Electrical parameters in gallbladders of different species their contribution to the origin of the transmural potential difference |
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Authors: | Hénin Silvio Cremaschi Dario Schettino Trifone Meyer Giuliano Donin Carla Lora Lamia Cotelli Franco |
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Institution: | (1) Istituto di Fisiologia Generalee di Chimica Biologica, Università di Milano, via Mangiagalli 32, Milano, Italy;(2) Istituto di fisiologia Generale, Universitá di Bari, via Amendola 165/A, Bari, Italy;(3) Istituto di Zoologia Laboratorio di Microscopia Elettronica, Université di Milano, Via Celonia 10, Milano, Italy |
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Abstract: | Summary Amphotericin B enhances Na+ conductance of the mucosal membrane of gallbladder epithelial cells and in such a way it modifies the brush border electromotive force. On this basis a method to measure cell and shunt resistances by comparing changes of the mucosal membrane potential (V
m
) and of the transmural p.d. (V
ms
) is developed. This method is applied in gallbladders of different vertebrate species (i.e. rabbit, guinea pig, goose, tortoise, toad, trout). The two tested mammals, rabbit and guinea pig, exhibited a lower shunting percentage (89–93%) than the nonmammals (96–97%), but this fact did not bring about a homogeneous positiveV
ms
. This means that shunting percent contributes, but it is not the only source of differences inV
ms
, in accordance with that reported by Gelarden and Rose (J. Membrane Biol.
19:37, 1974). Moreover, mammals exhibited a lower luminal resistance and a lower ratio between luminal and basolateral resistance than nonmammals. Possible causes of these differences are discussed. |
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Keywords: | |
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