title: Voltage-sensitive chloride ion channels in Anopheles gambiae Sua-1B cells.
abstract: In this study, we performed electrophysiological analysis of Anopheles gambiae Sua-1B cells having "neuron-like" morphologies using the patch clamp method. The recorded cells (n = 79) had processes resembling axons/dendrites, with 63 % unipolar, 22 % bipolar, and 15 % multipolar. While no inward currents were observed following step depolarizations (holding potential = -80 mV), a slowly activating outward current was observed in 96 % of the cells, especially at depolarized potentials. The amplitude of the current was attenuated nearly 70 % by reducing extracellular Cl⁻ ion concentration, or by incubating with 100 μM DIDS, a known voltage-sensitive chloride channel blocker, suggesting that the current was mediated by chloride ions. No qualitative difference was found between recordings made with Cs⁺ ions in the intracellular pipette solution (inhibits K⁺ currents) and those made with normal physiological solution, indicating a deficiency of potassium channels. Additionally, recordings made with Ca²⁺-free extracellular bath solution eliminated the slowly activating outward current. A subset of cells (n = 3) lacked this current, but had outward currents with voltage-dependent properties similar to those of volume-regulated chloride channels. Taken together, our results suggest that the voltage-sensitive currents observed in the majority of Sua-1B cells are mediated primarily by chloride channels of the calcium-dependent subtype.
authors.affiliation: Department of Entomology and Nematology, Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, PO Box 100009, Gainesville, FL 32610-00009, USA.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Diykov
authors.forename: Lacey J
authors.initials: LJ
authors.lastname: Jenson
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Bloomquist
mesh_terms: D000818:Animals; D000852:Anopheles / Q000502:physiology*; D002460:Cell Line; D018118:Chloride Channels / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques
chemical_list: D018118:Chloride Channels