[
International Worm Meeting,
2015]
A pair of ASE chemosensory neurons, ASEL and ASER, are major salt sensors, and play critical roles in chemotaxis to NaCl. Calcium imaging has previously revealed that ASEL and ASER are activated by an increase and decrease in NaCl concentrations, respectively (Suzuki et al., 2008; Ortiz et al., 2009). These asymmetric responses by ASEL and ASER to changes of NaCl concentrations are crucial to efficient chemotaxis of C. elegans toward higher concentrations of NaCl. While Goodman et al. (1998) reported in situ whole-cell patch-clump recording of ASER, electrophysiological characterisation of ASE neurons is still required to understand how the neurons respond to the NaCl concentration changes.Toward the goal, we have investigated electrophysiological properties of ASE neurons in wild-type C. elegans by in vivo whole-cell patch-clamp recordings, and have found that both of ASE neurons showed resting membrane potentials of approximately -60 mV and membrane resistances of about 2 Gomega. In both of ASE neurons, voltage responses to current injections showed solitary action potentials. Depolarization of wild-type ASEL was observed when a puff of 150 mM NaCl was applied to the animal's nose in bath solution containing 50 mM NaCl. On the other hand, a puff of NaCl-free buffer induced ASER depolarization. These results are consistent with those of calcium imaging. To understand roles of the action potentials in ASE, we are currently trying to analyse electrophysiological properties of ASE neurons in various mutants.References1. Suzuki et al., Nature 454: 114-118 (2008)2. Ortiz et al., Current Biology 19: 996-1004 (2009)3. Goodman et al., Neuron 20: 763-772 (1998).