Possible role during exocytosis of a ca2+-activated channel in neurohypophysial granules

doi:10.1016/0896-6273(92)90299-S

Neuron

Volume 8, Issue 2, February 1992, Pages 335-342

https://doi.org/10.1016/0896-6273(92)90299-S Get rights and content

Abstract

Ion channels from bovine neurohypophysial granules were incorporated into artificial lipid bilayers. The larger amplitude channel is permeable to cations and exhibits multiple conductances. The channel opens only in the presence of free Ca²⁺, but is inhibited by relatively high Ca²⁺ concentrations. Release of vasopressin from permeabilized neurohypophysial terminals also shows a similar biphasic dependence on Ca²⁺. Release is selectively inhibited by low concentrations of the long-chain alcohol octanol, but not by high concentrations of ethanol, as is the neurosecretory granule Ca²⁺-activated cation channel. Furthermore, Ca ²⁺-evoked release and channel activity are both inhibited by the long-chain tetraethylammonium analogs decamethonium and decyl-triethyl ammonium bromide. The close correlation between channel and release properties lead us to conclude that the Ca²⁺-activated channel is involved in peptide secretion.

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For example, secretory granules contain ion channels. One of these is a large-conductance, calcium-dependent cation channel whose function is unknown, but may be important for releasing calcium for calcium-dependent fusion, or may contribute to the pore through which neurotransmitter gets released into the extracellular space [140–142]. As pointed out earlier, InsP3 receptors have also been reported on secretory granules [56].
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^†: Present address: Department of Cardiothoracic Surgery, Inha General Hospital, Inha University College of Medicine, 3309-327 Taepyungdong, Seongnam City, Korea.

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Neuron

ArticlePossible role during exocytosis of a ca2+-activated channel in neurohypophysial granules

Abstract

Neuron

Biophys. J.

Neuron

Cell

Prog. Biophys. Mol. Biol.

Neuroscience

Biophys. J.

Cell

Alien intracellular calcium chelators attenuate neurotransmitter release at squid giant synapse

J. Neurosci.

Exocytosis

Annu. Rev. Physiol.

Intracellular neutral carrier-based Cal' microelectrode with subnanomolardetection limit

PfliigersArch.

Ionic pores, gates and gating currents

Quart. Rev. Biophys.

Calcium action in synaptic transmitter release

Annu. Rev. Neurosci.

Role of Ca-activated K channels in transmitter release at the squid giant synapse

J. Physiol.

Currents through the fusion pore that forms during exocytosis of a secretory vesicle

Nature

Final steps in exocytosis observed in a cell with giant secretory granules

Depolarization induced Ca2+ increase in isolated neurosecretory nerve terminals measured with fu ra-2

The role of patterned burst and interburst interval on the excitationcoupling mechanism in the isolated rat neural lobe

J. Physiol.

Requirements for hormone release from permeabilized nerve endings isolated from the rat neurohypophysis

J. Physiol.

Osmotic swelling of phospholipid vesicles causes them to fuse with planar phospholipid bilayer membrane

Science

Parameters affecting the fusion of unilamellar phospholipid vesicles with planar bilayer membranes

J. Cell Biol.

Recent advances in planar phospholipid bilayer techniques for monitoring ion channels

Annu. Rev. Biophys. Biophys. Chem.

Pathways to regulated exocytosis in neurons

Annu. Rev. Physiol.

Stimulus-secretion coupling in a neurosecretory organ: the role of calcium in the release of vasopressin from neurohypophysis

J. Physiol.

Osmotic swelling of vesicles

Annu. Rev. Physiol.

Capacitance measurements reveal stepwise fusion events in degranulating mast cells

Nature

Calculation and control of free divalent cations in solutions used for membrane fusion studies

Meth. Enzymol.

Article
Possible role during exocytosis of a ca²⁺-activated channel in neurohypophysial granules

Depolarization induced Ca²⁺ increase in isolated neurosecretory nerve terminals measured with fu ra-2