An odorant-suppressed Cl - conductance in lobster olfactory receptor cells

Odorants evoke an outward current in cultured lobster olfactory receptor neurons voltage clamped at –60 mV. The reversal potential of the outward current is independent of the reversal potential of potassium, but shifts with imposed changes in the reversal potential of chloride. The slope of the cur...

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Bibliographic Details
Published in:Journal of Comparative Physiology 2001-07, Vol.187 (6), p.477-487
Main Authors: Doolin, Richard, Zhainazarov, Asylbek, Ache, Barry
Format: Article
Language:English
Subjects:
Anthracene
Aroma compounds
Carboxylic acids
Chloride
Chloride conductance
Chlorides
Dendrites
Electric potential
Membrane conductance
Neurons
Nose
Odorant receptors
Odorants
Olfactory receptor neurons
Potassium
Potassium conductance
Steady state
Voltage
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Summary:Odorants evoke an outward current in cultured lobster olfactory receptor neurons voltage clamped at –60 mV. The reversal potential of the outward current is independent of the reversal potential of potassium, but shifts with imposed changes in the reversal potential of chloride. The slope of the current-voltage relationship is negative, suggesting that the current is mediated by the odorant suppressing a steady-state conductance. Anthracene-9-carboxylic acid, a specific chloride channel blocker, reversibly inhibits the steady-state conductance. Local application of odorants to the outer dendrites evokes a hyperpolarizing receptor potential in lobster olfactory receptor neurons current-clamped at –70 mV in situ. Consistent with the current characterized in the cultured cells, hyperpolarizing receptor potentials in some cells are voltage sensitive, blocked by anthracene-9-carboxylic acid and associated with a decrease in membrane conductance. These results support the hypothesis that odorants suppress a steady-state chloride conductance in lobster olfactory receptor neurons. Evidence that the chloride conductance can coexist with a 4-aminopyridine-blockable potassium conductance reported earlier in these cells suggests that two distinct mechanisms can mediate odorant-evoked inhibition in lobster olfactory receptor neurons.
ISSN:0340-7594
1432-1351
DOI:10.1007/s003590100217