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Cyclic Nucleotide‐gated Channels in Identified Human Olfactory Receptor Neurons
Author(s) -
Thüraüf N.,
Gjuric M.,
Kobal G.,
Hatt H.
Publication year - 1996
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1996.tb00729.x
Subject(s) - olfactory receptor , neuroscience , cyclic nucleotide gated ion channel , olfactory system , biology , genetics , cyclic nucleotide , nucleotide , gene
Patch‐clamp recordings revealed the presence of a non‐desensitizing cyclic nucleotide‐gated channel on human olfactory receptor neurons and a fast‐desensitizing non‐specific cation channel activated by nucleotides on human supporting cells. Cyclic nucleotide‐gated channels on olfactory receptor neurons showed selective channel activation by cAMP (K 1/2 = 5 μM) and cGMP (K 1/2 = 2 μM), a unitary conductance of ∼20 pS, a reversal potential of single‐channel currents close to 0 mV, a linear current‐voltage relationship over the range of −80 to 80 mV and a strong extracellular but a weaker intracellular blocking effect of Ca 2+ . The channel activity outlasted the cyclic nucleotide pulses for hundreds of milliseconds when higher agonist concentrations (>50 μM cAMP) were applied. The duration of the response was longer than in cyclic nucleotide‐gated channels from other species studied so far. The plateau duration and the decay remained constant for pulses with a length of 50−150 ms, whereas pulses shorter than 50 ms successively reduced the time required by shortening the plateau phase. A larger difference for the K 1/2 values of cAMP (K 1/2 = 22 μM) and cGMP (K 1/2 = 2.5 μM) were found for a small group (n = 3) of cyclic nucleotide‐gated channels, pointing to the selective expression of the a‐subunit in a small subgroup of olfactory receptor neurons.