title: Ionic conductances in sustentacular cells of the mouse olfactory epithelium.
abstract: The electrical properties of sustentacular cells (SCs) in the olfactory epithelium (OE) were investigated in tissue slices taken from neonatal mice (P0-P4). Conventional whole-cell recordings were obtained from SCs and also from olfactory receptor neurones (ORNs) in situ. SCs had a larger apparent cell capacitance (C(cell)) (18.6 +/- 0.5 pF) than ORNs (4.4 +/- 0.4 pF) and a lower apparent membrane resistance (R(m)) (160 +/- 11 MOmega versus 664 +/- 195 MOmega, respectively). When corrected for a seal resistance of 1 GOmega, these mean R(m) values were increased to 190 MOmega and 2 GOmega in SCs and ORNs, respectively. SCs generated a TTX (1 microm)-resistant voltage-activated Na(+) current (I(Na)) that had a peak density at -38 mV of -44 pA pF(-1) and supported action potential firing. Peak current density of I(Na) in neurones was 510 +/- 96 pA pF(-1). The outward K(+) current in SCs was composed (> 70%) of a TEA (2 mm)-sensitive component that was mediated by the opening of large-conductance (237 +/- 10 pS; BK) channels. The resting leak conductance (g(L)) of SCs was permeable to monovalent cations and anions and was largely inhibited by substitution of external Na(+) with NMDG and by internal F(-) with gluconate. g(L) deactivated up to 50% at potentials negative of -70 mV and was inhibited by 18beta-glycyrrhetinic acid (20 mum). SCs were identified using fluorescent dyes (Lucifer Yellow and Alexa Fluor 488) in the whole-cell patch pipette-filling solution. Our findings indicate that SCs in the OE of neonates are electrically excitable and are distinguishable from neurones by a having a resting g(L).
authors.affiliation: Department of Physiology, University of Utah, 410 Chipeta Way, Room 156, Salt Lake City, UT 84108-1297, USA.
authors.forename: Fivos
authors.initials: F
authors.lastname: Vogalis
authors.forename: Colleen C
authors.initials: CC
authors.lastname: Hegg
authors.forename: Mary T
authors.initials: MT
authors.lastname: Lucero
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002462:Cell Membrane / Q000502:physiology* / Q000648:ultrastructure*; D002478:Cells, Cultured; D004553:Electric Conductivity; D015640:Ion Channel Gating / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D009831:Olfactory Mucosa / Q000166:cytology* / Q000502:physiology*; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
chemical_list: D012964:Sodium; D011188:Potassium