cAMP-activated chloride currents in amphibian retinal pigment epithelial cells.
AUTOR(ES)
Hughes, B A
RESUMO
1. The effect of cAMP on whole-cell currents in isolated retinal pigment epithelial (RPE) cells of the bullfrog and marine toad was investigated by means of the perforated patch clamp technique. 2. Superfusing cells with either cAMP or forskolin led to the development of a time-independent current that had a linear current-voltage (I-V) relationship. The reversal potential of (Vrev) of the cAMP-activated current was unaffected by the removal of either Na+ or HCO3- from the external and internal solutions or by the addition of extracellular barium, but it was near the Cl- equilibrium potential (ECl) over a wide range of extracellular Cl- concentrations, suggesting the presence of a Cl(-)-selective channel. 3. The anion permeability sequence of the cAMP-activated conductance calculated from biionic reversal potentials was NO3- = I- > Br- > Cl- >> HCO3- > methanesulphonate. 4. The conductance was blocked by a variety of Cl- transport inhibitors, including 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), 4,4'-dinitro-2,2'- stilbene disulphonic acid (DNDS), frusemide, N-phenylanthranilic acid (DPC) and niflumic acid. 5. The present study demonstrates that cAMP activates a Cl(-)-selective channel that most probably resides in the basolateral membrane.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1175501Documentos Relacionados
- Swelling- and cAMP-activated Cl- currents in isolated rat carotid body type I cells.
- Antisense oligodeoxynucleotides to the cystic fibrosis transmembrane conductance regulator inhibit cAMP-activated but not calcium-activated chloride currents.
- Properties of the cAMP-activated C1- current in choroid plexus epithelial cells isolated from the rat.
- Co-regulation of cAMP-activated Na+ current by Ca2+ in neurones of the mollusc Pleurobranchaea.
- Cloning and expression of a cAMP-activated Na+/H+ exchanger: evidence that the cytoplasmic domain mediates hormonal regulation.