The results of these experiments will guide the formation of a testable model of the late steps in neurotransmitter exocytosis at a ribbon synapse. Then, modulation of this secretory pathway by physiologically relevant neurotransmitters, neuropeptides, and second messenger systems will be examined to determine the extent to which they modulate synaptic release. Calcium, in addition to its role in initiating release, may effect other parts of the secretory pathway. Therefore, the actions of calcium and calcium- activated conductances on synaptic release and synaptic vesicle cycling will also be examined. Armed with this information, predictions will be made about the effects of local circuit interactions and previous stimulus history on the throughput of visual information from photoreceptors to the third-order neurons of the retina.
Osteoporosis is a geriatric disease that has pediatric origins.
Development of peak bone mass, which is achieved by the third decade of life, is influenced by behaviors during childhood and adolescence, most notably calcium consumption and physical activity. National and local surveys indicate that adolescent girls have inadequate calcium intakes and lower than recommended levels of physical activity. Eighteen ethnically diverse middle schools from central Texas will be randomized into control or intervention conditions, with schools serving as the unit of randomization and analysis.