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Properties of unitary potentials generated by intramuscular interstitial cells of Cajal in the murine and guinea‐pig gastric fundus
Author(s) -
Beckett E. A. H.,
Bayguinov Y. R.,
Sanders K. M.,
Ward S. M.,
Hirst G. D. S.
Publication year - 2004
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2004.063016
Subject(s) - antrum , interstitial cell of cajal , membrane potential , biophysics , depolarization , fundus (uterus) , hyperpolarization (physics) , chemistry , stomach , anatomy , biology , endocrinology , biochemistry , medicine , stereochemistry , ophthalmology , smooth muscle , nuclear magnetic resonance spectroscopy
Intracellular recordings were made from isolated bundles of the circular muscle layer of mouse and guinea‐pig gastric fundus. These preparations displayed an ongoing discharge of membrane noise (unitary potentials), similar to that recorded from similar preparations made from the circular layer of the antrum. Bundles of muscle from the fundus of W/W V mice, which lack intramuscular interstitial cells of Cajal (ICC IM ) lacked the discharge of membrane noise observed in wild‐type tissues. When the membrane potential was changed by passing depolarizing or hyperpolarizing current pulses, the discharge of membrane noise was little changed. The membrane noise was unaffected by adding chloride channel blockers; however, agents which buffered the internal concentration of calcium ions reduced the discharge of membrane noise. Treatment of tissues with CCCP, which interferes with the uptake of calcium ions by mitochondria, also reduced the membrane noise and caused membrane hyperpolarization. Similar observations were made on bundles of tissue isolated from the circular layer of the guinea pig antrum. Together the observations indicate that membrane noise is generated by a pathway located in ICC IM . The properties of this pathway appear to vary dramatically within a given organ. The lack of voltage sensitivity of the discharge of membrane noise in the fundus provides a possible explanation for the lack of rhythmic electrical activity in this region of the stomach.