Physiology and Pharmacology
Physiol Pharmacol
Medical Sciences
http://ppj.phypha.ir
32
journal32
24765236
24765244
10.61186/phypha
(previous ISSN: 17350581)
en
jalali
1378
1
1
gregorian
1999
4
1
3
1
online
1
fulltext
en
Effects of visual deprivation on epileptic activity in mature rat visual cortex
Experimental research article
Experimental research article
<p> Effects of visual deprivation on the induction of epileptiform activity were studied in layer II/III of mature rat primary visual cortex. Field potentials were evoked by stimulation of layer IV in slices from control and dark-reared (OR) rats. Picrotoxin (PTX)-induced epileptic activity was characterized by spontaneous and evoked epileptic field potentials (EFPs). The results showed that OR slices demonstrate greater susceptibility for induction of spontaneous EFP. PTX-induced changes in the properties of evoked field potentials also showed higher tendency of OR animals to epileptogenesis. In both groups, field potentials are consisted of pEPSP<sub>1</sub> (population excitatory post-synaptic potential 1, i.e. first negativity) and pEPSP<sub>2</sub> (second negativity). PTX significantly increased the amplitude and duration of pEPSP<sub>2</sub>, but it had no significant effect on pEPSP<sub>1</sub>. PTX-induced changes in characteristics of pEPSP<sub>2</sub> were significantly higher in OR slices. It is concluded that visual deprivation causes lasting changes in layer II/III of visual cortex that retain in slices and predispose this area for PTX-induced epileptiform activity. </p>
Brain Slice; Neocortex; Epileptic field potential; Dark-rearing; Picrotoxin
59
65
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