TheXenopusoocyte is a widely used model cell for studies of signal transduction mechanisms. Advances in microanalytical methods have made it feasible to perform rapid, localized collection of cytoplasm from individualXenopusoocytes. Analytes contained in the cytoplasmic sample are separated by electrophoresis in a capillary and simultaneously transferred to a detection region. The development of bioengineered cells as sensitive detectors of intracellular components made quantitative measurements of native signaling molecules within the electrophoresed sample possible. Local determination of the second messenger inositol 1,4,5-trisphosphate is described to illustrate the methods for the sampling, electrophoresis, detection, and quantification of signaling molecules in single oocytes.
