|
|
||||||||

Anaesthesia Research Department, McGill University, Montréal, Canada.
1. During whole-cell recordings from CA1 neurons of rat brain slices with electrodes containing only KMeSO4 and Hepes, brief anoxia (2-3 min) consistently evoked a hyperpolarization (delta V approximately 14 mV) and reduction in input resistance (delta R approximately -20%). 2. As in previous intracellular recordings, Dantrolene sodium (10 microM) suppressed the anoxic delta V and delta R, confirming the release of internal Ca2+ is a major component of the anoxic response. 3. To identify the relevant intracellular Ca2+ store, other blockers of Ca2+ release were applied either externally (in the bath) or internally, by addition to the contents of the recording electrode. 4. The anoxic hyperpolarization was abolished or much reduced by heparin (10-20 micrograms ml-1, internal), thapsigargin (10 microM, external), Ruthenium Red (50 microM, internal) and external procaine (0.5-2 mM), but not by internal procaine (0.5-1 mM) or ryanodine (10 microM, external). 5. The anoxic fall in resistance was also abolished or reduced by heparin, thapsigargin and external procaine, but not by ryanodine, internal procaine or Ruthenium Red. 6. In addition, external procaine (0.5-2 mM) eliminated the early (transient) depolarization and reduced the post-anoxic hyperpolarization by 60 +/- 22%. 7. None of these agents consistently changed the resting potential, but the input resistance was significantly increased by Dantrolene and external procaine. 8. In view of the marked effects of heparin and thapsigargin, but not ryanodine and internal procaine, we conclude that the anoxic response seen in such whole-cell recordings is initiated predominantly by Ca2+ release from an internal store that is InsP3 sensitive rather than Ca2+ sensitive. 9. Comparable but less pronounced effects of external procaine were seen during intracellular recordings with 3 M KCl-containing electrodes. The dose-dependent suppression of various features of the anoxic response by external procaine (EC50 approximately 0.2 mM) is presumed to be mediated by a superficial membrane trigger or modulating site.
This article has been cited by other articles:
![]() |
J. C. Gant, M. M. Sama, P. W. Landfield, and O. Thibault Early and simultaneous emergence of multiple hippocampal biomarkers of aging is mediated by Ca2+-induced Ca2+ release. J. Neurosci., March 29, 2006; 26(13): 3482 - 3490. [Abstract] [Full Text] [PDF] |
||||
![]() |
M.-K. Sun, H. Xu, and D. L. Alkon Pharmacological Protection of Synaptic Function, Spatial Learning, and Memory from Transient Hypoxia in Rats J. Pharmacol. Exp. Ther., February 1, 2002; 300(2): 408 - 416. [Abstract] [Full Text] [PDF] |
||||
![]() |
X. X. Chi and Z. C. Xu Differential Changes of Potassium Currents in CA1 Pyramidal Neurons After Transient Forebrain Ischemia J Neurophysiol, December 1, 2000; 84(6): 2834 - 2843. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. Vicario, A. Obeso, A. Rocher, J. R. Lopez-Lopez, and C. Gonzalez Intracellular Ca2+ stores in chemoreceptor cells of the rabbit carotid body: significance for chemoreception Am J Physiol Cell Physiol, July 1, 2000; 279(1): C51 - C61. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Wang, G. Chambers, J. E. Cottrell, and I. S. Kass Differential Fall in ATP Accounts for Effects of Temperature on Hypoxic Damage in Rat Hippocampal Slices J Neurophysiol, June 1, 2000; 83(6): 3462 - 3472. [Abstract] [Full Text] [PDF] |
||||
![]() |
G.-F. Tian and A. J. Baker Glycolysis Prevents Anoxia-Induced Synaptic Transmission Damage in Rat Hippocampal Slices J Neurophysiol, April 1, 2000; 83(4): 1830 - 1839. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Tanabe, M. Mori, B. H. Gahwiler, and U. Gerber Apamin-Sensitive Conductance Mediates the K+ Current Response During Chemical Ischemia in CA3 Pyramidal Cells J Neurophysiol, December 1, 1999; 82(6): 2876 - 2882. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Wang, K. M. Raley-Susman, J. Wang, G. Chambers, J. E. Cottrell, I. S. Kass, and D. J. Cole Thiopental Attenuates Hypoxic Changes of Electrophysiology, Biochemistry, and Morphology in Rat Hippocampal Slice CA1 Pyramidal Cells • Editorial Comment Stroke, November 1, 1999; 30 (11): 2400 - 2407. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Ouanonou, Y. Zhang, and L. Zhang Changes in the Calcium Dependence of Glutamate Transmission in the Hippocampal CA1 Region After Brief Hypoxia-Hypoglycemia J Neurophysiol, September 1, 1999; 82(3): 1147 - 1155. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. M. Sandler and J.-G. Barbara Calcium-Induced Calcium Release Contributes to Action Potential-Evoked Calcium Transients in Hippocampal CA1 Pyramidal Neurons J. Neurosci., June 1, 1999; 19(11): 4325 - 4336. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Erdemli, Y. Z. Xu, and K. Krnjevic Potassium Conductance Causing Hyperpolarization of CA1 Hippocampal Neurons During Hypoxia J Neurophysiol, November 1, 1998; 80(5): 2378 - 2390. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Erdemli and V. Crunelli Response of Thalamocortical Neurons to Hypoxia: A Whole-Cell Patch-Clamp Study J. Neurosci., July 15, 1998; 18(14): 5212 - 5224. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Inoue and I. Imanaga Activation of Ca2+-dependent K+ channels by cyanide in guinea pig adrenal chromaffin cells Am J Physiol Cell Physiol, January 1, 1998; 274(1): C105 - C111. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Leppanen and P. K. Stys Ion Transport and Membrane Potential in CNS Myelinated Axons II. Effects of Metabolic Inhibition J Neurophysiol, October 1, 1997; 78(4): 2095 - 2107. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. J. Zhu Adenosine Release Mediates Cyanide-Induced Suppression of CA1 Neuronal Activity J. Neurosci., April 1, 1997; 17(7): 2355 - 2364. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Fujimura, E. Tanaka, S. Yamamoto, M. Shigemori, and H. Higashi Contribution of ATP-Sensitive Potassium Channels to Hypoxic Hyperpolarization in Rat Hippocampal CA1 Neurons In Vitro J Neurophysiol, January 1, 1997; 77(1): 378 - 385. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Yamamoto, E. Tanaka, and H. Higashi Mediation by Intracellular Calcium-Dependent Signals of Hypoxic Hyperpolarization in Rat Hippocampal CA1 Neurons In Vitro J Neurophysiol, January 1, 1997; 77(1): 386 - 392. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |