1. In isolated dorsal root ganglion cells (DRG neurons), changes in the concentration of global cytosolic Ca2+ (delta (Ca2+)c) were measured by the fluorescence of K5‐indo‐1. Depolarizations from ‐60 to 0 mV (500 ms) and Ca2+ influx through Ca2+ channels (ICa) increased (Ca2+)c by 480 +/‐ 113 nM, the peak occurring 542 +/‐ 76 ms (mean +/‐ S.E.M.) after repolarization. 2. Ryanodine (10 microM) reduced depolarization‐induced delta (Ca2+)c by up to 80% and blocked delta (Ca2+)c induced by 20 mM caffeine. 3. Peak delta (Ca2+)c and peak ICa followed a similar bell‐shaped voltage dependence. Removal of extracellular Ca2+ abolished depolarization‐induced delta (Ca2+)c; its elevation from 2 to 8 mM increased peak ICa by 30% and delta (Ca2+)c by 108%. 4. Ca2+ influx at 0 mV was graded by pulse durations between 20 and 500 ms. Up to 200 ms, delta (Ca2+)c increased linearly with Ca2+ influx. Depolarizations longer than 200 ms induced a supralinear increase in delta (Ca2+)c that was abolished by caffeine (20 mM). 5. The supralinear increase in delta (Ca2+)c and the caffeine‐induced delta (Ca2+)c were measured only in thirteen of nineteen DRG neurons; in the other six of nineteen cells both properties were absent. The results suggest that Ca(2+)‐induced Ca2+ release (CICR) is expressed differently in different populations of DRG neurons. 6. A single action potential did not significantly increase (Ca2+)c. Trains of stimuli (20 Hz) induced delta (Ca2+)c that linearly increased with the number of action potentials. Delta (Ca2+)c due to 100 action potentials had a significant ryanodine‐sensitive component. 7. It is discussed that CICR can contribute to the depolarization‐induced (Ca2+)c, provided the Ca2+ influx lasts for a certain minimum period of time.
The Journal of Physiology – Wiley
Published: Dec 15, 1995
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