Ciliary activity in Paramecium was investigated in different external solutions using techniques of voltage clamp and high frequency cinematography. An increase in the external concentration of K, Ca or Mg ions decreased the resting potential. It had no effect on ciliary activity. When the membrane potential was fixed, an increase in external Ca or Mg and, to a lesser extent, an increase in K concentration, raised the frequency of normal beating or decreased the frequency of reversed beating of the cilia. Similar effects resulted from membrane hyperpolarization with constant ionic conditions. Increase in concentration of Ca, but not of Mg or K, enhanced hyperpolarization-induced augmentation of ciliary frequency. Increase in Ca concentration also specifically augmented the delayed increase in inward current during rapid hyperpolarizing clamp. The results support the view that [Ca]i regulates the frequency and direction of ciliary beating. It is suggested that the insensitivity of the ciliary motor system to elevations of the external concentrations of ions results from compensation of their effects on [Ca]i. Depolarization itself appears to increase [Ca]i while elevation of the external ion concentrations at a fixed membrane potential appears to decrease [Ca]i.
Interactions of membrane potential and cations in regulation of ciliary activity in Paramecium
H. Machemer; Interactions of membrane potential and cations in regulation of ciliary activity in Paramecium. J Exp Biol 1 October 1976; 65 (2): 427–448. doi: https://doi.org/10.1242/jeb.65.2.427
Download citation file:
Advertisement
Cited by
Celebrating 100 years of discovery

We are proud to be celebrating 100 years of discovery in Journal of Experimental Biology. Visit our centenary webpage to find out more about how we are marking this historic milestone.
Craig Franklin launches our centenary celebrations

Editor-in-Chief Craig Franklin reflects on 100 years of JEB and looks forward to our centenary celebrations, including a supplementary special issue, a new early-career researcher interview series and the launch of our latest funding initiatives.
Looking back on the first issue of JEB

Journal of Experimental Biology launched in 1923 as The British Journal of Experimental Biology. As we celebrate our centenary, we look back at that first issue and the zoologists publishing their work in the new journal.
Webinar: Increasing the visibility and impact of your research
-HUBSwebinar.jpg?versionId=4510)
Would you like to increase the visibility and impact of your research and raise your profile internationally? If so, register for the very practical webinar we are running in association with HUBS on 23 February 2023.
Biology Communication Workshop: Engaging the world in the excitement of research
-BioCommunicationWorkshop.png?versionId=4510)
We are delighted to be sponsoring a Biology Communication Workshop for early-career researchers as part of JEB’s centenary celebrations. The workshop focuses on how to effectively communicate your science to other researchers and the public and takes place the day before the CSZ annual meeting, on 14 May 2023. Find out more and apply here.
Mexican fruit flies wave for distraction

Dinesh Rao and colleagues have discovered that Mexican fruit flies vanish in a blur in the eyes of predatory spiders when they wave their wings at the arachnids, buying the flies time to make their escape.