Document Detail

Are differences in dorsal hippocampal kindling related to amygdala-piriform area excitability?
MedLine Citation:
PMID:  8449179     Owner:  NLM     Status:  MEDLINE    
It has been suggested that several structures associated with the amygdala-piriform (A-P) area are important, if not critical, for convulsive generalization of limbic seizures. In experiment 1, when examining the development of convulsive seizures kindled from the dorsal hippocampus (cornus ammonis; DH), a broad range of kindling rates was observed. Independent of electrode location within the hippocampus, kindling rates were correlated positively with both local and, more dramatically, distant excitability (measured by the duration of the primary and secondary hippocampal afterdischarges, respectively) at all stages of epileptogenesis. Because kindling rates were bimodally distributed, we bisected the distribution into 'faster' and 'slower' kindling rats. Here we examined the magnitude of both electrophysiological and behavioral differences between 'faster' and 'slower' rats and their changes over time. The 'faster' rats had longer primary and secondary afterdischarge (AD) durations than 'slower' rats throughout all stages of kindling. With the appearance of generalized convulsions, the 'faster' rats showed longer latencies to clonus onset, with longer clonus and AD durations than 'slower' rats. Also, the generalized convulsions of 'faster' rats appeared during a much enlarged secondary AD period, while 'slower' rats convulsed during primary AD. In both groups, convulsions were invariably associated with increased discharge in A-P associated structures. We interpreted the differences between 'faster' and 'slower' DH rats to reflect genetic differences in excitability in both local and A-P associated structures. If the DH kindling profile of the 'faster' rats differed from 'slower' rats largely because of naturally greater excitability in A-P associated structures, then experimentally increased excitability in those structures (via amygdala kindling) in a random sample of rats should duplicate much of the 'faster' DH kindling profile. In experiment 2, this outcome was observed. In conclusion, we suggest that either natural or induced differences in the excitability of A-P associated structures affect both the genesis and the profile of convulsive generalization of limbic kindled seizures.
D C McIntyre; M E Kelly
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Epilepsy research     Volume:  14     ISSN:  0920-1211     ISO Abbreviation:  Epilepsy Res.     Publication Date:  1993 Jan 
Date Detail:
Created Date:  1993-04-14     Completed Date:  1993-04-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8703089     Medline TA:  Epilepsy Res     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  49-61     Citation Subset:  IM    
Department of Psychology, Carleton University, Ottawa, Ont., Canada.
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MeSH Terms
Amygdala / physiology*
Cerebral Cortex / physiology*
Electrodes, Implanted
Hippocampus / anatomy & histology,  physiology*
Kindling, Neurologic / physiology*
Olfactory Bulb / physiology
Seizures / genetics,  pathology,  physiopathology

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