| Popis: |
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. Master of Science (MS) |
