Intracellularly injected inositol hexakisphosphate induces a biphasic current in identified neurons of Aplysia.
Inositol hexakisphosphate (IP6) was pressure-injected into the somata of the identified neurons (R9-R12) in the abdominal ganglion of Aplysia. Intracellular injection of IP6 into a neuron voltage-clamped at -45 mV reproducibly induced a biphasic membrane current consisting of an inward current (Ii(IP6)) followed by a slow outward current (Io(IP6)). Conductance is increased at the peaks of these currents. The extrapolated reversal potential of Ii(IP6) was -34 mV, whereas Io(IP6) was increased by depolarization and decreased by hyperpolarization up to -75 mV, where it disappeared. Ion substitution and pharmacological experiments suggest that microinjection of IP6 into the Aplysia neurons activates two or more separate types of ion channels.
Sawada
M
M
Department of Physiology, Shimane Medical University, Izumo, Japan.
Ichinose
M
M
Maeno
T
T
D000818:Animals; D001048:Aplysia / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010833:Phytic Acid / Q000494:pharmacology*
D010833:Phytic Acid