The overall goal of this proposal is to understand the neural regulation of certain inhibitory events in the brain, in the belief that this approach will lead to methods that therapeutically enhance neuronal inhibition, and that therefore suppress the abnormal neuronal discharges of epilepsy. To this end, intracellular recording methods will be applied to an in vitro model of mammalian cerebral cortex: the hippocampal slice. The specific focus of this proposal is upon a slow inhibitory event that follows synaptic stimulation of neurons of hippocampus, and probably neurons in many other brain regions as well. We have found that this event is not due to GABAA receptors that are coupled to chloride channels, as is the better understood 'early' inhibitory postsynaptic potential. Instead, it is insensitive to the action of GABAA antagonists, and depends upon an increased membrane conductance to potassium, rather than chloride.
The specific aims of this proposal are 1) to characterize the extent to which transmembrane voltage regulates this late hyperpolarization, 2) to test the hypothesis that increases or decreases in cyclic AMP modulate or control the late hyperpolarization, and 3) to identify transmitter candidates that serve as either the transmitters for, or modulators of, this response.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS021713-03
Application #
3403154
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1985-07-01
Project End
1988-06-30
Budget Start
1987-07-01
Budget End
1988-06-30
Support Year
3
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
Al-Dahan, M I; Jalilian Tehrani, M H; Thalmann, R H (1999) Regulation of cyclic AMP level by progesterone in ovariectomized rat neocortex. Brain Res 824:258-66
al-Dahan, M I; Thalmann, R H (1996) Progesterone regulates gamma-aminobutyric acid B (GABAB) receptors in the neocortex of female rats. Brain Res 727:40-8
al-Dahan, M I; Jalilian Tehrani, M H; Thalmann, R H (1994) Regulation of gamma-aminobutyric acidB (GABAB) receptors in cerebral cortex during the estrous cycle. Brain Res 640:33-9
al-Dahan, M I; Tehrani, M H; Thalmann, R H (1990) Effect of 2-hydroxy-saclofen, an antagonist of GABAB action, upon the binding of baclofen and other receptor ligands in rat cerebrum. Brain Res 526:308-12
Al-Dahan, M I; Thalmann, R H (1989) Effects of dihydropyridine calcium channel ligands on rat brain gamma-aminobutyric acidB receptors. J Neurochem 53:982-5
al-Dahan, M I; Thalmann, R H (1989) Effect of guanosine 5'-O-(3-thiotriphosphate) and calcium on gamma-aminobutyric acidB binding as a function of postnatal development. J Neurochem 52:313-6
Thalmann, R H (1988) Evidence that guanosine triphosphate (GTP)-binding proteins control a synaptic response in brain: effect of pertussis toxin and GTP gamma S on the late inhibitory postsynaptic potential of hippocampal CA3 neurons. J Neurosci 8:4589-602
Thalmann, R H (1988) Blockade of a late inhibitory postsynaptic potential in hippocampal CA3 neurons in vitro reveals a late depolarizing potential that is augmented by pentobarbital. Neurosci Lett 95:155-60
Thalmann, R H (1987) Pertussis toxin blocks a late inhibitory postsynaptic potential in hippocampal CA3 neurons. Neurosci Lett 82:41-6
Hablitz, J J; Thalmann, R H (1987) Conductance changes underlying a late synaptic hyperpolarization in hippocampal CA3 neurons. J Neurophysiol 58:160-79

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