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This Article Full Text Full Text (PDF) All Versions of this Article: 586/3/795    most recent jphysiol.2007.145284v1 Services Email this article to a friend Similar articles in this journal 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 Wladyka, C. L. Articles by Kunze, D. L. Search for Related Content PubMed PubMed Citation Articles by Wladyka, C. L. Articles by Kunze, D. L. Related Collections Neuroscience

¹ Rammelkamp Center for Education and Research, MetroHealth Medical Center and Departments of Neurosciences, Case Western Reserve University, Cleveland, OH 44109, USA
² Department of Biomedical Engineering, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA

The ion channels responsible for the pattern and frequency of discharge in arterial baroreceptor terminals are, with few exceptions, unknown. In this study we examined the contribution of KCNQ potassium channels that underlie the M-current to the function of the arterial baroreceptors. Labelled aortic baroreceptor neurons, immunohistochemistry and an isolated aortic arch preparation were used to demonstrate the presence and function of KCNQ2, KCNQ3 and KCNQ5 channels in aortic baroreceptors. An activator (retigabine) and an inhibitor (XE991) of the M-current were used to establish a role for these channels in setting the resting membrane potential and in regulating the response to ramp increases in arterial pressure. Retigabine raised the threshold for activation of arterial baroreceptors and shifted the pressure–response curve to higher aortic pressures. XE991, on the other hand, produced an increase in excitability as shown by an increase in discharge at elevated pressures as compared to control. We propose that KCNQ2, KCNQ3 and KCNQ5 channels provide a hyperpolarizing influence to offset the previously described depolarizing influence of the HCN channels in baroreceptor neurons and their terminals.

(Received 21 September 2007; accepted after revision 28 November 2007; first published online 29 November 2007)
Corresponding author D. L. Kunze: Rammelkamp Center for Research and Education R326, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109-1998, USA. Email: dkunze{at}metrohealth.org