Shahabi P, Gorji A, Fathollahi Y, Janahmadi M, Mirnajafi-zade J, Arabkheradmand J et al . Electrophysiological characteristics of hippocampal CA1 neurons after spreading depression-triggered epileptic activity in brain slices. Physiol Pharmacol 2011; 15 (1) :1-15
URL:
http://ppj.phypha.ir/article-1-683-en.html
Abstract: (17061 Views)
Introduction: A close link between spreading depression (SD) and several neurological diseases such as epilepsy
could be demonstrated in many experimental studies. Epilepsy is among the most common brain disorders. Despite a
large number of investigations, its mechanisms have not been yet well elucidated. Hippocampus is one of the important
structures involved in seizures. The aim of this study is to get an insight into the patho-physiological processes induced
by SD that lead to the generation of epileptiform field potentials.
Methods: The horizontal amygdala-hippocampus-neocortex slices of rat brain in which SD was induced by KCl
application in each brain structure were used. Following GABAA receptor antagonist bicuculline superfusion (1.25
μmol/L, for 45 min), SD induced epileptic activity in all tested slices was monitored.
Results: The induction of SD in the hippocampus resulted in interictal and ictal epileptiform field potentials and
intracellular paroxysmal depolarization shifts (PDS). After SD, RMP slightly depolarized and the threshold of AP
decreased, while the frequency of AP significantly increased. Amplitude of depolarization and also amplitude of
discharges were also significantly increased. ISI significantly decreased and the most of neurons shifted from FA to SA
indicating an enhanced excitability.
Conclusion: SD may cause pathological changes in brain structures such as increased excitation and/or decreased
inhibition. Propagation of SD over epileptogenic areas may trigger seizure attacks in some patients and our findings
provide evidence on the role of SD in temporal lobe epilepsy.