Date of Award
Master of Science (MS)
Michael J. O'Donnell
Several previous studies of the blood brain barrier (BBB) of the American cockroach, Periplaneta americana, have shown that it is involved in the regulation of K+ and Na+ flux across the ventral nerve cord (VNC). Na+ flux is regulated in part by a Na+/K+-ATPase but few mechanisms involved in the regulation of K+ flux have been identified. Using the scanning ion-selective electrode technique (SIET) K+ flux across the VNC can be measured. This technique was used to determine whether K+ flux is actively regulated and whether the BBB is involved in the regulation of K+ flux. An uptake of K+ is seen at the connectives and an efflux is seen at the ganglion under some conditions indicating cycling of K+ from the ganglion to the connective may be occurring. A Na+/K+-ATPase appears to contribute to an influx of K+ at the ganglion but not the connective. It is postulated that a K+/H+-exchanger is involved in maintaining K+ levels at the ganglion. The presence of K+-channels (possibly Ca2+-gated) was detected at both the ganglion and the connective, although it appears that K+-channels play a greater role in regulating K+ flux at the connective. These results provide insights into the basic mechanisms regulating ion flux across the cockroach VNC.
Kocmarek, Andrea L., "Movement of K⁺ across the Blood-Brain Barrier of the American Cockroach, Periplaneta americana" (2009). Open Access Dissertations and Theses. Paper 4324.
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