Channelpedia

Nav2.3

Synonyms: nav2.3

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Introduction

mNav2.3 - a NaCh isoform that was investigated by cloning of a full-length cDNA from the mouse AT-1 atrial tumor cell line [891] - is overall 68% identical to hNav2.1 with similar sequence in functionally relevant regions such as pore-forming segments, positively charged S4 segments, and inactivation gate sequence. Analysis of the mNav2.3 mRNA expression during cardiac and skeletal muscle development indicates tight developmental control over gene expression while transcript levels in uterus during pregnancy vary and dramatically decrease following delivery. Taken together, these data indicate that the Na2 subfamily is conserved across species and likely to play important physiological roles in cardiac and uterine muscle. [872]


Experimental data


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Gene

Scn7a (also known as NaG; Nax; Nav2; Scn6a; Nav2.3; AI642000; 1110034K09Rik) encodes Nav2.3, the alpha unit of a voltage gated sodium channel, type VII, in Mus musculus. The human homologue of the gene is SCN7A (the same as for Nav2.1 and Nav2.2?). RGDID:1601888


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Transcript


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Ontology


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Interaction


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Protein


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Structure

mNa2.3 has four positively charged amino acids in the S4 domain or region in repeat segment four, whereas all other mammalian NaCs have twice this number. These findings suggest that mNa2.3 may encode NaCs with altered activation kinetics [873], [884].


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Distribution

mNa,2.3 expression in mouse heart localized with glial and axon-specific antibody binding. A similar staining pattern was observed in quiescent uterus. [876]


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Expression

mNav2.3 can be found in mouse atrial myocytes. [876]

Expression of mNav2.3 genes is most prominent in the heart and uterus of mouse and human, with lesser expression in skeletal muscle. [876], [873]

During late pregnancy the mNa,2.3 expression associated with nerve disappeared, probably due to the denervation that occurs during pregnancy [885],[886], [887], [888]. In contrast, mNa,2.3 expression appeared in both longitudinal and circular uterine smooth muscle. The myocyte expression of mNa,2.3 reached a maximum at term and quickly declined 2 days after delivery. [876]


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Functional

mNa2.3 contributes to the Na+ currents that have been recorded from pregnant uterine smooth muscle [889], [890] and suggest a role for NaCs in term myometrium. [876]


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Kinetics


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Model


References

884

Noda M. et al. Structural parts involved in activation and inactivation of the sodium channel.
Nature, 1989 Jun 22 , 339 (597-603).

885

Morizaki N. et al. A functional and structural study of the innervation of the human uterus.
Am. J. Obstet. Gynecol., 1989 Jan , 160 (218-28).

887

Thorbert G. et al. Regional changes in structure and function of adrenergic nerves in guinea-pig uterus during pregnancy.
Acta Obstet Gynecol Scand Suppl, 1978 , 79 (1-32).

889

Sperelakis N. et al. Fast Na+ channels in smooth muscle from pregnant rat uterus.
Can. J. Physiol. Pharmacol., 1992 Apr , 70 (491-500).

890

Young RC. et al. Characterization of sodium channels in cultured human uterine smooth muscle cells.
Am. J. Obstet. Gynecol., 1991 Jan , 164 (175-81).


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