Larval bullfrog skin expresses ENaC despite having no amiloride-blockable transepithelial Na+ transport
| Autor: | Thomas C. Cox, Philip J. Jensik, Makoto Takada, Shigeru Hokari, Tomoko Shimomura |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Epithelial sodium channel
medicine.medical_specialty Physiology Protein subunit Biology Biochemistry Antibodies Sodium Channels Amiloride chemistry.chemical_compound Endocrinology Bullfrog Internal medicine medicine Animals RNA Messenger Epithelial Sodium Channels Ecology Evolution Behavior and Systematics Skin Rana catesbeiana Aldosterone Receptors Purinergic P2 urogenital system Vesicle respiratory system Prolactin Cell biology chemistry Receptors Purinergic P2X Larva Animal Science and Zoology Frog Skin hormones hormone substitutes and hormone antagonists Sodium Channel Blockers medicine.drug |
| Zdroj: | Journal of Comparative Physiology B. 176:287-293 |
| ISSN: | 1432-136X 0174-1578 |
| DOI: | 10.1007/s00360-005-0050-y |
| Popis: | Amiloride-blockable Na(+) transport, measured as an amiloride-blockable short-circuit current (Am-SCC), is mediated by the epithelial Na(+) channel (ENaC). Am-SCC is not normally present in bullfrog tadpole skin, but when such skin is cultured with corticoids an amiloride-blockable Na transport appears. Prolactin (PRL) inhibits its corticoid-induced development. Using specific PCR primers for adult frog ENaC and RT-PCR, we investigated whether corticoids can induce all three ENaC subunits, and whether this expression of ENaC subunit(s) can be blocked by adding PRL with the corticoids. We found that (1) the sequences of the RT-PCR products obtained using primers for alpha-ENaC were identical between larval and adult skins, (2) the mRNAs for all three ENaC subunits were expressed in larval skin under normal conditions despite no amiloride-blockable Na(+) transport being detectable, (3) all three subunits were expressed in larval skins whether they were cultured with corticoids (amiloride-blockable Na transport present) or with corticoids supplemented with PRL (no amiloride-blockable Na transport present). An antibody against a peptide from the alpha-ENaC of adult bullfrog was localized to the apical cells of both larval and adult skins. Since no amiloride-blockable Na transport exists across larval skin under these conditions, these results suggest that ENaC protein was expressed prior to the onset of transport. ENaC may be in the plasma membrane in an inactivated form or, alternatively, within vesicles waiting to be inserted. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink