RGD Reference Report - Non-L-type voltage-dependent calcium channels control vascular tone of the rat basilar artery. - Rat Genome Database

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Non-L-type voltage-dependent calcium channels control vascular tone of the rat basilar artery.

Authors: Navarro-Gonzalez, MF  Grayson, TH  Meaney, KR  Cribbs, LL  Hill, CE 
Citation: Navarro-Gonzalez MF, etal., Clin Exp Pharmacol Physiol. 2009 Jan;36(1):55-66. Epub 2008 Aug 26.
RGD ID: 2308879
Pubmed: PMID:18759855   (View Abstract at PubMed)
DOI: DOI:10.1111/j.1440-1681.2008.05035.x   (Journal Full-text)

1. Constriction of cerebral arteries is considered to depend on L-type voltage-dependent calcium channels (VDCCs); however, many previous studies have used antagonists with potential non-selective actions. Our aim was to determine the expression and function of VDCCs in the rat basilar artery. 2. The relative expression of VDCC subtypes was assessed using quantitative polymerase chain reaction and immunohistochemistry. Data were correlated with physiological studies of vascular function. Domains I-II of the T channel subtypes expressed in the rat basilar artery were cloned and sequenced. 3. Blockade of L-type channels with nifedipine had no effect on vascular tone. In contrast, in the presence of nifedipine, hyperpolarization of short arterial segments produced relaxation, whereas depolarization of quiescent segments evoked constriction. 4. The mRNA and protein for L- and T-type VDCCs were strongly expressed in the main basilar artery and side branches, with Ca(V)3.1 and Ca(V)1.2 the predominant subtypes. 5. T-Type VDCC blockers (i.e. 1 micromol/L mibefradil, 10 micromol/L pimozide and 100 micromol/L flunarizine) decreased intracellular calcium in smooth muscle cells, relaxed and hyperpolarized arteries, whereas nickel chloride (100 micromol/L) had no effect. In contrast with nifedipine, 10 micromol/L nimodipine produced hyperpolarization and relaxation. 6. When arteries were relaxed with 10 micromol/L U73122 (a phospholipase C inhibitor) in the presence of nifedipine, 40 mmol/L KCl evoked depolarization and constriction, which was significantly reduced by 1 micromol/L mibefradil. 7. Sequencing of domains I-II revealed splice variants of Ca(V)3.1, which may impact on channel activity. 8. We conclude that vascular tone of the rat basilar artery results from calcium influx through nifedipine-insensitive VDCCs with pharmacology consistent with Ca(V)3.1 T-type channels.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
artery smooth muscle contraction  IMP 2308879 RGD 
positive regulation of cytosolic calcium ion concentration  IMP 2308879 RGD 

Cellular Component
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
perinuclear region of cytoplasm  IDA 2308879 RGD 

Molecular Function
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
low voltage-gated calcium channel activity  IDA 2308879 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Cacna1g  (calcium voltage-gated channel subunit alpha1 G)


Additional Information