scholarly journals Calcium-activated chloride channels in the apical region of mouse vomeronasal sensory neurons

2012 ◽  
Vol 140 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Michele Dibattista ◽  
Asma Amjad ◽  
Devendra Kumar Maurya ◽  
Claudia Sagheddu ◽  
Giorgia Montani ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Chloride Channels ◽  
Calcium Concentration ◽  
Transient Receptor Potential ◽  
Flash Photolysis ◽  
Physiological Role ◽  
Disulfonic Acid ◽  
Apical Region ◽  
Caged Calcium ◽  
Vomeronasal Sensory Neurons

The rodent vomeronasal organ plays a crucial role in several social behaviors. Detection of pheromones or other emitted signaling molecules occurs in the dendritic microvilli of vomeronasal sensory neurons, where the binding of molecules to vomeronasal receptors leads to the influx of sodium and calcium ions mainly through the transient receptor potential canonical 2 (TRPC2) channel. To investigate the physiological role played by the increase in intracellular calcium concentration in the apical region of these neurons, we produced localized, rapid, and reproducible increases in calcium concentration with flash photolysis of caged calcium and measured calcium-activated currents with the whole cell voltage-clamp technique. On average, a large inward calcium-activated current of −261 pA was measured at −50 mV, rising with a time constant of 13 ms. Ion substitution experiments showed that this current is anion selective. Moreover, the chloride channel blockers niflumic acid and 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid partially inhibited the calcium-activated current. These results directly demonstrate that a large chloride current can be activated by calcium in the apical region of mouse vomeronasal sensory neurons. Furthermore, we showed by immunohistochemistry that the calcium-activated chloride channels TMEM16A/anoctamin1 and TMEM16B/anoctamin2 are present in the apical layer of the vomeronasal epithelium, where they largely colocalize with the TRPC2 transduction channel. Immunocytochemistry on isolated vomeronasal sensory neurons showed that TMEM16A and TMEM16B coexpress in the neuronal microvilli. Therefore, we conclude that microvilli of mouse vomeronasal sensory neurons have a high density of calcium-activated chloride channels that may play an important role in vomeronasal transduction.

scholarly journals P2Y2 receptors mediate ATP-induced resensitization of TRPV1 expressed by kidney projecting sensory neurons

2010 ◽  
Vol 298 (6) ◽  
pp. R1634-R1641 ◽  
Author(s):  
Hui Wang ◽  
Donna H. Wang ◽  
James J. Galligan
Keyword(s):  
Sensory Neurons ◽  
Receptor Agonist ◽  
Pyridoxal Phosphate ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
P2y Receptors ◽  
Receptor Activation ◽  
Sensory Nerves ◽  
Disulfonic Acid ◽  
Transient Receptor Potential Vanilloid

The transient receptor potential vanilloid type 1 (TRPV1) channel is a ligand-gated cation channel expressed by sensory nerves. P2Y receptors are G protein-coupled receptors that are also expressed by TRPV1-positive sensory neurons. Therefore, we studied interactions between P2Y receptors and TRPV1 function on kidney projecting sensory neurons. Application of Fast Blue (FB) to nerves surrounding the renal artery retrogradely labeled neurons in dorsal root ganglia of rats. Whole cell recording was performed on FB-labeled neurons maintained in primary culture. Capsaicin was used to activate TRPV1. Four types of kidney projecting neurons were identified based on capsaicin responses: 1) desensitizing (35%), 2) nondesensitizing (29%), 3) silent (3%), and 4) insensitive (30%). Silent neurons responded to capsaicin only after ATP (100 μM) pretreatment. ATP reversed desensitization in desensitizing neurons. Insensitive neurons never responded to capsaicin. UTP, a P2Y purinoceptor 2 (P2Y2)/P2Y4 receptor agonist, reversed capsaicin-induced TRPV1 desensitization. 2-methyl-thio-ATP (2-Me-S-ATP), a P2Y1 receptor agonist, did not change desensitization. MRS 2179 and pyridoxal-phosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS), drugs that block P2Y1 receptors, did not block ATP-induced resensitization of TRPV1. Suramin, a P2Y2 receptor antagonist, blocked resensitization caused by UTP. Immunocytochemical studies showed that FB-labeled neurons coexpressed P2Y2 receptors and TRPV1. We conclude that P2Y2 receptor activation can maintain TRPV1 function perhaps during sustained episodes of activity of kidney projecting sensory neurons.

scholarly journals Fast Adaptation in Mouse Olfactory Sensory Neurons Does Not Require the Activity of Phosphodiesterase

2006 ◽  
Vol 128 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Anna Boccaccio ◽  
Laura Lagostena ◽  
Volker Hagen ◽  
Anna Menini
Keyword(s):  
Sensory Neurons ◽  
Molecular Mechanisms ◽  
Flash Photolysis ◽  
Physiological Role ◽  
Reversal Potential ◽  
Cell Voltage ◽  
Olfactory Sensory Neurons ◽  
Cng Channel ◽  
Ion Substitution ◽  
Fast Adaptation

Vertebrate olfactory sensory neurons rapidly adapt to repetitive odorant stimuli. Previous studies have shown that the principal molecular mechanisms for odorant adaptation take place after the odorant-induced production of cAMP, and that one important mechanism is the negative feedback modulation by Ca2+-calmodulin (Ca2+-CaM) of the cyclic nucleotide-gated (CNG) channel. However, the physiological role of the Ca2+-dependent activity of phosphodiesterase (PDE) in adaptation has not been investigated yet. We used the whole-cell voltage-clamp technique to record currents in mouse olfactory sensory neurons elicited by photorelease of 8-Br-cAMP, an analogue of cAMP commonly used as a hydrolysis-resistant compound and known to be a potent agonist of the olfactory CNG channel. We measured currents in response to repetitive photoreleases of cAMP or of 8-Br-cAMP and we observed similar adaptation in response to the second stimulus. Control experiments were conducted in the presence of the PDE inhibitor IBMX, confirming that an increase in PDE activity was not involved in the response decrease. Since the total current activated by 8-Br-cAMP, as well as that physiologically induced by odorants, is composed not only of current carried by Na+ and Ca2+ through CNG channels, but also by a Ca2+-activated Cl− current, we performed control experiments in which the reversal potential of Cl− was set, by ion substitution, at the same value of the holding potential, −50 mV. Adaptation was measured also in these conditions of diminished Ca2+-activated Cl− current. Furthermore, by producing repetitive increases of ciliary's Ca2+ with flash photolysis of caged Ca2+, we showed that Ca2+-activated Cl− channels do not adapt and that there is no Cl− depletion in the cilia. All together, these results indicate that the activity of ciliary PDE is not required for fast adaptation to repetitive stimuli in mouse olfactory sensory neurons.

Ca2+ release dynamics in parotid and pancreatic exocrine acinar cells evoked by spatially limited flash photolysis

2007 ◽  
Vol 293 (6) ◽  
pp. G1166-G1177 ◽  
Author(s):  
Jong Hak Won ◽  
William J. Cottrell ◽  
Thomas H. Foster ◽  
David I. Yule
Keyword(s):  
Latent Period ◽  
Wave Speed ◽  
Calcium Release ◽  
Flash Photolysis ◽  
Physiological Role ◽  
Acinar Cells ◽  
Apical Region ◽  
Cell Type ◽  
Fast Kinetics ◽  
Kinetics Of

Intracellular calcium concentration ([Ca2+]i) signals are central to the mechanisms underlying fluid and protein secretion in pancreatic and parotid acinar cells. Calcium release was studied in natively buffered cells following focal laser photolysis of caged molecules. Focal photolysis of caged-inositol 1,4,5 trisphosphate (InsP3) in the apical region resulted in Ca2+ release from the apical trigger zone and, after a latent period, the initiation of an apical-to-basal Ca2+ wave. The latency was longer and the wave speed significantly slower in pancreatic compared with parotid cells. Focal photolysis in basal regions evoked only limited Ca2+ release at the photolysis site and never resulted in a propagating wave. Instead, an apical-to-basal wave was initiated following a latent period. Again, the latent period was significantly longer under all conditions in pancreas than parotid. Although slower in pancreas than parotid, once initiated, the apical-to-basal wave speed was constant in a particular cell type. Photo release of caged-Ca2+ failed to evoke a propagating Ca2+ wave in either cell type. However, the kinetics of the Ca2+ signal evoked following photolysis of caged-InsP3 were significantly dampened by ryanodine in parotid but not pancreas, indicating a more prominent functional role for ryanodine receptor (RyR) following InsP3 receptor (InsP3R) activation. These data suggest that differing expression levels of InsP3R, RyR, and possibly cellular buffering capacity may contribute to the fast kinetics of Ca2+ signals in parotid compared with pancreas. These properties may represent a specialization of the cell type to effectively stimulate Ca2+-dependent effectors important for the differing primary physiological role of each gland.

scholarly journals Selective Induction of LTP and LTD by Postsynaptic [Ca2+]i Elevation

1999 ◽  
Vol 81 (2) ◽  
pp. 781-787 ◽  
Author(s):  
Shao-Nian Yang ◽  
Yun-Gui Tang ◽  
Robert S. Zucker
Keyword(s):  
Calcium Concentration ◽  
Pyramidal Cells ◽  
Long Term Potentiation ◽  
Biological Information ◽  
Synaptic Modulation ◽  
Ca1 Pyramidal Cells ◽  
Caged Calcium ◽  
Term Potentiation ◽  
Calcium Compound

Selective Induction of LTP and LTD by Postsynaptic [Ca2+]i Elevation. Long-term potentiation (LTP) and long-term depression (LTD), two prominent forms of synaptic plasticity at glutamatergic afferents to CA1 hippocampal pyramidal cells, are both triggered by the elevation of postsynaptic intracellular calcium concentration ([Ca2+]i). To understand how one signaling molecule can be responsible for triggering two opposing forms of synaptic modulation, different postsynaptic [Ca2+]i elevation patterns were generated by a new caged calcium compound nitrophenyl-ethylene glycol-bis(β-aminoethyl ether)- N, N, N′, N′-tetraacetic acid in CA1 pyramidal cells. We found that specific patterns of [Ca2+]i elevation selectively activate LTP or LTD. In particular, only LTP was triggered by a brief increase of [Ca2+]i with relatively high magnitude, which mimics the [Ca2+]i rise during electrical stimulation typically used to induce LTP. In contrast, a prolonged modest rise of [Ca2+]i reliably induced LTD. An important implication of the results is that both the amplitude and the duration of an intracellular chemical signal can carry significant biological information.

Protease-activated receptor-2 activation exaggerates TRPV1-mediated cough in guinea pigs

2006 ◽  
Vol 101 (2) ◽  
pp. 506-511 ◽  
Author(s):  
Raffaele Gatti ◽  
Eunice Andre ◽  
Silvia Amadesi ◽  
Thai Q. Dinh ◽  
Axel Fischer ◽  
...  
Keyword(s):  
Citric Acid ◽  
Sensory Neurons ◽  
Guinea Pigs ◽  
Transient Receptor Potential ◽  
Inflammatory Diseases ◽  
Receptor Potential ◽  
Chronic Obstructive ◽  
Transient Receptor Potential Vanilloid ◽  
Independent Manner ◽  
Protease Activated Receptor 2

A lowered threshold to the cough response frequently accompanies chronic airway inflammatory conditions. However, the mechanism(s) that from chronic inflammation results in a lowered cough threshold is poorly understood. Irritant agents, including capsaicin, resiniferatoxin, and citric acid, elicit cough in humans and in experimental animals through the activation of the transient receptor potential vanilloid 1 (TRPV1). Protease-activated receptor-2 (PAR2) activation plays a role in inflammation and sensitizes TRPV1 in cultured sensory neurons by a PKC-dependent pathway. Here, we have investigated whether PAR2 activation exaggerates TRPV1-dependent cough in guinea pigs and whether protein kinases are involved in the PAR2-induced cough modulation. Aerosolized PAR2 agonists (PAR2-activating peptide and trypsin) did not produce any cough per se. However, they potentiated citric acid- and resiniferatoxin-induced cough, an effect that was completely prevented by the TRPV1 receptor antagonist capsazepine. In contrast, cough induced by hypertonic saline, a stimulus that provokes cough in a TRPV1-independent manner, was not modified by aerosolized PAR2 agonists. The PKC inhibitor GF-109203X, the PKA inhibitor H-89, and the cyclooxygenase inhibitor indomethacin did not affect cough induced by TRPV1 agonists, but abated the exaggeration of this response produced by PAR2 agonists. In conclusion, PAR2 stimulation exaggerates TRPV1-dependent cough by activation of diverse mechanism(s), including PKC, PKA, and prostanoid release. PAR2 activation, by sensitizing TRPV1 in primary sensory neurons, may play a role in the exaggerated cough observed in certain airways inflammatory diseases such as asthma and chronic obstructive pulmonary disease.

scholarly journals Annexin A4 Reduces Water and Proton Permeability of Model Membranes but Does Not Alter Aquaporin 2–mediated Water Transport in Isolated Endosomes

2003 ◽  
Vol 121 (5) ◽  
pp. 413-425 ◽  
Author(s):  
Warren G. Hill ◽  
Marcia A. Kaetzel ◽  
Bellamkonda K. Kishore ◽  
John R. Dedman ◽  
Mark L. Zeidel
Keyword(s):  
Membrane Permeability ◽  
Water Permeability ◽  
Membrane Trafficking ◽  
Collecting Duct ◽  
Water Flux ◽  
Physiological Role ◽  
Apical Region ◽  
Proton Permeability ◽  
Aquaporin 2 ◽  
Annexin A4

Annexin A4 (Anx4) belongs to a ubiquitous family of Ca2+-dependent membrane-binding proteins thought to be involved in membrane trafficking and membrane organization within cells. Anx4 localizes to the apical region in epithelia; however, its physiological role is unclear. We show that Anx4 exhibited binding to liposomes (phosphatidylcholine:phosphatidylserine, 1:1) in the presence of Ca2+ and binding was reversible with EDTA. Anx4 binding resulted in liposome aggregation and a reduction in membrane water permeability of 29% (P < 0.001) at 25°C. These effects were not seen in the presence of Ca2+ or Anx4 alone and were reversible with EDTA. Measurements of membrane fluidity made by monitoring fluorescence anisotropy of 2-(12-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoyl-1-hexadecanoyl-sn-glycero-3-phosphocholine (NBD-HPC) demonstrated that Anx4 binding rigidified the outer leaflet of the bilayer (P < 0.001), thus providing a molecular explanation for the inhibition of water flux. To determine whether Anx4 would produce similar effects on physiological membranes we constructed liposomes which recapitulated the lipid composition of the inner leaflet of the MDCK apical membrane. These membranes exhibited reductions to water permeability upon Anx4 binding (19.5% at 25°C, 31% at 37°C; P < 0.01 and P < 0.001, respectively) and to proton permeability (15% at 25°C, 19.5% at 37°C; P < 0.05). Since our in vitro experiments indicated an effect on membrane permeability, we examined localization of Anx4 in the kidney collecting duct, a region of the nephron responsible for concentrating urine through water reabsorbtion. Anx4 was shown to colocalize apically with aquaporin 2 (AQP2) in collecting duct epithelia. To test for the existence of a functional interaction between Anx4 and AQP2 we isolated AQP2-containing endosomes and exposed them to Anx4/Ca2+. Water flux rates were unchanged, indicating Anx4 does not directly regulate AQP2. We conclude that Anx4 can alter the physical properties of membranes by associating with them and regulate passive membrane permeability to water and protons. These properties represent important new functions for Anx4.

scholarly journals Selective Expression of a SNARE-Cleaving Protease in Peripheral Sensory Neurons Attenuates Pain-Related Gene Transcription and Neuropeptide Release

2021 ◽  
Vol 22 (16) ◽  
pp. 8826
Author(s):  
Wanzhi Wang ◽  
Miaomiao Kong ◽  
Yu Dou ◽  
Shanghai Xue ◽  
Yang Liu ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Sensory Neurons ◽  
Transient Receptor Potential ◽  
Safety Concern ◽  
Unmet Need ◽  
Nociceptive Neurons ◽  
Neuropeptide Release ◽  
Selective Expression ◽  
Peripheral Sensory Neurons ◽  
Peripheral Sensory

Chronic pain is a leading health and socioeconomic problem and an unmet need exists for long-lasting analgesics. SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) are required for neuropeptide release and noxious signal transducer surface trafficking, thus, selective expression of the SNARE-cleaving light-chain protease of botulinum neurotoxin A (LCA) in peripheral sensory neurons could alleviate chronic pain. However, a safety concern to this approach is the lack of a sensory neuronal promoter to prevent the expression of LCA in the central nervous system. Towards this, we exploit the unique characteristics of Pirt (phosphoinositide-interacting regulator of TRP), which is expressed in peripheral nociceptive neurons. For the first time, we identified a Pirt promoter element and cloned it into a lentiviral vector driving transgene expression selectively in peripheral sensory neurons. Pirt promoter driven-LCA expression yielded rapid and concentration-dependent cleavage of SNAP-25 in cultured sensory neurons. Moreover, the transcripts of pain-related genes (TAC1, tachykinin precursor 1; CALCB, calcitonin gene-related peptide 2; HTR3A, 5-hydroxytryptamine receptor 3A; NPY2R, neuropeptide Y receptor Y2; GPR52, G protein-coupled receptor 52; SCN9A, sodium voltage-gated channel alpha subunit 9; TRPV1 and TRPA1, transient receptor potential cation channel subfamily V member 1 and subfamily A member 1) in pro-inflammatory cytokines stimulated sensory neurons were downregulated by viral mediated expression of LCA. Furthermore, viral expression of LCA yielded long-lasting inhibition of pain mediator release. Thus, we show that the engineered Pirt-LCA virus may provide a novel means for long lasting pain relief.

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