>After an action potential, the intracellular Ca++ concentration may rise to
>1000 nM, while the resting intracellular [Ca++] is only on the order of
>100nM. The removal rate of [Ca++] appears to be crutial to burstors or cell
>firing toniclly.
>But I don't know what the removal rate of [Ca++]... :(
We are calcium imaging (with FURA-2) whilst recording
intracellularly from CA1 cells in rat hippocampal
slices. We induce LTD by a 500 ms intracellular
depolarizing current pulse, which typically causes
10-20 action potentials. This increases resting
calcium from between 20-50nM up to 100-200nM, and this
increased concentration decays back to baseline in about 1000ms.
These values are from soma and proximal apical dendrite, Ca
concentration would be higher if measured for small volumes
close to the membrane etc. Preliminary results are given
in J. Neurophysiol. 1993 vol. 69: 219-229.
Another group (Jaffe, Fisher & Brown) imaging in the
dendritic shaft and spine get a 400-500% increase in
Ca concentration in response to a 500ms current pulse
and this decays back to base in around 5s (J. Neurobiology
1994 vol. 25: 220-223).
Hope this is of some help. Contact me if you need more
info.
Cheers
--
Richard Vickery \ / Our Quest is for meaning,
Physiology, UCL (London) (oVo) but the Meaning IS the quest.
ph. 44-71-387 7050 x3256 ) (
fax 44-71-383 7005 ^ ^ Life's a Hoot!
--
Richard Vickery \ / Our Quest is for meaning,
Physiology, UCL (London) (oVo) but the Meaning IS the quest.
ph. 44-71-387 7050 x3256 ) (
fax 44-71-383 7005 ^ ^ Life's a Hoot!
