Meeting Abstract

58.2  Tuesday, Jan. 6  Dye- and electrical-coupling between gastric and pyloric neurons in the stomatogastric ganglion of the lobster Homarus americanus, BIERMAN, H.S.*; TOBIN, A-E; REHM, K.J.; MARDER, E.; Brandeis University, Waltham, MA; Brandeis University, Waltham, MA; Brandeis University, Waltham, MA; Brandeis University, Waltham, MA hilaryb@brandeis.edu

The importance and prevalence of electrical synapses in vertebrate and invertebrate systems has been increasingly noted. To examine how electrical synapses contribute to network function we focus on the well-defined stomatogastric system that controls rhythmic chewing and filtering in the stomach of the lobster Homarus americanus. This system is ideal for studying electrical synapses because the 30 large neurons which compose the network are individually identifiable between animals, and much of their chemical connectivity is known. This system generates two separate but coordinated rhythms (gastric and pyloric). Neurons such as the dorsal gastric (DG) neuron, which show both rhythms, may be coupled to neurons in both rhythmic networks. Previously, no electrical connections to DG have been identified. To determine DG’s electrically coupled partners, we used both dye-coupling and electrophysiological techniques. Recordings were made to identify each cell in the ganglion, and neurobiotin was injected into DG. Following processing with fluorescently tagged streptavidin, the dye-coupled partners were determined by confocal microscopy. Electrical coupling was measured by injecting current into DG and recording voltage responses in other cells. Both techniques identified a number of neurons coupled to DG including the pyloric dilator neuron (PD) and the lateral posterior gastric neuron (LPG). Supported by NIH grants NS059255(AET) and T32 NS007293(Brandeis).