EXCEED THE SPACE PROVIDED. The ability of prenatal alcohol to cause hyperactivity of the mature offspring hypothalamic-pituitary-adrenal (HPA) axis is well established, but the mechanisms mediating this phenomenon remain poorly understood. Levels of nitric oxide (NO) and catecholamines, both of which stimulate the HPA axis, are reportedly altered by prenatal alcohol.
Under Specific Aim 1, we will therefore investigate the role of these secretagogues in mediating the influence of the drug. Specifically, we will determine if prenatal alcohol alters basal levels of NO and/or norepinephrine and dopamine; whether the stimulatory effect that NO and catecholamines exert on the HPA axis of the mature offspring is modified; and whether prenatal alcohol alters the ontogeny of hypothalamic corticotropin releasing factor (CRF).
Under Specific Aim 2, we will extend these studies to the role of specific receptors for CRF, the hypothalamic peptide that is the primary regulator of the HPA axis. Specifically, we will test the hypothesis that CRF receptors type 1, but not type 2 are indispensable in allowing the influence of prenatal alcohol to be exerted on the offspring' HPA axis. These experiments will be carried out in mutant mice lacking the gene for these receptors. Finally, Specific Aim 3 will be devoted to continue our studies of the mechanisms through which postnatal alcohol alters HPA axis activity in rats. We have shown that exposure to this drug blunted this axis' response to a variety of stressors. Very recently we also showed that alcohol modified the ability of these stressors to upregulate NO levels. In the present grant we will identify the type of NO synthase isoform(s) that mediate(s) the influence of alcohol on nitrergic pathways, and test the hypothesis that alcohol-induced changes in the functional interactions between CRF and NO represent important mechanisms modulating the influence of this drug. PERFORMANCE SITE ========================================Section End===========================================
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