Jul 29, 2006

Electrical properties and cell-to-cell communication of the salivary gland cells of the snail, Helix pomatia

Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Zsolt PirgerTibor Kiss

Abstract

The aim of the present study was to assess the cellular mechanism of secretion in the salivary gland of the snail, Helix pomatia, using electrophysiological, electron microscopic and immunohistochemical techniques. A homogeneously distributed membrane potential (-56.6 +/- 9.8 mV) was determined mainly by a K+ -electrochemical gradient and partly by the contribution of the electrogenic Na+ -pump and Cl- conductance. Low resistance electrical coupling sites were identified physiologically. Transmission electron microscopy and innexin 2 antibody revealed the presence of gap-junction-like membrane structures between gland cells. It is suggested that gap-junctions are sites of electrotonic intercellular communication, which integrate the gland cells into a synchronized functional unit in the acinus. Stimulation of the salivary nerve elicited secretory potentials (depolarization) which could be mimicked by local application of acetylcholine, dopamine or serotonin. In voltage-clamp experiments four major conductances were identified: a delayed rectifier (IK), a transient (IA) and a Ca2+ -activated outward K+ current (IK(Ca)) and Ca2+ -inward currents (ICa). It is suggested that one or more of these conductances may give rise to a stim...Continue Reading

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Mentioned in this Paper

Vertebrates
Biochemical Pathway
Gastropoda
Calcium [EPC]
Tissue Membrane
Molecular Helix
Physiologic Pulse
Glycerin
SLC25A29 gene
Planorbella

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