Properties of large conductance Ca2+-activated K+ channels were studied in the soma of motoneurones visually identified in thin slices of neonatal rat spinal cord. The channels had a conductance of 82 ± 5 pS in external Ringer solution (5.6 mm K+ o //155 mm K+ i ) and 231 ± 4 pS in external high-K o solution (155 mm K+ o //155 mm K+ i ). The channels were activated by depolarization and by an increase in internal Ca2+ concentration. Potentials of half-maximum channel activation (E50) were −13, −34, −64 and −85 mV in the presence of 10−6, 10−5, 10−4 and 10−3 m internal Ca2+, respectively. Using an internal solution containing 10−4 m Ca2+, averaged KCa currents showed fast activation within 2–3 msec after a voltage step to +50 mV. Averaged KCa currents did not inactivate during 400 msec voltage pulses. External TEA reduced the apparent single-channel amplitude with a 50% blocking concentration (IC50) of 0.17 ± 0.02 mm. KCa channels were completely suppressed by externally applied 100 mm charybdotoxin. It is concluded that KCa channels activated by Ca2+ entry during the action potential play an important role in the excitability of motoneurones.
The Journal of Membrane Biology – Springer Journals
Published: Mar 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