(full paper is archived in the Miller Library)
Title: Effects of gadolinium on the ionic currents of squid
giant fiber lobe neurons
Student Author(s): Gundersen, Britter
Faculty Advisor(s): Thompson, Stuart and Gilly, William
Location: Final Papers Biology 176H
Date: June 2004
Abstract: The trivalent lanthanide ion gadolinium (Gd3+) has been shown to block various ion channels, particularly in mechanoreceptor systems, in which is has been used in a diagnostic manner. Gd3+ has also been shown to block voltage-gated channels in a number of systems, particularly L-, N-, and T-type Ca channels. The cells of the giant fiber lobe (GFL) of the stellate ganglion of squid are useful in a variety of electrophysiological studies, and their currents are well characterized, although the effects of Gd3+ on these currents have not been studied. We report a lack of effect of 20 mM Gd3+ on K, Na, and Ca currents in these cells, either in voltage-dependent properties or kinetics, although the Ca current (proposed to be due to a P-type Ca channel) warrants further investigation to unequivocally identify it as a Ca current and look for more subtle effects of Gd3+. This study adds to a long list of channels on which the effects of Gd3+ have been studied, and provides some preliminary information on the molecular structure of the pore of P-type Ca channels, as they appear to be insensitive to Gd3+ block at first approximation.