Histamine stimulated synaptosomal Ca2+ uptake through activation of calcium channels.
Biochem Biophys Res Commun
; 153(3): 1136-43, 1988 Jun 30.
Article
em En
| MEDLINE
| ID: mdl-2455514
ABSTRACT
Histamine stimulated Ca2+ uptake in synaptosomes was completely inhibited by the slow Ca2+ channel antagonists verapamil, cinnarizine and flunarizine, and slightly inhibited by nifedipine and diltiazem. Ca2+ uptake in synaptosomes depolarized or predepolarized with varying K+ concentrations was increased by histamine, in both conditions, until 30mM K+. At higher K+ concentrations histamine was not able to alter K+ effects in either conditions. 30mM K+ stimulated uptake of Ca2+ in the absence or presence of histamine was not inhibited by verapamil and diltiazem. However nifedipine slightly inhibited K+ and K+ +histamine effects. 3-Isobutyl-1-methyl-xanthine and dibutyryl cyclicAMP potentiated (10%) the uptake of Ca2+ in synaptosomes induced by histamine. Dibutyryl cyclicAMP alone however decreased the basal Ca2+ uptake in a concentration-dependent manner. Verapamil, but not diltiazem, antagonized the effects elicited by 3-isobutyl-1-methyl-xanthine and dibutyryl cyclicAMP in the presence of histamine. The data suggest that the increase in synaptosomal Ca2+ uptake induced by histamine is mediated by the activation of the voltage sensitive calcium channels, and possibly a cyclicAMP-dependent protein kinase phosphorylation can modulate the opening of Ca2+ channels.
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Base de dados:
MEDLINE
Assunto principal:
Sinaptossomos
/
Histamina
/
Cálcio
/
Canais Iônicos
Limite:
Animals
Idioma:
En
Revista:
Biochem Biophys Res Commun
Ano de publicação:
1988
Tipo de documento:
Article
País de afiliação:
Espanha