Propofol suppresses a hyperpolarization-activated inward current in rat hippocampal CA1 neurons

We examined the effect of propofol and thiopental, intravenous anesthetics, on the hyperpolarization-activated inward current (H-1), whose functional role on the neuronal activity has been evaluated. Whole-cell recordings of 1(H) evoked by hyperpolarizing step pulses were taken from hippocampal CA1 neurons in rat brain slices. Propofol reduced 1(H) current in a dose-dependent manner. However, thiopental had no significant effect on the activation of 1(H). According to the functional role of 1(H), the suppression of 1(H) should result in a reduction of neuronal activity. We suggest that the effectiveness of propofol as an anticonvulsant or an antiemetic is associated with the blockade of the 1(H) channel. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.