|
|
||||||||
Journal of Neurophysiology, Vol 68, Issue 6 2016-2025, Copyright © 1992 by APS
ARTICLES |
J. S. Schweitzer, P. R. Patrylo and F. E. Dudek
Mental Retardation Research Center, University of California, Los Angeles 90024.
1. The dentate gyrus has been proposed to be a gate for entry of neuronal activity into the hippocampus. This function would give it a critical role in the propagation of seizure activity in that region. The hallmark of epileptiform activity in the dentate itself, often referred to as "maximal dentate activation" (MDA), has not been reproduced previously in vitro. 2. With the use of rat hippocampal slices, bath [Ca2+] was decreased, and [K+] was increased concurrently to simulate conditions found during intense neuronal activity in vivo. Both evoked and spontaneous field bursts were observed in the dentate granule cell layer under these conditions. These bursts were similar to MDA, consisting of a prolonged negative shift in extracellular potential with large-amplitude population spikes. 3. In 0.5 mM bath [Ca2+], single stimuli applied to the perforant path could evoke prolonged field bursts in the dentate only when bath [K+] was > or = 9 mM. However, repetitive stimulation (10 Hz) of the perforant path could elicit similar dentate responses when bath [K+] was as low as 5 mM. 4. In 0.5 mM bath [Ca2+], interictal-type bursts appeared spontaneously in CA1 and CA3 when bath [K+] was > or = 5 mM but were lost when [K+] was > 9 mM. Spontaneous seizurelike activity in the dentate required a higher minimum bath [K+] (9 mM) and persisted at [K+] of 11 mM. 5. Stimulation-evoked field bursts in the dentate altered epileptiform activity in CA3. At bath [K+] insufficient to cause spontaneous CA3 bursts, CA3 was activated transiently when prolonged field bursts occurred in the dentate. At higher bath [K+] in which spontaneous CA3 bursts did occur, they were depressed during the dentate bursts. 6. Deletion of Ca2+ from the bath; the addition of 30 microM each of bicuculline methiodide, D,L-2-amino-5-phosphonopentanoate (AP-5), and 6,7-dinitroquinoxaline-2,3-dione (DNQX); or the combination of both manipulations did not block antidromically evoked or spontaneous prolonged field bursts in the dentate. Thus the mechanisms maintaining and propagating these events did not require fast amino acid-mediated synaptic transmission. 7. The concurrent alteration of [K+] and [Ca2+] required to produce prolonged field bursts in the dentate underscores the positive feedback relationship between neuronal excitation and extracellular ionic concentrations, whereas the ability of synaptic stimulation to trigger nonsynaptic seizurelike events such as these prolonged field bursts may be relevant to the transition from interictal to ictal activity in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)
This article has been cited by other articles:
![]() |
Z. Peng and C. R. Houser Temporal Patterns of Fos Expression in the Dentate Gyrus after Spontaneous Seizures in a Mouse Model of Temporal Lobe Epilepsy J. Neurosci., August 3, 2005; 25(31): 7210 - 7220. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Feng and D. M. Durand Decrease in Synaptic Transmission Can Reverse the Propagation Direction of Epileptiform Activity in Hippocampus In Vivo J Neurophysiol, March 1, 2005; 93(3): 1158 - 1164. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Gabriel, M. Njunting, J. K. Pomper, M. Merschhemke, E. R. G. Sanabria, A. Eilers, A. Kivi, M. Zeller, H.-J. Meencke, E. A. Cavalheiro, et al. Stimulus and Potassium-Induced Epileptiform Activity in the Human Dentate Gyrus from Patients with and without Hippocampal Sclerosis J. Neurosci., November 17, 2004; 24(46): 10416 - 10430. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Feng and D. M. Durand Low-Calcium Epileptiform Activity in the Hippocampus In Vivo J Neurophysiol, October 1, 2003; 90(4): 2253 - 2260. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. C. Chattipakorn and L. L. McMahon Strychnine-Sensitive Glycine Receptors Depress Hyperexcitability in Rat Dentate Gyrus J Neurophysiol, March 1, 2003; 89(3): 1339 - 1342. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. C. Stacey and D. M. Durand Noise and Coupling Affect Signal Detection and Bursting in a Simulated Physiological Neural Network J Neurophysiol, November 1, 2002; 88(5): 2598 - 2611. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. T. Finnerty, M. A. Whittington, and J.G.R. Jefferys Altered Dentate Filtering During the Transition to Seizure in the Rat Tetanus Toxin Model of Epilepsy J Neurophysiol, December 1, 2001; 86(6): 2748 - 2753. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z.-Q. Xiong and J. L. Stringer Prolonged Bursts Occur in Normal Calcium in Hippocampal Slices After Raising Excitability and Blocking Synaptic Transmission J Neurophysiol, November 1, 2001; 86(5): 2625 - 2628. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Behr, U. Heinemann, and I. Mody Kindling Induces Transient NMDA Receptor-Mediated Facilitation of High-Frequency Input in the Rat Dentate Gyrus J Neurophysiol, May 1, 2001; 85(5): 2195 - 2202. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. L. Hardison, M. M. Okazaki, and J. V. Nadler Modest Increase in Extracellular Potassium Unmasks Effect of Recurrent Mossy Fiber Growth J Neurophysiol, November 1, 2000; 84(5): 2380 - 2389. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. S. Schweitzer, H. Wang, Z.-Q. Xiong, and J. L. Stringer pH Sensitivity of Non-Synaptic Field Bursts in the Dentate Gyrus J Neurophysiol, August 1, 2000; 84(2): 927 - 933. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. S. Ghai, M. Bikson, and D. M. Durand Effects of Applied Electric Fields on Low-Calcium Epileptiform Activity in the CA1 Region of Rat Hippocampal Slices J Neurophysiol, July 1, 2000; 84(1): 274 - 280. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Barbarosie, J. Louvel, I. Kurcewicz, and M. Avoli CA3-Released Entorhinal Seizures Disclose Dentate Gyrus Epileptogenicity and Unmask a Temporoammonic Pathway J Neurophysiol, March 1, 2000; 83(3): 1115 - 1124. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z.-Q. Xiong and J. L. Stringer Sodium Pump Activity, Not Glial Spatial Buffering, Clears Potassium After Epileptiform Activity Induced in the Dentate Gyrus J Neurophysiol, March 1, 2000; 83(3): 1443 - 1451. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z.-Q. Xiong, P. Saggau, and J. L. Stringer Activity-Dependent Intracellular Acidification Correlates with the Duration of Seizure Activity J. Neurosci., February 15, 2000; 20(4): 1290 - 1296. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Demir, L. B. Haberly, and M. B. Jackson Sustained Plateau Activity Precedes and Can Generate Ictal-Like Discharges in Low-Cl- Medium in Slices from Rat Piriform Cortex J. Neurosci., December 15, 1999; 19(24): 10738 - 10746. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z.-Q. Xiong and J. L. Stringer Cesium Induces Spontaneous Epileptiform Activity Without Changing Extracellular Potassium Regulation in Rat Hippocampus J Neurophysiol, December 1, 1999; 82(6): 3339 - 3346. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Molnar and J. V. Nadler Mossy Fiber-Granule Cell Synapses in the Normal and Epileptic Rat Dentate Gyrus Studied With Minimal Laser Photostimulation J Neurophysiol, October 1, 1999; 82(4): 1883 - 1894. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. A. Basarsky, D. Feighan, and B. A. MacVicar Glutamate Release through Volume-Activated Channels during Spreading Depression J. Neurosci., August 1, 1999; 19(15): 6439 - 6445. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. M. Okazaki, P. Molnar, and J. V. Nadler Recurrent Mossy Fiber Pathway in Rat Dentate Gyrus: Synaptic Currents Evoked in Presence and Absence of Seizure-Induced Growth J Neurophysiol, April 1, 1999; 81(4): 1645 - 1660. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. S. Buckmaster and F. E. Dudek In Vivo Intracellular Analysis of Granule Cell Axon Reorganization in Epileptic Rats J Neurophysiol, February 1, 1999; 81(2): 712 - 721. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Pan and J. L. Stringer Role of Potassium and Calcium in the Generation of Cellular Bursts in the Dentate Gyrus J Neurophysiol, May 1, 1997; 77(5): 2293 - 2299. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Bragin, M. Penttonen, and G. Buzsaki Termination of Epileptic Afterdischarge in the Hippocampus J. Neurosci., April 1, 1997; 17(7): 2567 - 2579. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |