A method for rapid exchange of solutions at membrane patches using a 10-microliters microcapsule
Koh, D.S.; Vogel, W.
Pflugers Archiv European Journal of Physiology 422(6): 609-613
1993
ISSN/ISBN: 0031-6768 PMID: 8469612 Document Number: 410111
A rapid exchange (less than 2 ms) of the bath solution facing a membrane patch is accomplished by driving the tip of a pipette from the bath through a 100-mu-m oil layer into a small capsule filled with 10 mu-l test solution. The microcapsule method can be applied to both excised patch configurations, inside-out and out-side-out patches. On and off reactions of Ca-2+-activated K+ channel activity have been recorded after changing the intracellular Ca-2+ concentration using an inside-out patch. A blockade of these K+ channels by external tetraethylammonium ions is demonstrated with an out-side-out patch. The blocking kinetics of delayed-rectifier K+ channels by a purified peptide toxin from snake venom, dendrotoxin, could be measured with our microcapsule method. Using tiny volume of test solutions this method can be helpful in experiments involving scarce or expensive solutions.