Reports indicate that the amygdala, a limbic structure, is intimately involved in cases of intractable temporal lobe epilepsy. In this proposal, a model of human temporal lobe epilepsy will be used, namely, kindling using the amygdala as the focus. The amygdala focus resembles human temporal lobe epilepsy in resistance to antiepileptic drugs and in the behavioral characteristics of the kindled seizure. To promote an appropriate therapy it is essential to understand the etiology of temporal lobe epilepsy. The long term goals of this research are to elucidate the membrane or cellular mechanisms which underlie the kindling phenomenon in the amygdala and ultimately, through physiological and pharmacological analyses of these mechanisms, to suggest a rational basis for the pharmacological treatment of intractable temporal lobe epilepsy. Intracellular recordings from an in vitro rat brain slice preparation of the amygdaloid complex will be used to address three specific aims: I. to analyze and characterize in vitro the intrinsic electrophysiological properties of individual neurons in the basolateral nuclei at the focus (implanted side) of the amygdaloid complex as a result of kindling in vivo in the basolateral nucleus of the rat. The animals will be tested 28 days after reaching stage 5 of kindling. Changes in the membrane properties would refect alterations in ionic currents and channels underlying those parameters. The contralateral amygdala will also be analyzed. II. To compare the synaptic responses of basolateral cells on the contralateral side to stimulation of afferent input from the stria terminalis and the amygdalofugal pathway (in the area of the median forebrain bundle) in control and kindled animals and to assess the neurotransmitter systems which may be altered as a result of kindling. III. Because recent data suggest kindling may affect individual brain nuclei in different ways, the electrophysiological changes that occur in the ipsilateral central nucleus will be compared with those that occur in the basolateral nuclei. Results obtained from these experiments will provide essential information about the kindling phenomenon. This information will be directly applicable to our understanding of epileptogenesis involving the amygdala in human complex partial seizures.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS024643-03
Application #
3409421
Study Section
Neurology A Study Section (NEUA)
Project Start
1988-02-01
Project End
1992-11-30
Budget Start
1990-02-01
Budget End
1992-11-30
Support Year
3
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Type
Schools of Medicine
DUNS #
041367053
City
Galveston
State
TX
Country
United States
Zip Code
77555
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Keele, N B; Zinebi, F; Neugebauer, V et al. (2000) Epileptogenesis up-regulates metabotropic glutamate receptor activation of sodium-calcium exchange current in the amygdala. J Neurophysiol 83:2458-62
Keele, N B; Neugebauer, V; Shinnick-Gallagher, P (1999) Differential effects of metabotropic glutamate receptor antagonists on bursting activity in the amygdala. J Neurophysiol 81:2056-65
Yu, B; Shinnick-Gallagher, P (1998) Corticotropin-releasing factor increases dihydropyridine- and neurotoxin-resistant calcium currents in neurons of the central amygdala. J Pharmacol Exp Ther 284:170-9
Neugebauer, V; Keele, N B; Shinnick-Gallagher, P (1997) Epileptogenesis in vivo enhances the sensitivity of inhibitory presynaptic metabotropic glutamate receptors in basolateral amygdala neurons in vitro. J Neurosci 17:983-95
Keele, N B; Arvanov, V L; Shinnick-Gallagher, P (1997) Quisqualate-preferring metabotropic glutamate receptor activates Na(+)-Ca2+ exchange in rat basolateral amygdala neurones. J Physiol 499 ( Pt 1):87-104
Keele, N B; Arvanov, V; Holmes, K et al. (1995) Agonist action of (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG) in the amygdala. Neuroreport 6:1058-62
Arvanov, V L; Holmes, K H; Keele, N B et al. (1995) The functional role of metabotropic glutamate receptors in epileptiform activity induced by 4-aminopyridine in the rat amygdala slice. Brain Res 669:140-4
Gallagher, J P; Zheng, F; Hasuo, H et al. (1995) Activities of neurons within the rat dorsolateral septal nucleus (DLSN). Prog Neurobiol 45:373-95
Rainnie, D G; Holmes, K H; Shinnick-Gallagher, P (1994) Activation of postsynaptic metabotropic glutamate receptors by trans-ACPD hyperpolarizes neurons of the basolateral amygdala. J Neurosci 14:7208-20

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