Talking about bioelectrical potentials using rings of the mesenteric artery without glass micropipettes
| Autor: | Teresinha S. Brito, R. J. B. de Siqueira, Moisés Tolentino Bento da Silva, Vasco Pinheiro Diógenes Bastos, Francisco J.B. Lima, Helder Veras Ribeiro-Filho, Pedro Jorge Caldas Magalhães, Armênio Aguiar dos Santos, João Paulo Melo de Pinho, F. Cosker, Daniel Freire de Sousa |
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| Rok vydání: | 2012 |
| Předmět: |
Male
Physiology Education Membrane Potentials symbols.namesake Organ Culture Techniques Isometric Contraction medicine Animals Humans Nernst equation Equilibrium potential Rats Wistar Students Chemistry Pipette General Medicine Anatomy Resting potential Mesenteric Arteries Rats medicine.anatomical_structure symbols Glass Biomedical engineering Artery |
| Zdroj: | Advances in physiology education. 36(4) |
| ISSN: | 1522-1229 |
| Popis: | In the present study, a practical activity is proposed to adopt an experimental approach to demonstrate the relationship between the equilibrium potential for K+ and transmembrane electrical potential without glass micropipettes. A conventional setup for recording contractile activity of isolated smooth muscle preparations was used based on the events elegantly described by Somlyo and Somlyo in the 1960s. They showed that, in response to a given stimulus, smooth muscle cells may contract, recruiting electromechanical or pharmacomechanical coupling by mechanisms that involve, or not, changes in transmembrane potential, respectively. By means of contractions and relaxations of a ring-like preparation from the rat mesenteric artery, it is possible to observe the functional consequences of handling K+ concentration in the extracellular compartment and the effects caused by opening K+ channels in that preparation, which are significant when the cell membrane establishes an electrical potential difference between intra- and extracellular compartments (driven mainly by K+ permeability under resting conditions). The effects observed by students fit well with values predicted by Nernst and Goldman-Hodgin-Katz equations, and we demonstrated that the activity is able to improve students' comprehension regarding basic principles of bioelectricity. |
| Databáze: | OpenAIRE |
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