scholarly journals Calcium-activated chloride current amplifies the response to urine in mouse vomeronasal sensory neurons

2009 ◽  
Vol 135 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Chun Yang ◽  
Rona J. Delay
Keyword(s):  
Sensory Neurons ◽  
Detection System ◽  
Reversal Potential ◽  
Vomeronasal Organ ◽  
Channel Blockers ◽  
Cl Channel ◽  
Chloride Accumulation ◽  
Perforated Patch Clamp ◽  
Whole Cell Recordings ◽  
Vomeronasal Sensory Neurons

The vomeronasal organ (VNO) is an odor detection system that mediates many pheromone-sensitive behaviors. Vomeronasal sensory neurons (VSNs), located in the VNO, are the initial site of interaction with odors/pheromones. However, how an individual VSN transduces chemical signals into electrical signals is still unresolved. Here, we show that a Ca2+-activated Cl− current contributes ∼80% of the response to urine in mouse VSNs. Using perforated patch clamp recordings with gramicidin, which leaves intracellular chloride undisrupted, we found that the urine-induced inward current (Vhold = −80 mV) was decreased in the presence of chloride channel blockers. This was confirmed using whole cell recordings and altering extracellular chloride to shift the reversal potential. Further, the urine-induced currents were eliminated when both extracellular Ca2+ and Na+ were removed. Using inside-out patches from dendritic tips, we recorded Ca2+-activated Cl− channel activity. Several candidates for this Ca2+-activated Cl− channel were detected in VNO by reverse transcription–polymerase chain reaction. In addition, a chloride cotransporter, Na+-K+-2Cl− isoform 1, was detected and found to mediate much of the chloride accumulation in VSNs. Collectively, our data demonstrate that chloride acts as a major amplifier for signal transduction in mouse VSNs. This amplification would increase the responsiveness to pheromones or odorants.

scholarly journals Conditional knockout of TMEM16A/anoctamin1 abolishes the calcium-activated chloride current in mouse vomeronasal sensory neurons

2015 ◽  
Vol 145 (4) ◽  
pp. 285-301 ◽  
Author(s):  
Asma Amjad ◽  
Andres Hernandez-Clavijo ◽  
Simone Pifferi ◽  
Devendra Kumar Maurya ◽  
Anna Boccaccio ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Functional Characterization ◽  
Vomeronasal Organ ◽  
Conditional Knockout ◽  
Channel Blockers ◽  
Whole Cell ◽  
Knock Out ◽  
Cl Channels ◽  
Inside Out ◽  
Vomeronasal Sensory Neurons

Pheromones are substances released from animals that, when detected by the vomeronasal organ of other individuals of the same species, affect their physiology and behavior. Pheromone binding to receptors on microvilli on the dendritic knobs of vomeronasal sensory neurons activates a second messenger cascade to produce an increase in intracellular Ca2+ concentration. Here, we used whole-cell and inside-out patch-clamp analysis to provide a functional characterization of currents activated by Ca2+ in isolated mouse vomeronasal sensory neurons in the absence of intracellular K+. In whole-cell recordings, the average current in 1.5 µM Ca2+ and symmetrical Cl− was −382 pA at −100 mV. Ion substitution experiments and partial blockade by commonly used Cl− channel blockers indicated that Ca2+ activates mainly anionic currents in these neurons. Recordings from inside-out patches from dendritic knobs of mouse vomeronasal sensory neurons confirmed the presence of Ca2+-activated Cl− channels in the knobs and/or microvilli. We compared the electrophysiological properties of the native currents with those mediated by heterologously expressed TMEM16A/anoctamin1 or TMEM16B/anoctamin2 Ca2+-activated Cl− channels, which are coexpressed in microvilli of mouse vomeronasal sensory neurons, and found a closer resemblance to those of TMEM16A. We used the Cre–loxP system to selectively knock out TMEM16A in cells expressing the olfactory marker protein, which is found in mature vomeronasal sensory neurons. Immunohistochemistry confirmed the specific ablation of TMEM16A in vomeronasal neurons. Ca2+-activated currents were abolished in vomeronasal sensory neurons of TMEM16A conditional knockout mice, demonstrating that TMEM16A is an essential component of Ca2+-activated Cl− currents in mouse vomeronasal sensory neurons.

Biophysical and pharmacological characterization of chloride currents in human astrocytoma cells

1996 ◽  
Vol 270 (5) ◽  
pp. C1511-C1521 ◽  
Author(s):  
N. Ullrich ◽  
H. Sontheimer
Keyword(s):  
Primary Cultures ◽  
Growth Control ◽  
Reversal Potential ◽  
Disulfonic Acid ◽  
Equilibrium Potential ◽  
Channel Blockers ◽  
Pharmacological Characterization ◽  
Cl Channel ◽  
Astrocytoma Cells ◽  
Human Astrocytoma

Expression of voltage-activated ion channels was studied in primary cultures from seven freshly resected human primary brain tumors and in an established human astrocytoma cell line, STTG1. Astrocytoma cells consistently expressed voltage-dependent outwardly rectifying currents. Currents activated at potentials > 45 mV and showed outward transients on termination of voltage steps. Currents reversed at the Cl equilibrium potential, suggesting that they were largely carried by Cl-. Altering extracellular K- or Na+ concentration did not alter currents; neither did replacement of intracellular K+ by Cs+ or intracellular Na+ by N-methyl-D-glucosamine. Anion-substitution experiments suggest the following permeability sequence, determined from shifts in tail current reversal potential: I- > NO3- > Br- > Cl- > acetate > isethionate > F- > glutamate. Currents were sensitive to the Cl- channel blockers chlorotoxin, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), and 4,4'-dinitrostilbene-2,2' disulfonic acid (DNDS), with chlorotoxin being most effective, yielding > 80% block at 590 nM. DIDS (100 microM) and DNDS (100 microM) reduced currents by 33.5 and 38.2%, respectively. Currents were also sensitive to Zn2+ (100 microM, 47% block) and Cd2- (25 microM, 42% block). Reducing extracellular Ca2+ concentration decreased outward currents by 58% and almost completely eliminated transients, suggesting that Cl- currents are Ca2+ dependent. Cl channel block resulted in altered cell proliferation as determined by [3H]thymidine incorporation, suggesting that these channels may be involved in astrocytoma growth control.

Glutamate-gated chloride channel with glutamate-transporter-like properties in cone photoreceptors of the tiger salamander

1995 ◽  
Vol 74 (4) ◽  
pp. 1760-1771 ◽  
Author(s):  
S. A. Picaud ◽  
H. P. Larsson ◽  
G. B. Grant ◽  
H. Lecar ◽  
F. S. Werblin
Keyword(s):  
Single Channel ◽  
Noise Analysis ◽  
Glutamate Transporter ◽  
Reversal Potential ◽  
Equilibrium Potential ◽  
Channel Blockers ◽  
Cone Photoreceptors ◽  
Patch Clamp Technique ◽  
Cl Channel ◽  
Open Time

1. Using the patch-clamp technique, we investigated whether the glutamate-elicited current in mechanically isolated cone photoreceptors from the salamander retina is generated by a Cl- channel or a glutamate transporter. 2. The current reversed near the equilibrium potential for Cl-, was decreased by three Cl- channel blockers, 5-nitro-2-(3-phenyl-propylamino) benzoic acid, 4,4'-diisothiocyanostilbene-2,2'-disulfonate, and diphenylamine 2,2'-dicarboxylic acid, and was eliminated when gluconate was substituted for both internal and external Cl-, features consistent with the current being mediated by a Cl- channel. 3. The single-channel conductance of the Cl- channel was estimated by noise analysis of the glutamate-elicited current fluctuations to be 0.7 pS with an open time of 2 ms. 4. The magnitude of the current was dependent on both internal and external Na+ and K+, features consistent with the current being related to the activation of a glutamate transporter. Yet changes in their concentrations did not affect the reversal potential of the current. 5. Taken together with earlier reports on this current showing that it has a glutamate-transporter-like pharmacology, our results suggest that the glutamate-elicited current is carried by a Cl- channel but gated by a glutamate receptor whose pharmacology and ionic requirement resemble those previously described for glutamate transporters.

scholarly journals The transcription factor Tfap2e/AP-2ε plays a pivotal role in maintaining the identity of basal vomeronasal sensory neurons

2018 ◽  
Author(s):  
Jennifer M Lin ◽  
Ed Zandro M Taroc ◽  
Jesus A Frias ◽  
Aparna Prasad ◽  
Allison N Catizone ◽  
...  
Keyword(s):  
Transcription Factor ◽  
G Protein ◽  
Sensory Neurons ◽  
Control Cell ◽  
Neuronal Cell ◽  
Vomeronasal Organ ◽  
Cell Types ◽  
Protein Subunit ◽  
Cell Type Specific ◽  
Vomeronasal Sensory Neurons

The identity of individual neuronal cell types is defined by the expression of specific combinations of transcriptional regulators that control cell type-specific genetic programs. The epithelium of the vomeronasal organ of mice contains two major types of vomeronasal sensory neurons (VSNs): 1) the apical VSNs which express vomeronasal 1 receptors (V1r) and the G-protein subunit Gαi2 and; 2) the basal VSNs which express vomeronasal 2 receptors (V2r) and the G-protein subunit Gαo. Both cell types originate from a common pool of progenitors and eventually acquire apical or basal identity through largely unknown mechanisms. The transcription factor AP-2ε, encoded by the Tfap2e gene, plays a role in controlling the development of GABAergic interneurons in the main and accessory olfactory bulb (AOB), moreover AP-2ε has been previously described to be expressed in the VSNs. Here we show that AP-2ε is expressed in postmitotic VSNs after they commit to the basal differentiation program. Loss of AP-2ε function resulted in reduced number of basal VSNs and in an increased number of neurons expressing markers of the apical lineage. Our work suggests that AP-2ε, which is expressed in late phases of differentiation, is not needed to initiate the apical-basal differentiation dichotomy but for maintaining the basal VSNs' identity by preventing the expression of apical genes. Moreover, our data suggest that differentiated VSNs of mice retain a notable level of plasticity.

scholarly journals Smad4 signaling establishes the somatosensory map of basal vomeronasal sensory neurons

2019 ◽  
Author(s):  
Ankana S. Naik ◽  
Jennifer M. Lin ◽  
Ed Zandro M. Taroc ◽  
Raghu R. Katreddi ◽  
Jesus A. Frias ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Critical Role ◽  
Vomeronasal Organ ◽  
Bmp Signaling ◽  
Loss Of Function ◽  
Neuronal Populations ◽  
Innervation Patterns ◽  
Circuit Formation ◽  
Accessory Olfactory System ◽  
Vomeronasal Sensory Neurons

SummaryThe accessory olfactory system is a unique model that can give insights on how the neurons can establish and maintain their identity, and connectivity. The vomeronasal organ (VNO) contains two distinct populations of vomeronasal sensory neurons (VSNs) each with specific innervation patterns to the accessory olfactory bulb (AOB). Though morphogenic signals are critical in defining various neuronal populations, the morphogenic signaling profiles that influence each VSN population remains unknown. Here, we found a pronounced BMP signaling gradient within the basal VSNs. By generating Smad4 conditional mutants, we disrupted canonical TGF-β/BMP signaling in maturing basal VSNs and in all mature VSNs. We show that Smad4 loss-of-function in immature basal neurons leads to a progressive loss of basal VSNs, reduced activation of the remnant basal VSNs, and aberrant glomeruli formation in posterior AOB. However, Smad4 ablation in all mature VSNs does not affect neuronal activity nor survival but causes aberrant glomeruli formation only in the posterior AOB. Our study reveals that Smad4 signaling plays a critical role in mediating development, function, and circuit formation of basal VSNs.

scholarly journals Central role of G protein Gαi2 and Gαi2+ vomeronasal neurons in balancing territorial and infant-directed aggression of male mice

2019 ◽  
Vol 116 (11) ◽  
pp. 5135-5143 ◽  
Author(s):  
Anne-Charlotte Trouillet ◽  
Matthieu Keller ◽  
Jan Weiss ◽  
Trese Leinders-Zufall ◽  
Lutz Birnbaumer ◽  
...  
Keyword(s):  
G Protein ◽  
Sensory Neurons ◽  
Neural Activity ◽  
Parental Behavior ◽  
Vomeronasal Organ ◽  
Male Infant ◽  
Lateral Septum ◽  
Male Mice ◽  
Protein Subunit ◽  
Α Subunit

Aggression is controlled by the olfactory system in many animal species. In male mice, territorial and infant-directed aggression are tightly regulated by the vomeronasal organ (VNO), but how diverse subsets of sensory neurons convey pheromonal information to limbic centers is not yet known. Here, we employ genetic strategies to show that mouse vomeronasal sensory neurons expressing the G protein subunit Gαi2 regulate male–male and infant-directed aggression through distinct circuit mechanisms. Conditional ablation of Gαi2 enhances male–male aggression and increases neural activity in the medial amygdala (MeA), bed nucleus of the stria terminalis, and lateral septum. By contrast, conditional Gαi2 ablation causes reduced infant-directed aggression and decreased activity in MeA neurons during male–infant interactions. Strikingly, these mice also display enhanced parental behavior and elevated neural activity in the medial preoptic area, whereas sexual behavior remains normal. These results identify Gαi2 as the primary G protein α-subunit mediating the detection of volatile chemosignals in the apical layer of the VNO, and they show that Gαi2+ VSNs and the brain circuits activated by these neurons play a central role in orchestrating and balancing territorial and infant-directed aggression of male mice through bidirectional activation and inhibition of different targets in the limbic system.

Whole cell current analyses of pancreatic acinar AR42J cells. I. Voltage- and Ca(2+)-activated currents

1991 ◽  
Vol 260 (5) ◽  
pp. C934-C948 ◽  
Author(s):  
K. Kusano ◽  
H. Gainer
Keyword(s):  
Reversal Potential ◽  
Outward Current ◽  
Pancreatic Acinar Cells ◽  
Equilibrium Potential ◽  
Channel Blockers ◽  
Whole Cell ◽  
Inward Current ◽  
Tail Current ◽  
Ar42j Cells ◽  
Conductance Increase

Voltage- and Ca(2+)-activated whole cell currents were studied in AR42J cells, a clonal cell line derived from rat pancreatic acinar cells, using a patch electrode voltage-clamp technique. Four kinds of ionic currents were identified by their ionic dependencies, pharmacological properties, and kinetic parameters: 1) an outward current flow due mainly to a voltage-dependent K(+)-conductance increase, 2) an initial transient inward current due to an Na(+)-conductance increase, 3) transient and long-duration inward current due to a Ca(2+)-conductance increase, and 4) a slowly activating inward current that persists over the duration of the depolarizing pulse and deactivates slowly upon repolarization, producing a slow inward tail current. The slow inward tail current was particularly robust and was interpreted as due to a Ca(2+)-activated Cl(-)-conductance increase, since 1) the generation of this current was blocked by removing the extracellular Ca2+, applying Ca(2+)-channel blockers (Cd2+, nifedipine), or by lowering the intracellular Ca2+ concentration [( Ca2+]i) with EGTA; and 2) the reversal potential (Erev) of the slow inward tail current was close to 0 mV in the control condition (152 mM [Cl-]o/154 mM [Cl-]i), and changes of the [Cl-]o/[Cl )i ratio shifted the Erev toward the predicted Cl- equilibrium potential.

Characterization of the human pH- and PKA-activated ClC-2G(2 alpha) Cl- channel

1997 ◽  
Vol 273 (2) ◽  
pp. C384-C393 ◽  
Author(s):  
A. M. Sherry ◽  
K. Stroffekova ◽  
L. M. Knapp ◽  
E. Y. Kupert ◽  
J. Cuppoletti ◽  
...  
Keyword(s):  
Human Lung ◽  
Single Channel ◽  
Reversal Potential ◽  
Fetal Lung ◽  
Northern Analysis ◽  
Adult Human ◽  
Cl Channel ◽  
Voltage Curve ◽  
Current Voltage Curve ◽  
Adult Human Lung

A ClC-2G(2 alpha) Cl- channel was identified to be present in human lung and stomach, and a partial cDNA for this Cl- channel was cloned from a human fetal lung library. A full-length expressible human ClC-2G(2 alpha) cDNA was constructed by ligation of mutagenized expressible rabbit ClC-2G(2 alpha) cDNA with the human lung ClC-2G(2 alpha) cDNA, expressed in oocytes, and characterized at the single-channel level. Adenosine 3',5'-cyclic monophosphate-dependent protein kinase (PKA) treatment increased the probability of opening of the channel (Po). After PKA activation, the channel exhibited a linear (r = 0.99) current-voltage curve with a slope conductance of 22.1 +/- 0.8 pS in symmetric 800 mM tetraethylammonium chloride (TEACl; pH 7.4). Under fivefold gradient conditions of TEACl, a reversal potential of +21.5 +/- 2.8 mV was measured demonstrating anion-to-cation discrimination. As previously demonstrated for the rabbit ClC-2G(2 alpha) Cl- channel, the human analog, hClC-2G(2 alpha), was active at pH 7.4 as well as when the pH of the extracellular face of the channel (trans side of the bilayer; pHtrans) was asymmetrically reduced to pH 3.0. The extent of PKA activation was dependent on pHtrans. With PKA treatment, Po increased fourfold with a pHtrans of 7.4 and eightfold with a pHtrans of 3.0. Effects of sequential PKA addition followed by pHtrans reduction on the same channel suggested that the PKA- and pH-dependent increases in channel Po were separable and cumulative. Northern analysis showed ClC-2G(2 alpha) mRNA to be present in human adult and fetal lung and adult stomach, and quantitative reverse transcriptase-polymerase chain reaction showed this channel to be present in the adult human lung and stomach at about one-half the level found in fetal lung. The findings of the present study suggest that the ClC-2G(2 alpha) Cl- channel may play an important role in Cl- transport in the fetal and adult human lung.

scholarly journals Conditional knockout of TMEM16A/anoctamin1 abolishes the calcium-activated chloride current in mouse vomeronasal sensory neurons

2015 ◽  
Vol 212 (5) ◽  
pp. 2125OIA23
Author(s):  
Asma Amjad ◽  
Andres Hernandez-Clavijo ◽  
Simone Pifferi ◽  
Devendra Kumar Maurya ◽  
Anna Boccaccio ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Conditional Knockout ◽  
Chloride Current ◽  
Vomeronasal Sensory Neurons

scholarly journals Maternally inherited peptides as strain-specific chemosignals

2020 ◽  
Vol 117 (48) ◽  
pp. 30738-30743
Author(s):  
Hideto Kaba ◽  
Hiroko Fujita ◽  
Takeshi Agatsuma ◽  
Hiroaki Matsunami
Keyword(s):  
Sensory Neurons ◽  
Individual Recognition ◽  
Vomeronasal Organ ◽  
Mate Recognition ◽  
Inbred Strains ◽  
Specific Information ◽  
Maternal Lineage ◽  
Maternal Bonding ◽  
Terminal Amino ◽  
Nadh Dehydrogenases

Most mammals rely on chemosensory cues for individual recognition, which is essential to many aspects of social behavior, such as maternal bonding, mate recognition, and inbreeding avoidance. Both volatile molecules and nonvolatile peptides secreted by individual conspecifics are detected by olfactory sensory neurons in the olfactory epithelium and the vomeronasal organ. The pertinent cues used for individual recognition remain largely unidentified. Here we show that nonformylated, but notN-formylated, mitochondrially encoded peptides—that is, the nine N-terminal amino acids of NADH dehydrogenases 1 and 2—can be used to convey strain-specific information among individual mice. We demonstrate that these nonformylated peptides are sufficient to induce a strain-selective pregnancy block. We also observed that the pregnancy block by an unfamiliar peptide derived from a male of a different strain was prevented by a memory formed at the time of mating with that male. Our findings also demonstrate that pregnancy-blocking chemosignals in the urine are maternally inherited, as evidenced by the production of reciprocal sons from two inbred strains and our test of their urine’s ability to block pregnancy. We propose that this link between polymorphic mitochondrial peptides and individual recognition provides the molecular means to communicate an individual’s maternal lineage and strain.

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