The chambered nautilus (Nautilus spp.) is the sole surviving genus of the once dominant externally-chambered cephalopods. Nautilus achieves its near-neutral buoyance in seawater via the gas-filled chambers of its heavy protective shell. The siphuncle, the organ that passes through the animal's chambers, removes the cameral liquid which initially fills the chambers, and allows gas (mostly N2) to enter. Thus, the siphuncle is the organ responsible for nautilus' buoyancy. To understand how the siphuncle empties and partially fills chambers, studies of this transport and electrophysiology and required. Prior to writing a formal proposal involving microelectrode and flux experiments, preliminary studies are required to show that the appropriate measurements can be made on siphuncular cells in vitro. This SGER proposal will attempt to demonstrate the feasibility of those methods. This SGER proposal is exploratory and high risk because in vitro studies of the siphuncle have never been done and there is no quarantee that the siphuncle is a useful system for microelectrode and tracer experiments.***
