Odor Stimuli Trigger Influx of Calcium Into Olfactory Neurons of the Channel Catfish

Restrepo, Diego; Miyamoto, Terumasa; Bryant, Bruce P.; Teeter, John H.

doi:10.1126/science.2168580

Cited by 280 publications

(153 citation statements)

References 35 publications

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“…The present work reveals that salamander ORNs are also advantageous for the analysis of Ca 2ϩ signals in olfactory cilia. Thus, although previous studies have shown cytoplasmic Ca 2ϩ responses in cell bodies and dendrites of ORNs from rat (Restrepo et al, 1993b;Tareilus et al, 1995), mouse (Sato et al, 1994), man (Restrepo et al, 1993a), catfish (Restrepo et al, 1990;Restrepo and Boyle, 1991), newt (Nakamura et al, 1994), or frog (Sato et al, 1991;Lischka and Schild, 1993), this is the first to demonstrate Ca 2ϩ transients within the ORN cilia.…”

Section: Calcium Imaging Of Salamander Olfactory Ciliamentioning

confidence: 55%

“…These studies detected elevations in [Ca 2ϩ ] i resulting from stimulation with single odor ligands or odor mixtures (Restrepo et al, 1990(Restrepo et al, , 1993aRestrepo and Boyle, 1991;Sato et al, 1991Sato et al, , 1994Nakamura et al, 1994;Tareilus et al, 1995), forskolin (Sato et al, 1991;Restrepo et al, 1993b), or dialysis of ORNs with cAMP (Nakamura et al, 1994) or IP 3 (Nakamura et al, 1994;Schild et al, 1995). Despite these abundant data, studies to date have not addressed Ca 2ϩ signals in the cilia, the site of odor transduction.…”

Section: Abstract: Olfactory Receptor Neurons; Cilia; Confocal Micromentioning

confidence: 99%

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Calcium Entry through Cyclic Nucleotide-Gated Channels in Individual Cilia of Olfactory Receptor Cells: Spatiotemporal Dynamics

et al. 1997

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Transient elevations of intracellular Ca 2ϩ play an important role in regulating the sensitivity of olfactory transduction, but such elevations have not been demonstrated in the olfactory cilia, which are the site of primary odor transduction. To begin to understand Ca 2ϩ signaling in olfactory cilia, we used highresolution imaging techniques to study the Ca 2ϩ transients that occur in salamander olfactory receptor neurons (ORNs) as a result of cyclic nucleotide-gated (CNG) channel activation. To visualize ciliary Ca 2ϩ signals, we loaded ORNs with the Ca 2ϩ indicator dye Fluo-3 AM and measured fluorescence with a laser scanning confocal microscope. Application of the phosphodiesterase inhibitor IBMX increased fluorescence in the cilia and other neuronal compartments; the ciliary signal occurred first and was more transient. This signal could be abolished by lowering external Ca 2ϩ or by applying LY83583, a potent blocker of CNG channels, indicating that Ca 2ϩ entry through CNG channels was the primary source of fluorescence increases. Direct activation of CNG channels with low levels of 8-Br-cGMP (1 M) led to tonic Ca 2ϩ signals that were restricted locally to the cilia and the dendritic knob. Elevated external K ϩ , which depolarizes cell membranes, increased fluorescence signals in the cell body and dendrite but failed to increase ciliary Ca 2ϩ fluorescence. The results demonstrate the existence and spatiotemporal properties of Ca 2ϩ transients in individual olfactory cilia and implicate CNG channels as a major pathway for Ca 2ϩ entry into ORN cilia during odor transduction.

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Section: Calcium Imaging Of Salamander Olfactory Ciliamentioning

confidence: 55%

Section: Abstract: Olfactory Receptor Neurons; Cilia; Confocal Micromentioning

confidence: 99%

Calcium Entry through Cyclic Nucleotide-Gated Channels in Individual Cilia of Olfactory Receptor Cells: Spatiotemporal Dynamics

et al. 1997

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“…The presence ofInsP3-gated channels in the outer dendrites strengthens the contention (21) that lobster ORNs in culture express the normal transduction machinery in the soma. Plasma membrane InsP3 receptors have also been implicated in olfactory transduction in catfish (9,28) and mammals (29,30).…”

Section: Resultsmentioning

confidence: 99%

Cyclic nucleotide- and inositol phosphate-gated ion channels in lobster olfactory receptor neurons.

Hatt

Ache

1994

Proc. Natl. Acad. Sci. U.S.A.

111

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The idea of having two second pathways In ofa , one mediated by cAMP aNd the other by bnosytol 1,4,5-trispbosphate, Is tation and inhibition of lobster ORNs are mediated by InsP3 and cAMP transduction cascades would be to demonstrate the presence of InsP3-and cAMP-activated ion channels at the presumed site of transduction, the outer dendritic membrane, in lobster ORNs in situ.Here, we report that cAMP and InsP3 applied to the inner face of cell-free patches of the outer dendritic membrane of lobster ORNs in situ directly activate distinct ion channels, that both types of second messenger-gated channels can occur in the same patch, and that the InsP3-gated channels, and possibly the cAMP-gated channels, can be one of two types. A preliminary description of these results has appeared (24).Odors are generally thought to activate olfactory receptor neurons (ORNs) through guanine nucleotide binding proteincoupled receptors that elicit rapid and transient pulses of intracellular second messengers (for reviews, see refs. 1-3). Attention has focused on two second messenger pathways, one mediated by cAMP and the other by inositol 1,4,5-trisphosphate (InsP3). cAMP and InsP3 olfactory transduction cascades have been identified in four groups of animals (mammals, refs. 4-6; amphibians, refs. 7 and 8; fish, refs. 9 and 10; crustaceans, refs. 11 (25), so the excised tips should contain only outer dendritic membrane and microtubules. Care was taken to include <50% of the length of the sensillum in the excised tips. Outer dendrites were placed in poly(D-lysine)-coated plastic dishes containing 5 ml of isolation buffer (460 mM

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“…Fax: (56) (2) 271-2983. E-mail: bacigalu@abello.dic.uchile.cl evidence for an odorant-induced Ca 2+ influx in olfactory cells [13]. An elevation of intracellular free Ca 2+ has been shown to be associated with odorant stimulation in fish [14], frog [15], rat [16,17] and human olfactory neurons [18].…”

Section: Introductionmentioning

confidence: 99%

Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons

1997

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In toad olfactory neurons, a putrid odorant mixture inducing inhibitory responses increases Ca 2+ -activated K + conductance, developing a hyperpolarizing receptor potential. Removal of extracellular Ca 2+ or exposure to nifedipine reversibly reduced the inhibitory response, suggesting that odorants induce a Ca 2+ influx. We show evidence for an odorant-induced Ca 2+ current. Using confocal microscopy, it is shown that odorants induce a nifedipine-sensitive elevation of Ca 2+ in the apical end of the cell. These results suggest an inhibitory mechanism in which an apical Ca 2+ influx causes an increase in internal Ca 2+ , opening Ca 2+ -activated K 2+ channels that lead to membrane hyperpolarization.

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Odor Stimuli Trigger Influx of Calcium Into Olfactory Neurons of the Channel Catfish

Cited by 280 publications

References 35 publications

Calcium Entry through Cyclic Nucleotide-Gated Channels in Individual Cilia of Olfactory Receptor Cells: Spatiotemporal Dynamics

Calcium Entry through Cyclic Nucleotide-Gated Channels in Individual Cilia of Olfactory Receptor Cells: Spatiotemporal Dynamics

Cyclic nucleotide- and inositol phosphate-gated ion channels in lobster olfactory receptor neurons.

Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons

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