AGI April 41/4

Hanani, M., M. Francke, W. Härtig, J. Grosche, A. Reichenbach, and T. Pannicke. Patch-clamp study of neurons and glial cells in isolated myenteric ganglia. Am J Physiol Gastrointest Liver Physiol 278: G644–G651, 2000.— Most of the physiological information on the enteric nervous system has been obtained from studies on preparations of the myenteric ganglia attached to the longitudinal muscle layer. This preparation has a number of disadvantages, e.g., the inability to make patch-clamp recordings and the occurrence of muscle movements. To overcome these limitations we used isolated myenteric ganglia from the guinea pig small intestine. In this preparation movement was eliminated because muscle was completely absent, gigaseals were obtained, and whole cell recordings were made from neurons and glial cells. The morphological identity of cells was verified by injecting a fluorescent dye by micropipette. Neurons displayed voltagegated inactivating inward Na1 and Ca21 currents as well as delayed-rectifier K1 currents. Immunohistochemical staining confirmed that most neurons have Na1 channels. Neurons responded to GABA, indicating that membrane receptors were retained. Glial cells displayed hyperpolarizationinduced K1 inward currents and depolarization-induced K1 outward currents. Glia showed large ‘‘passive’’ currents that were suppressed by octanol, consistent with coupling by gap junctions among these cells. These results demonstrate the advantages of isolated ganglia for studying myenteric neurons and glial cells.