Induction of outward current by orexin‐B in mouse peritoneal macrophages

Abstract

To define effects of novel feeding regulating peptides, orexins, in immunocompetent cells, ion channel activity in mouse peritoneal macrophages was analyzed by the perforated patch‐clamp method. Orexin‐B (OX‐B) induced an outward current at smaller holding potentials than K⁺ equilibrium potentials. Reversal potentials of OX‐B induced current were dependent on external K⁺ concentrations but not on external Cl⁻ concentration. Orexin‐A is less effective than OX‐B. Quinine blocked the outward current and tetraethylammonium partially suppressed the current. These results suggest that OX‐B can modulate macrophage functions through the activation of Ca²⁺‐dependent K⁺ channels.