Intracellular pH Modulates Taste Receptor Cell Volume and the Phasic Part of the Chorda Tympani Response to Acids
| Autor: | Anna K. Vinnikova, Shobha Mummalaneni, Hampton Pasley, Vijay Lyall, Gerard L. Heck, Tam-Hao T. Phan, John A. DeSimone |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
medicine.medical_specialty
Patch-Clamp Techniques Physiology Phalloidin Intracellular pH Voltage clamp Receptors Cell Surface macromolecular substances In Vitro Techniques Article Membrane Potentials Tonic (physiology) Rats Sprague-Dawley 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine stomatognathic system Internal medicine medicine Animals Mannitol Patch clamp Egtazic Acid Cytochalasin B Cytoskeleton Cell Size 030304 developmental biology 0303 health sciences Osmolar Concentration Carbon Dioxide Hydrogen-Ion Concentration Fluoresceins Taste Buds Actin cytoskeleton Actins Flufenamic Acid Rats Flufenamic acid Endocrinology chemistry Biophysics Female Chorda Tympani Nerve Hydrochloric Acid 030217 neurology & neurosurgery medicine.drug |
| Zdroj: | The Journal of General Physiology |
| ISSN: | 1540-7748 0022-1295 |
| Popis: | The relationship between cell volume and the neural response to acidic stimuli was investigated by simultaneous measurements of intracellular pH (pHi) and cell volume in polarized fungiform taste receptor cells (TRCs) using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) in vitro and by rat chorda tympani (CT) nerve recordings in vivo. CT responses to HCl and CO2 were recorded in the presence of 1 M mannitol and specific probes for filamentous (F) actin (phalloidin) and monomeric (G) actin (cytochalasin B) under lingual voltage clamp. Acidic stimuli reversibly decrease TRC pHi and cell volume. In isolated TRCs F-actin and G-actin were labeled with rhodamine phalloidin and bovine pancreatic deoxyribonuclease-1 conjugated with Alexa Fluor 488, respectively. A decrease in pHi shifted the equilibrium from F-actin to G-actin. Treatment with phalloidin or cytochalasin B attenuated the magnitude of the pHi-induced decrease in TRC volume. The phasic part of the CT response to HCl or CO2 was significantly decreased by preshrinking TRCs with hypertonic mannitol and lingual application of 1.2 mM phalloidin or 20 μM cytochalasin B with no effect on the tonic part of the CT response. In TRCs first treated with cytochalasin B, the decrease in the magnitude of the phasic response to acidic stimuli was reversed by phalloidin treatment. The pHi-induced decrease in TRC volume induced a flufenamic acid–sensitive nonselective basolateral cation conductance. Channel activity was enhanced at positive lingual clamp voltages. Lingual application of flufenamic acid decreased the magnitude of the phasic part of the CT response to HCl and CO2. Flufenamic acid and hypertonic mannitol were additive in inhibiting the phasic response. We conclude that a decrease in pHi induces TRC shrinkage through its effect on the actin cytoskeleton and activates a flufenamic acid–sensitive basolateral cation conductance that is involved in eliciting the phasic part of the CT response to acidic stimuli. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|