Post-ischemic Time-dependent Activity Changes of Hippocampal CA1 cells of the Mongolian Gerbils.
- Author:
Moo Ho WON
1
;
Hyung Cheul SHIN
Author Information
1. Department of Physiology, College of Medicine, Hallym University, Chuncheon 200-702, Korea. hcshin@hallym.ac.kr
- Publication Type:Original Article
- Keywords:
Transient ischemia;
Hippocampal CA1 cells;
Temporal activity change;
Correlative firing
- MeSH:
Animals;
Cell Death;
Depression;
Electrodes;
Fires;
Gerbillinae*;
Hippocampus;
Ischemia;
Neurons;
Reference Values;
Viola
- From:The Korean Journal of Physiology and Pharmacology
2007;11(6):247-251
- CountryRepublic of Korea
- Language:English
-
Abstract:
Changes of single unit activity of CA1 hippocampus region were investigated in anesthetized Mongolian gerbils for six days following transient ischemia. Ischemia was produced immediately before the implantation of micro-wire recording electrodes. In control animals receiving pseudo-ischemic surgery, neither spontaneous neuronal activities (5.70+/-0.4 Hz) nor the number of recorded neurons per animal changed significantly for six days. Correlative firings among simultaneously recorded neurons were weak (correlation coefficient >0.6) in the control animals. Animals subjected to ischemia exhibited a significant elevation of neural firing at post-ischemic 12 hr (9.95+/-0.9 Hz) and day 1 (8.48+/-0.8 Hz), but a significant depression of activity at post-ischemic day 6 (1.84+/-0.3 Hz) when compared to the activities of non-ischemic control animal. Ischemia significantly (correlation coefficient <0.6) increased correlative firings among simultaneously recorded neurons, which were prominent especially during post-ischemic days 1, 2 and 6. Although the numbers of spontaneously active neurons recorded from control group varied within normal range during the experimental period, those from ischemic group changed in post-ischemic time-dependent manner. Temporal changes of the number of cells recorded per animal between control group and ischemic group were also significantly different (p = 0.0084, t = 3.271, df = 10). Cresyl violet staining indicated significant loss of CA1 cells at post-ischemic day 7. Overall, we showed post-ischemic time-dependent, differential changes of three characteristics, including spontaneous activity, network relationship and excitability of CA1 cells, suggesting sustained neural functions. Thus, histological observation of CA1 cell death till post-ischemic day 7 may not represent actual neuronal death.
