We have previously shown that epithelial Na+ channels in mouse mandibular gland duct cells are controlled by cytosolic Na+ and Cl−, acting, respectively, via G o and G i proteins. Since we found no evidence for control of epithelial Na+ channels by extracellular Na+ ([Na+] o ), our findings conflicted with the long-held belief that Na+ channel activators, such as sulfhydryl reagents, like para-chloromercuriphenylsulfonate (PCMPS), and amiloride analogues, like benzimidazolylguanidinium (BIG) and 5-N-dimethylamiloride (DMA), induce their effects by blocking an extracellular channel site which otherwise inhibits channel activity in response to increasing [Na+] o . Instead, we now show that PCMPS acts by rendering epithelial Na+ channels refractory to inhibition by activated G proteins, thereby eliminating the inhibitory effects of cytosolic Na+ and Cl− on Na+ channel activity. We also show that BIG, DMA, and amiloride itself, when applied from the cytosolic side of the plasma membrane, block feedback inhibition of Na+ channels by cytosolic Na+, while leaving inhibition by cytosolic Cl− unaffected. Since the inhibitory effects of BIG and amiloride are overcome by the inclusion of the activated α-subunit of G o in the pipette solution, we conclude that these agents act by blocking a previously unrecognized intracellular Na+ receptor.
The Journal of Membrane Biology – Springer Journals
Published: Apr 1, 1998
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera