Signal transduction and regulation of melatonin synthesis in bovine pinealocytes: impact of adrenergic,peptidergic and cholinergic stimuli |
| |
Authors: | Christof Schomerus Elke Laedtke James Olcese Joan L. Weller David C. Klein Horst-Werner Korf |
| |
Affiliation: | 1.Dr. Senckenbergische Anatomie, Institut für Anatomie II, Johann Wolfgang Goethe-Universit?t Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt/Main, Germany,;2.Institut für Hormon- und Fortpflanzungsforschung, Universit?t Hamburg, Grandweg 64, 22529 Hamburg, Germany,;3.Section on Neuroendocrinology, Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-4480, USA, |
| |
Abstract: | Limited studies of the regulation of pineal melatonin biosynthesis in ungulates indicate that it differs considerably from that in rodents. Here we have investigated several signal transduction cascades and their impact on melatonin synthesis in bovine pinealocytes. Norepinephrine increased the intracellular calcium ion concentration ([Ca2+]i) via alpha(1)-adrenergic receptors. Activation of beta-adrenergic receptors enhanced cAMP accumulation and rapidly elevated arylalkylamine N-acetyltransferase (AANAT) activity and melatonin secretion. The beta-adrenergically evoked increases in AANAT activity were potentiated by alpha(1)-adrenergic stimulation, but this was not seen with cAMP or melatonin production. PACAP treatment caused small increases in cAMP, AANAT activity and melatonin biosynthesis, apparently in a subpopulation of cells. VIP and glutamate did not influence any of these parameters. Activation of nicotinic and muscarinic acetylcholine receptors increased [Ca2+]i, but did not alter cAMP levels, AANAT activity or melatonin production. Our study reveals that discrete differences in pineal signal transduction exist between the cow and rodent, and emphasizes the potential importance that the analysis of ungulate pinealocytes may play in understanding regulation of pineal melatonin biosynthesis in primates and man, whose melatonin-generating system appears to be more similar to that in ungulates than to that in rodents. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|