TESKEY GC, ATKINSON BG, CAIN DP
MOLECULAR BRAIN RESEARCH
11: (1) 1-10 AUG 1991
Kindling is a permanent form of brain change that results from repeated elicitation of epileptiform neural activity. c-fos has been proposed as the gene responsible for turning on molecular events that might underlie the long-term neural changes that occur during kindling. This study investigated the enhancement of c-fos levels following kindled seizures and the role of c-fos in the plastic changes underlying kindling. Male hooded rats were electrically kindled in the amygdala and the resulting c-fos and c-Ha-ras gene expression was quantified using Northern blot hybridization analysis. The results indicated that c-fos was constitutively expressed in forebrain and cerebellum, and that basal levels of c-fos were equivalent in naive and in fully kindled rats that have been seizure-free for 3 weeks. Following an amygdala-piriform kindled seizure there was a massive and transient increase in c-fos levels throughout forebrain and cerebellum. Although enhanced c-fos levels were correlated with afterdischarge (AD) duration in the kindled site, enhanced c-fos levels were also observed in the amygdala-piriform contralateral to the kindled site, and the enhancement did not depend on the occurrence of AD in the contralateral amygdala-piriform. Furthermore, electrical stimulations not resulting in AD as well as other forms of control stimulation also increased c-fos levels. We conclude that c-fos was expressed simply as a consequence of neural activity and not exclusively due to the specific neural activity or underlying plastic change required for kindling. This does not preclude a role for c-fos in the long-term response to external stimuli, but it does suggest that c-fos is not the crucial 'master switch' in turning on a molecular program that might underlie kindling.
ONCOGENE, C-FOS, C-RAS, KINDLING, AMYGDALA, RAT, NEURAL PLASTICITY
NERVE GROWTH-FACTOR, LONG-TERM POTENTIATION, IMMEDIATE-EARLY GENES, SARCOMA-VIRUS GENOME, MESSENGER-RNA, MOLECULAR-CLONING, MAMMALIAN NEURONS, LIMBIC FOREBRAIN, SEIZURE ACTIVITY, PYRIFORM CORTEX
UNIV WESTERN ONTARIO, DEPT PSYCHOL, LONDON N6A 3K7, ONTARIO, CANADA.
UNIV WESTERN ONTARIO, DEPT ZOOL, LONDON N6A 3K7, ONTARIO, CANADA.
ELSEVIER SCIENCE BV, AMSTERDAM