated that application of choline induced a slowly desensitizing inward current and increased [Ca(2+)](i). The effect was dose dependent with an EC(50) of 1.6 mM and an n(H) of 1.19. The relationship between the elevation of [Ca(2+)](i) (Delta[Ca(2+)](i)) and charge transfer analysed under various recording conditions showed that the Delta[Ca(2+)](i) induced by choline resulted from an influx of Ca(2+) through nicotinic acetylcholine receptors. The effect of choline on the membrane current and Delta[Ca(2+)](i) was not affected by either short application or pretreatment with alpha-bungarotoxin (50 nM) and methyllycaconitine (1 nM), two alpha7 nicotinic receptors antagonists. These results indicate that activation of non-alpha7 nicotinic acetylcholine receptors by choline significantly increases the Ca(2+) concentration in rat superior cervical ganglion neurones.
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Base de dados:
MEDLINE
Assunto principal:
Cálcio
/
Colina
/
Gânglio Cervical Superior
/
Fibras Adrenérgicas
Limite:
Animals
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article