Masters Theses

Date of Award

12-1986

Degree Type

Thesis

Degree Name

Master of Science

Major Professor

John R. Kennedy

Abstract

Studies show that ciliary beat frequency is regulated by the intracellular calcium concentration. To further study the calcium-induced frequency increase of individual cells, ciliated cells were exposed to various concentrations of extracellular calcium in the presence of calcium ionophore A23187, and the ciliary frequencies were then monitored continuously for up to 15 minutes. This method allowed for characterization of the calcium-induced ciliary increase in each cell over time.

Ciliated cells of rabbit tracheas were incubated for 30 minutes in calcium concentrations of 0.88 mM, 1.6 mM, 2.6 mM or 5.0mM. When calcium ionophore A23187 at 1 x 10-6 M was added, ciliary frequencies of individual cells began to increase, usually reaching a maximum frequency 10 minutes after addition of ionophore. After reaching their maximum frequencies, the frequencies began to decline. At 2.6 mM calcium, the calcium-induced frequency increase appeared to be related to the baseline frequency of individual cells. There was also evidence that the maximum frequency attained was directly related to the extracellular calcium concentration up to 2.6 mM calcium. The average calcium-induced frequency increase was greatest at 2.6 mM calcium, producing an average increase of 7.3 Hz. The average frequency increases at 0.88 mM and 1.6 mM were 5.6 Hz and 5.7 Hz respectively, and the average increase at 5.0 mM calcium was 4.6 Hz.

The results of this series of experiments can be used to further characterize normal ciliary activity. In 88% of the cells tested at 2.6 mM calcium, the maximum calcium-induced frequency was as high or higher than the frequency shift seen in the control recording of these cells. Only 7% of the cells with 0.88 mM calcium in the media reached maximum frequencies as high as the peak frequencies seen in their control recordings. A possible mechanism for this increase is suggested.

The results can also be used to describe metachronal waveforms and ciliary coordination between adjacent cells. Adjacent cells producing a metachronal wave appeared to maintain their coordination throughout the calcium-induced increase in ciliary frequency at all four of the calcium concentrations as observed by the swift, directed movement of particles in the media. The data shows that cells producing the wave were beating at different frequencies. Apparently mechanical coordination of adjacent cilia is not the only force determining ciliary frequency between adjacent cells. In the presence of A23187, several coordinated cells reached the same maximum calcium-induced frequency regardless of their baseline frequencies. This resulted in maintenance of the metachronal wave during the calcium-induced increase.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS