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Synchronized Periodic Ca2+ Pulses Define Neurosecretory Activities in Magnocellular Vasotocin and Isotocin Neurons

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Title: Synchronized Periodic Ca2+ Pulses Define Neurosecretory Activities in Magnocellular Vasotocin and Isotocin Neurons
Authors: Saito, Daisuke Browse this author
Urano, Akihisa Browse this author
Keywords: neurosecretion
vasotocin
magnocellular neuron
rainbow trout
osmoregulation
synchronization
calcium oscillation
phasic burst
Issue Date: 1-Nov-2001
Publisher: Society for Neuroscience
Journal Title: Journal of Neuroscience
Volume: 21
Issue: 21
Start Page: RC178
Abstract: The electrical activity of magnocellular neurosecretory cells (NSCs) is correlated with the release rates of neurohypophysial hormones. NSCs may control their secretory activity in a cooperative manner by changing their electrical activity in response to changes in the internal milieu. In the present study, we applied confocal Ca2+ imaging to a sagittally hemisected rainbow trout brain to simultaneously monitor the neuronal activity of a number of NSCs. We found that NSCs in vitro showed synchronized pulsatile elevations of intracellular Ca2+ levels at regular intervals. Double immunostaining of vasotocin (VT) and isotocin (IT) after the confocal imaging clarified that each of the VT and IT neuronal populations showed a distinct pattern of periodic Ca2+ pulses. Simultaneous cell-attached patch recordings ensured that individual Ca2+ pulses were associated with a phasic burst firing. Depolarizing stimuli by increasing the extracellular K+ concentration from 5 to 7-9 mM reversibly shortened the interpulse intervals in both VT and IT neurons. Interpulse intervals but not durations of pulses were shortened by hypo-osmotic stimuli and prolonged by hyperosmotic stimuli, consistent with the osmoregulatory function of teleost NSCs. We therefore hypothesize that NSCs use intervals of synchronized periodic burst discharges to fit the levels of secretory activity to physiological requirements.
Rights: Copyright © 2001 Society for Neuroscience
Type: article
URI: http://hdl.handle.net/2115/43972
Appears in Collections:理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 浦野 明央

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