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This Article Full Text Full Text (PDF) All Versions of this Article: 294/3/G648    most recent 00040.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sevcencu, C. Articles by Gregersen, H. Search for Related Content PubMed PubMed Citation Articles by Sevcencu, C. Articles by Gregersen, H.

NEUROREGULATION AND MOTILITY

Simultaneous monitoring of cellular depolarization and contraction: a new method to investigate excitability and contractility in isolated smooth muscle cells

¹Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Denmark; ²Department of Experimental Biology, Faculty of Biology and Geology, "Babes-Bolyai" University, Cluj-Napoca, Romania; ³Center of Excellence in Visceral Biomechanics and Pain, Aalborg Hospital, Aalborg, Denmark; ⁴Biomedical Engineering Department, Indiana University-Purdue University, Indianapolis, Indiana

Submitted 22 January 2007 ; accepted in final form 10 January 2008

The present experiments were performed to establish a method for simultaneous monitoring of excitation and contraction in isolated smooth muscle cells. The smooth muscle cells were dissociated from the colons of Wistar rats by enzymatic digestion. All the experiments were performed on mixtures of circular and longitudinal cells. In a first set of experiments, focal extracellular potentials (FEPs) and transmembrane action potentials (APs) were simultaneously recorded from the cells by use of extracellular and intracellular pipettes, respectively. In a second set of experiments, cellular contraction induced by chemical stimulation was monitored simultaneous with the FEP recordings. The FEPs had spike and plateau amplitudes of 44.5 ± 2.3 and 8.9 ± 0.7 mV, respectively, and reproduced the general morphology of gastrointestinal APs. The parallel mechanical measurements from the rat colonic cells showed that they shortened with an average peak contraction of 8.8 ± 1.4 µm and an average contraction velocity of 8.2 ± 0.9 µm/s, to develop an average peak force of 1.2 ± 0.2 µN, and generated an average peak power of 36 ± 15 pW. Simultaneous monitoring of FEPs and cellular contraction demonstrates correlations between the electrical and mechanical events taking place in the investigated cells.

isolated cells; focal extracellular potential; cellular contraction