RT Journal Article
SR Electronic
T1 Calcium-activated chloride conductance in frog olfactory cilia
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 3624
OP 3629
DO 10.1523/JNEUROSCI.11-11-03624.1991
VO 11
IS 11
A1 SJ Kleene
A1 RC Gesteland
YR 1991
UL http://www.jneurosci.org/content/11/11/3624.abstract
AB We have measured the effects of cytoplasmic Ca2+ on the conductance of single cilia excised from frog olfactory receptor neurons. When free cytoplasmic Ca2+ is buffered at 0.1 microM, ciliary conductance is low. As Ca2+ is increased, ciliary conductance increases. Maximal conductance averages sevenfold higher than that measured in the absence of Ca2+. We estimate that the K1/2 for Ca2+ activation is 5 microM; the dose-response curve indicates some positive cooperativity of Ca2+ binding. Activation by Ca2+ is rapid and fully reversible. Most of the Ca(2+)-activated current is carried by Cl- and persists in the absence of Na+ and K+. The Cl- channel inhibitor 3′,5-dichlorodiphenylamine-2- carboxylate (300 microM) reduces the Ca(2+)-activated current by 90%. Odorants induce a Ca2+ influx in some olfactory receptor neurons, but the consequences of this influx for neuronal function are not well understood. Our findings allow us to predict that a Ca2+ influx would increase the permeability of the olfactory cilia to Cl-. How this would affect the neuronal potential is uncertain, since the equilibrium potential for Cl- in olfactory receptor neurons is unknown.