Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: Characterization of voltage-gated potassium currents in pedal-ganglion neurons of the gastropod mollusc Strombus luhuanus
Student Author(s): DeConde, Rob
Faculty Advisor(s): Gilly, William
Pages: 40
Location: Final Papers Biology 176H
Date: 2001 2001
Abstract: The gastropod mollusc Strombus luhuanus, prey to some Conus snails, exhibits a morphologically unique extendable foot utilized for fast escape response. The pedal ganglion of specimens was identified using in situ stimulation of radiating axon bundles and observing pedal response. Once the two lobes were removed, neurons were dissociated using glass teasing needles and studied under whole-cell patch clamp. Outward potassium currents were observed to have complex activation kinetics and biphasic inactivation. These kinetics were characterized and used to develop a pre-pulse protocol for current separation. Two distinct voltage-gated potassium currents were identified and isolated using this pre-pulse procedure. The fast activating and inactivation current resembled a classic A-current and could reach peak current within 2 milliseconds after pulse initiation for large depolarizations, and inactivated completely in about 30 ms. The second component of potassium current resembled a delayed rectifier and exhibited slow and incomplete inactivation, with peak current occurring within 5 or 6 milliseconds for large depolarizations and partial inactivation over the much longer period of about 150 milliseconds. The kinetic properties of each individual current were analyzed and described and a model based on Hodgkin-Huxley was used to compute conductance time course as a function of voltage.