| 1985 — 1990 |
Leslie, Steven W |
K01Activity Code Description:
For support of a scientist, committed to research, in need of both advanced research training and additional experience. K02Activity Code Description:
Undocumented code - click on the grant title for more information. R01Activity Code Description:
To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Membrane Tolerance to Ethanol and Barbiturates @ University of Texas Austin
The objective of this investigation will be to determine the central nervous system membrane alterations produced by acute and chronic ethanol and barbiturate administratiaon which occur in a correlative manner to intoxication and the development of tolerance and physical dependence. Specifically, male, Sprague-Dawley rats will be separated into the following treatment groups: control, pairfed control, tolerant, withdrawn and recovered. Whole brains and brain regions (cerebral cortex, cerebellu, brain stem, hypothalamus, midbrain and corpus striatum) will be removed from animals in each treatment group and synaptosomes, synaptosomal plasma membranes (SPM) mitochondria and microsomes will be isolated by ultracentrifugation. Synaptosomes from each treatment group and each brain region will be analyzed for 1) cross-tolerance to barbiturate-and ethanol-induced inhibition of 45Ca++ transport produced by acidic membrane lipids after acute and/or chronic administration of these drugs. In addition, the acute and chronic effects of ethanol and barbiturates will be examined on ATP-dependent 45Ca++ uptake and fatty acid composition of the subcellular organelles listed above. The overall objective will be to determine cellular mechanisms involved in the production of sedation and the deeelopment of tolerance and physical dependence.
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| 1987 — 1998 |
Leslie, Steven W |
T32Activity Code Description:
To enable institutions to make National Research Service Awards to individuals selected by them for predoctoral and postdoctoral research training in specified shortage areas. |
Neurochemical and Behavioral Correlates of Etoh Effects @ University of Texas Austin |
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| 1989 — 1991 |
Leslie, Steven W |
R01Activity Code Description:
To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Aging and Alcohol On Neuronal Calcium Metabolism @ University of Texas Austin
The overall aim of this project is to characterize the relationships between aging, acute and chronic ethanol administration and altered neuronal calcium transport and calcium-dependent stimulus-secretion coupling. Our general hypothesis is that both ethanol administration and aging result in a reduction in calcium entry through calcium channels into neurons and a change in calcium metabolism in the neuronal cytosol. In combination, ethanol and aging may facilitate the occurrence of decrements in calcium channel function and exacerbate the changes in intracellular calcium homeostasis. Studies are designed to characterize the influence of acute and chronic alcohol on the kinetics of voltage-dependent calcium channels in synaptosomes and synaptoneurosomes isolated from young versus old male, Fischer 344 rats. Experiments will be conducted in seven brain regions(cerebral cortex, cerebellum, brain stem, midbrain, hypothalamus, hippocampus and striatum) known to vary in sensitivity to aging and alcohol. these experiments will examine simultaneously (and in the sam samples as the calcium experiments) endogenous dopamine and norepinephrine release to examine the influence of ethanol and aging on stimulus-secretion coupling processes. Studies will be conducted to determine the effects of age and acute and chronic alcohol on dihydropyridine-sensitive calcium channels in brain regional synaptosomes and synaptoneurosomes. The brain regions to be studied will be the same seven as described above. These brain regions differ in the distribution of dihdropyridine binding sites. Finally, studies will be conducted to characterize the effects of acute and chronic ethanol administration on free, cytosolic calcium concentration of synaptosomes and synaptoneurosomes in young versus old rats. These studies will be conducted on the seven brain regions described above using the intracellular calcium indicator Fura-2.
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| 1991 — 1999 |
Leslie, Steven W |
R01Activity Code Description:
To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. R37Activity Code Description:
To provide long-term grant support to investigators whose research competence and productivity are distinctly superior and who are highly likely to continue to perform in an outstanding manner. Investigators may not apply for a MERIT award. Program staff and/or members of the cognizant National Advisory Council/Board will identify candidates for the MERIT award during the course of review of competing research grant applications prepared and submitted in accordance with regular PHS requirements. |
Ethanol On Calcium Channels and Nmda Receptors @ University of Texas Austin
This competing continuation project will continue to examine the effects of acute and chronic ethanol administration on calcium entry into neuronal preparations. The focus of the experiments will be to study the effects of ethanol on NMDA-stimulated calcium entry into dissociated brain cells. Studies will also be conducted on dihydropyridine-(L-type) and w-conotoxin- sensitive (N and L type) calcium channels and their interactions with NMDA receptors. NMDA-stimulated glutamate receptors in the brain appear to be involved in many important processes such as neuronal development, neuronal toxicity and learning and memory. Recent studies in our and other laboratories have shown that NMDA receptor-mediated processes in the brain are highly sensitive to inhibition by ethanol. The studies described in this application will characterize the sensitivity of NMDA-stimulated calcium entry into dissociated brain cells from brain regions known to have high, intermediate and low densities of NMDA receptors. Furthermore, mechanisms of ethanol's inhibitory effects on the NMDA receptor will be determined by studying the role of key modulatory sites (glycine co-agonist site, PCP-inhibitory site, Mg++ inhibitory site and the competitive receptor site) in activating NMDA function (by studying calcium entry) and receptor binding in the presence and absence of ethanol. Recent evidence suggests that there may be links between neuronal abnormalities associated with fetal alcohol exposure and alterations in number or function of NMDA receptors; thus, studies will be conducted to examine the effects of fetal alcohol exposure on NMDA-stimulated calcium entry into isolated dissociated neurons. Receptor binding studies will also be conducted on brain membranes isolated from fetal alcohol exposed rat pups to study its influence on NMDA-receptor modulation. Finally, studies will be conducted to examine the effects of chronic ethanol exposure in adult rats on NMDA- receptor modulation.
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| 1992 — 1996 |
Leslie, Steven W |
R01Activity Code Description:
To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Ethanol and Glutathione On Nmda Receptor Function @ University of Texas Austin
The NMDA-stimulated glutamate receptor Subtype in the brain appears to be involved in many important neuronal processes such as neuronal development, neuronal toxicity and learning and memory. Studies in our and other laboratories have shown that NMDA-receptor mediated processes in the brain are highly sensitive to inhibition by ethanol. Recent work in my laboratories has shown that glutathione (gamma-glutamylcysteinylglycine) stimulates NMDA receptors in an apparent competitive manner to enhance calcium entry through NMDA-stimulated ion channels. Glutathione is found in high concentrations in the brain, particularly high in glial cells. Recent work has shown that glutathione is released from glial cells in a robust manner. Taken together with recent results from my laboratories, the evidence suggests that glutathione (released from glial cells) may activate and possibly regulate NMDA receptor function. The overall objective of the proposed research will be to characterize the interactions of glutathione on NMDA receptor function and to determine the influence of acute and chronic alcohol exposure and prenatal ethanol exposure on the synthesis and release of glutathione and to study the influence of acute and chronic ethanol and prenatal ethanol exposure on glutathione interactions with NMDA receptors. Initially, studies will be conducted to characterize the effects of acute and chronic ethanol and fetal ethanol exposure on the brain concentrations and turnover of reduced (GSH) and oxidized (GSSG) glutathione. Brain regions to be studied will be those with high (cerebellum, cerebral cortex, hippocampus), intermediate (striatum) and low (pons-medulla) densities of NMDA-receptors. Studies are also designed to determine the effects of ethanol on the interactions of glutathione (GSH and GSSG) added in vitro on calcium entry through NMDA-stimulated channels in dissociated neurons. Experiments will also be carried out to demonstrate the mechanistic effects of ethanol in which receptor binding studies will be conducted on membranes from newborn and adult brain regions. The effects of invitro ethanol (5 - 100 mM) and chronic ethanol and its interactions with glutathione will be Studied. Experiments will be conducted on the effects of ethanol and glutathione on the Kd and Bmax for 3H-CPP (NMDA competitive site), 3H-glycine (co-agonist site), and H-MK-801 (allosteric, channel inhibitory PCP site) binding. Finally, studies are designed to characterize the effects of chronic ethanol administration to pregnant, female rats on the glutathione/NMDA-receptor interactions in dissociated neurons from newborn rat pups. These studies will address the question of the possible role that glutamate containing peptides may play in fetal abnormalities after maternal ethanol exposure.
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| 1994 — 1995 |
Leslie, Steven W |
R37Activity Code Description:
To provide long-term grant support to investigators whose research competence and productivity are distinctly superior and who are highly likely to continue to perform in an outstanding manner. Investigators may not apply for a MERIT award. Program staff and/or members of the cognizant National Advisory Council/Board will identify candidates for the MERIT award during the course of review of competing research grant applications prepared and submitted in accordance with regular PHS requirements. |
Ethanol Effects On Calcium Channels and Nmda Receptors @ University of Texas Austin
This competing continuation project will continue to examine the effects of acute and chronic ethanol administration on calcium entry into neuronal preparations. The focus of the experiments will be to study the effects of ethanol on NMDA-stimulated calcium entry into dissociated brain cells. Studies will also be conducted on dihydropyridine-(L-type) and w-conotoxin- sensitive (N and L type) calcium channels and their interactions with NMDA receptors. NMDA-stimulated glutamate receptors in the brain appear to be involved in many important processes such as neuronal development, neuronal toxicity and learning and memory. Recent studies in our and other laboratories have shown that NMDA receptor-mediated processes in the brain are highly sensitive to inhibition by ethanol. The studies described in this application will characterize the sensitivity of NMDA-stimulated calcium entry into dissociated brain cells from brain regions known to have high, intermediate and low densities of NMDA receptors. Furthermore, mechanisms of ethanol's inhibitory effects on the NMDA receptor will be determined by studying the role of key modulatory sites (glycine co-agonist site, PCP-inhibitory site, Mg++ inhibitory site and the competitive receptor site) in activating NMDA function (by studying calcium entry) and receptor binding in the presence and absence of ethanol. Recent evidence suggests that there may be links between neuronal abnormalities associated with fetal alcohol exposure and alterations in number or function of NMDA receptors; thus, studies will be conducted to examine the effects of fetal alcohol exposure on NMDA-stimulated calcium entry into isolated dissociated neurons. Receptor binding studies will also be conducted on brain membranes isolated from fetal alcohol exposed rat pups to study its influence on NMDA-receptor modulation. Finally, studies will be conducted to examine the effects of chronic ethanol exposure in adult rats on NMDA- receptor modulation.
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| 1999 — 2003 |
Leslie, Steven W |
R01Activity Code Description:
To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Moderate Ethanol Prenatally On Nmda Phosphorylation @ University of Texas Austin
Studies in our laboratory and by others indicate that prenatal and early postnatal ethanol exposure results in a significant reduction of NMDA receptor function and number. NMDA receptors are linked with important aspects of brain development and learning and memory. Ethanol-related deficits in NMDA function, therefore, may be of key importance not only in the severe cognitive and behavioral deficiencies of fetal alcohol syndrome (FAS) but also in alcohol-related neurodevelopmental disorders (ARND) typically expressed as behavioral symptoms associated with fetal alcohol effects (FAE). We have recently found that decreases in NMDA receptor function resulting from prenatal ethanol exposure in rats are accompanied by reductions in some, but not all, of the subunits comprising the NMDA receptor complex. NMDAR2A and NMDAR2B subunits are significantly reduced, while the NMDAR1 subunit is unaffected. Studies conducted thus far have examined the effects of high doses of ethanol prenatally and postnatally on NMDA receptor function and subunit levels. Studies proposed in specific aims 1 through 4 are designed to determine the dose-response relationships of prenatal ethanol treatment on 1) functional measures of NMDA receptor activation using fura-2 loaded dissociated neurons and H-MK801 binding, 2) NMDAR1 and NMDAR2 subunit protein (Western blot analysis) and messenger RNA levels (RNase protection assay), and 3) changes in NMDA receptor subunit composition as measured by immunoprecipitation studies. Specific aim 4 will examine the relationship(s) of NMDA receptor subunit changes with changes in subunit phosphorylation. The overall hypothesis of this proposal is that prenatal ethanol exposure, even at modest concentrations, will result in demonstrable deficits in the function of NMDA receptors. We expect the magnitude of the deficits to be dose-related. It is hypothesized further that ethanol's actions in this regard may be linked with abnormalities of NMDA receptor phosphorylation.
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