PMID- 14645448
OWN - NLM
STAT- MEDLINE
DCOM- 20041021
LR  - 20181113
IS  - 0022-3751 (Print)
IS  - 1469-7793 (Electronic)
IS  - 0022-3751 (Linking)
VI  - 555
IP  - Pt 3
DP  - 2004 Mar 16
TI  - Ca(2+) and frequency dependence of exocytosis in isolated somata of magnocellular 
      supraoptic neurones of the rat hypothalamus.
PG  - 699-711
AB  - In addition to action potential-evoked exocytotic release at neurohypophysial 
      nerve terminals, the neurohormones arginine vasopressin (aVP) and oxytocin (OT) 
      undergo Ca(2+)-dependent somatodendritic release within the supraoptic and 
      paraventricular hypothalamic nuclei. However, the cellular and molecular 
      mechanisms that underlie this release have not been elucidated. In the present 
      study, the whole-cell patch-clamp technique was utilized in combination with 
      high-time-resolved measurements of membrane capacitance (C(m)) and 
      microfluorometric measurements of cytosolic free Ca(2+) concentration 
      ([Ca(2+)](i)) to examine the Ca(2+) and stimulus dependence of exocytosis in the 
      somata of magnocellular neurosecretory cells (MNCs) isolated from rat supraoptic 
      nucleus (SON). Single depolarizing steps (> or =20 ms) that evoked 
      high-voltage-activated (HVA) Ca(2+) currents (I(Ca)) and elevations in 
      intracellular Ca(2+) concentration were accompanied by an increase in C(m) in a 
      majority (40/47) of SON neurones. The C(m) responses were composed of an initial 
      Ca(2+)-independent, transient component and a subsequent, sustained phase of 
      increased C(m) (termed DeltaC(m)) mediated by an influx of Ca(2+), and increased 
      with corresponding prolongation of depolarizing step durations (20-200 ms). From 
      this relationship we estimated the rate of vesicular release to be 1533 vesicles 
      s(-1). Delivery of neurone-derived action potential waveforms (APWs) as stimulus 
      templates elicited I(Ca) and also induced a DeltaC(m), provided APWs were applied 
      in trains of greater than 13 Hz. A train of APWs modelled after the bursting 
      pattern recorded from an OT-containing neurone during the milk ejection reflex 
      was effective in supporting an exocytotic DeltaC(m) in isolated MNCs, indicating 
      that the somata of SON neurones respond to physiological patterns of neuronal 
      activity with Ca(2+)-dependent exocytotic activity.
FAU - Soldo, Brandi L
AU  - Soldo BL
AD  - Department of Molecular and Integrative Physiology, University of Michigan 
      Medical School, Ann Arbor, MI 48109, USA.
FAU - Giovannucci, David R
AU  - Giovannucci DR
FAU - Stuenkel, Edward L
AU  - Stuenkel EL
FAU - Moises, Hylan C
AU  - Moises HC
LA  - eng
GR  - DA 03365/DA/NIDA NIH HHS/United States
GR  - DA 07268/DA/NIDA NIH HHS/United States
GR  - T32 DA007268/DA/NIDA NIH HHS/United States
GR  - R01 NS039914/NS/NINDS NIH HHS/United States
GR  - NS 39914/NS/NINDS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
DEP - 20031128
PL  - England
TA  - J Physiol
JT  - The Journal of physiology
JID - 0266262
RN  - 50-56-6 (Oxytocin)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Action Potentials
MH  - Animals
MH  - Calcium/*metabolism
MH  - Calcium Signaling
MH  - Cytosol/metabolism
MH  - Electric Capacitance
MH  - Electrophysiology
MH  - Exocytosis/*physiology
MH  - Fluorometry
MH  - Lactation/physiology
MH  - Neurons/metabolism/*physiology
MH  - Osmolar Concentration
MH  - Oxytocin/metabolism
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Reaction Time
MH  - Supraoptic Nucleus/metabolism/*physiology
PMC - PMC1664858
EDAT- 2003/12/03 05:00
MHDA- 2004/10/22 09:00
PMCR- 2005/03/16
CRDT- 2003/12/03 05:00
PHST- 2003/12/03 05:00 [pubmed]
PHST- 2004/10/22 09:00 [medline]
PHST- 2003/12/03 05:00 [entrez]
PHST- 2005/03/16 00:00 [pmc-release]
AID - jphysiol.2003.051136 [pii]
AID - 10.1113/jphysiol.2003.051136 [doi]
PST - ppublish
SO  - J Physiol. 2004 Mar 16;555(Pt 3):699-711. doi: 10.1113/jphysiol.2003.051136. Epub 
      2003 Nov 28.