Extracellular tumor necrosis factor induces a decreased K+ conductance in an identified neuron of Aplysia kurodai.
Recombinant human tumor necrosis factor (rhTNF) was pressure-applied onto the the soma of identified neuron R12 in the Aplysia abdominal ganglion. rhTNF induced a slow inward current (ITNF, 80-100 s in duration, 5-10 nA in amplitude) associated with a conductance decrease. ITNF begins 1-2 s after applying rhTNF and peaks in 5-6 s. ITNF was decreased by hyperpolarization and had a reversal potential of approximately -87 mV (close to the K+ equilibrium potential). Ion substitution and pharmacological experiments suggest that ITNF is due to a decreased K+ conductance and that TNF, a product of macrophages, may form an important link in communications between nervous and immune systems.
Sawada
M
M
Department of Physiology, Shimane Medical University, Izumo, Japan.
Hara
N
N
Maeno
T
T
D000818:Animals; D001048:Aplysia / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D011188:Potassium