Steve A Kay3
Michael L Johnson2
Craig S Nunemaker2
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In Drosophila, a number of key processes such as emergence from the pupal case, locomotor activity, feeding, olfaction, and aspects of mating behavior are under circadian regulation. Although we have a basic understanding of how the molecular oscillations take place, a clear link between gene regulation and downstream biological processes is still missing.(More)
Neurons in the mammalian suprachiasmatic nuclei (SCN) generate daily rhythms in physiology and behavior, but it is unclear how they maintain and synchronize these rhythms in vivo. We hypothesized that parallel signaling pathways in the SCN are required to synchronize rhythms in these neurons for coherent output. We recorded firing and clock-gene expression(More)
The rapid turnover of luciferase and the sensitive, non-invasive nature of its assay make this reporter gene uniquely situated for temporal gene expression studies. To determine the in vivo regulatory pattern of the Drosophila clock gene period (per), we generated transgenic strains carrying a luciferase cDNA fused to the promoter region of the per gene.(More)
The central circadian pacemaker is located in the hypothalamus of mammals, but essentially the same oscillating system operates in peripheral tissues and even in immortalized cell lines. Using luciferase reporters that allow automated monitoring of circadian gene expression in mammalian fibroblasts, we report the collection and analysis of precise rhythmic(More)
BACKGROUND The AP-1 family of transcription factors has been implicated in the control of the expression of many genes in response to environmental signals. Previous studies have provided temporal profiles for c-fos expression by taking measurements from many animals at several points in time, but these studies provide limited information about dynamic(More)
Pulsatile release of GnRH is prerequisite for fertility. The possibility that multiple rhythms interact to generate GnRH pulses was raised by observations of changes in action potential firing and intracellular calcium levels occurring much more frequently than hormone pulses. To examine this further, we analyzed firing patterns from targeted extracellular(More)
Growth hormone (GH) secretion, controlled principally by a GH-releasing hormone (GHRH) and GH release-inhibiting hormone [somatostatin (SRIF)] displays vivid sexual dimorphism in many species. We hypothesized that relatively small differences within a dynamic core GH network driven by regulatory interactions among GH, GHRH, and SRIF explain the gender(More)
Chick pineal cells in culture display a circadian rhythm of melatonin release. Light pulses can entrain (phase shift) the rhythm. One candidate for the photoentrainment pathway uses a mitogen-activated protein kinase (MAPK), also known as extracellular signal-regulated kinase (ERK). We tested the hypothesis that activation of ERK (by phosphorylation to(More)
PURPOSE Hypothalamic regulation of the reproductive axis in temporal lobe epilepsy (TLE), represented by the ultradian pulsatile secretion of luteinizing hormone (LH), has been shown to be altered interictally and postictally. Our objective is to determine if epilepsy or seizures disrupt normal circadian fluctuations of LH as well as circadian organization(More)
GnRH neurons form the final common pathway for regulating fertility. Estradiol feedback controls GnRH release, but the cellular mechanisms are unknown. Targeted extracellular recordings were used to examine the firing rate of GFP-identified GnRH neurons in a model for estradiol negative feedback (OVX vs. OVX+E). Episodes of increased firing rate occurred in(More)