Document Detail

Regulation of activity-dependent dendritic vasopressin release from rat supraoptic neurones.
MedLine Citation:
PMID:  15731188     Owner:  NLM     Status:  MEDLINE    
Magnocellular neurones of the hypothalamus release vasopressin and oxytocin from their dendrites and soma. Using a combination of electrophysiology, microdialysis, in vitro explants, and radioimmunoassay we assessed the involvement of intracellular Ca(2+) stores in the regulation of dendritic vasopressin release. Thapsigargin and cyclopiazonic acid, which mobilize Ca(2+) from intracellular stores of the endoplasmic reticulum, evoked vasopressin release from dendrites and somata of magnocellular neurones in the supraoptic nucleus. Thapsigargin also produced a dramatic potentiation of dendritic vasopressin release evoked by osmotic or high potassium stimulation. This effect is long lasting, time dependent, and specific to thapsigargin as caffeine and ryanodine had no effect. Furthermore, antidromic activation of electrical activity in the cell bodies released vasopressin from dendrites only after thapsigargin pretreatment. Thus, exposure to Ca(2+) mobilizers such as thapsigargin or cyclopiazonic acid primes the releasable pool of vasopressin in the dendrites, so that release can subsequently be evoked by electrical and depolarization-dependent activation. Vasopressin itself is effective in inducing dendritic vasopressin release, but it is ineffective in producing priming.
Mike Ludwig; Philip M Bull; Vicky A Tobin; Nancy Sabatier; Rainer Landgraf; Govindan Dayanithi; Gareth Leng
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-02-24
Journal Detail:
Title:  The Journal of physiology     Volume:  564     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2005 Apr 
Date Detail:
Created Date:  2005-04-13     Completed Date:  2005-08-23     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  515-22     Citation Subset:  IM    
Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK.
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MeSH Terms
Calcium Channel Blockers / pharmacology
Dendrites / drug effects,  metabolism,  secretion*
Neurons / drug effects,  metabolism,  secretion*
Rats, Sprague-Dawley
Rats, Wistar
Supraoptic Nucleus / drug effects,  metabolism,  secretion*
Thapsigargin / pharmacology
Vasopressins / metabolism,  secretion*
Reg. No./Substance:
0/Calcium Channel Blockers; 11000-17-2/Vasopressins; 67526-95-8/Thapsigargin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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