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Neurotransmitter-driven activation of transcription factors is important for control of neuronal and neuroendocrine functions. We show with an in vivo approach that the norepinephrine cAMP-dependent rhythmic hormone production in rat pineal gland is accompanied by a temporally regulated switch in the ratio of a transcriptional activator, phosphorylated(More)
The hormone melatonin (5-methoxy-N-acetyltryptamine) is synthesized primarily in the pineal gland and retina, and in several peripheral tissues and organs. In the circulation, the concentration of melatonin follows a circadian rhythm, with high levels at night providing timing cues to target tissues endowed with melatonin receptors. Melatonin receptors(More)
Although the presence of arginine vasopressin (AVP) in the mammalian pineal has been characterized biochemically, the source of this nonapeptide hormone remains enigmatic. Most earlier data pointed to an extrapineal origin, although some recent evidence suggests intrapineal synthesis of AVP. The present study examined this issue using a combination of(More)
Mitochondrial dysfunction is a hallmark of Alzheimer's disease (AD) and is observed in mutant amyloid precursor protein (APP) transgenic mouse models of familial AD. Melatonin is a potent antioxidant, can prevent toxic aggregation of Alzheimer's beta-amyloid (Aβ) peptide and, when taken long term, can protect against cognitive deficits in APP transgenic(More)
Phosphorylation of cyclic AMP response element binding protein (CREB) at amino acid serine 133 appears as an important link between the norepinephrine (NE)-induced activation of second messenger systems and the stimulation of melatonin biosynthesis. Here we investigated in the rat pineal gland: 1) the type of protein kinase that mediates CREB(More)
Measurement of melatonin secretion throughout the night provides an index of net noradrenergic activity mediated by postsynaptic beta-adrenergic receptors in the pineal gland. Reduced melatonin secretion in some patients with depression might be related to reduced net noradrenergic function. However, a dysregulation in serotonin function has also been(More)
Most of what is known regarding adrenergic control of mammalian pineal functions has been derived from investigations with rodents. In an effort to provide a new animal model for pineal research, the bovine pineal gland was selected for practical and theoretical reasons. Bovine pinealocytes in monolayer culture were first characterized in terms of optimal(More)
Cyclic GMP formation in the rat pinealocyte has generally been thought to involve guanylate cyclases (GC) which are activated via GTP-regulatory proteins following beta 1-adrenergic receptor stimulation. Recent studies have also pointed to a cytosolic GC in these cells whose activity can be elevated by nitric oxide donors. Little attention has been paid to(More)
The distribution of neuropeptide Y-like immunoreactivity (NPY-LI) was investigated by immunohistochemistry and radioimmunoassay (RIA) in the brain of the Djungarian hamster (Phodopus sungorus) held under either long or short photoperiods. In the diencephalic and telencephalic structures studied, distinct patterns of NPY-LI were basically consistent in male(More)