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IP3 receptor in the hair cells of frog semicircular canal and its possible functional role.
Eur J Neurosci. 2006 Apr; 23(7):1775-83.EJ

Abstract

The presence and functional role of inositol trisphosphate receptors (IP3R) was investigated by electrophysiology and immunohistochemistry in hair cells from the frog semicircular canal. Intracellular recordings were performed from single fibres of the posterior canal in the isolated, intact frog labyrinth, at rest and during rotation, in the presence of IP3 receptor inhibitors and drugs known to produce Ca2+ release from the internal stores or to increase IP3 production. Hair cell immunolabelling for IP3 receptor was performed by standard procedures. The drug 2-aminoethoxydiphenyl borate (2APB), an IP3 receptor inhibitor, produced a marked decrease of mEPSP and spike frequency at low concentration (0.1 mm), without affecting mEPSP size or time course. At high concentration (1 mm), 2APB is reported to block the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase (SERCA pump) and increase [Ca2+]i; at the labyrinthine cytoneural junction, it greatly enhanced the resting and mechanically evoked sensory discharge frequency. The selective agonist of group I metabotropic glutamate receptors (RS)-3,5-dihydroxyphenylglycine (DHPG, 0.6 mm), produced a transient increase in resting mEPSP and spike frequency at the cytoneural junction, with no effects on mEPSP shape or amplitude. Pretreatment with cyclopiazonic acid (CPA, 0.1 mm), a SERCA pump inhibitor, prevented the facilitatory effect of both 2APB and DHPG, suggesting a link between Ca2+ release from intracellular stores and quantal emission. Consistently, diffuse immunoreactivity for IP3 receptors was observed in posterior canal hair cells. Our results indicate the presence and a possibly relevant functional role of IP3-sensitive stores in controlling [Ca2+]i and modulating the vestibular discharge.

Authors+Show Affiliations

Dipartimento di Biologia, Sezione di Fisiologia e Biofisica, Centro di Neuroscienze, Via L. Borsari, 46, I-44100, Ferrara, Italy. rsm@unife.itNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16623834

Citation

Rossi, Maria Lisa, et al. "IP3 Receptor in the Hair Cells of Frog Semicircular Canal and Its Possible Functional Role." The European Journal of Neuroscience, vol. 23, no. 7, 2006, pp. 1775-83.
Rossi ML, Prigioni I, Gioglio L, et al. IP3 receptor in the hair cells of frog semicircular canal and its possible functional role. Eur J Neurosci. 2006;23(7):1775-83.
Rossi, M. L., Prigioni, I., Gioglio, L., Rubbini, G., Russo, G., Martini, M., Farinelli, F., Rispoli, G., & Fesce, R. (2006). IP3 receptor in the hair cells of frog semicircular canal and its possible functional role. The European Journal of Neuroscience, 23(7), 1775-83.
Rossi ML, et al. IP3 Receptor in the Hair Cells of Frog Semicircular Canal and Its Possible Functional Role. Eur J Neurosci. 2006;23(7):1775-83. PubMed PMID: 16623834.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - IP3 receptor in the hair cells of frog semicircular canal and its possible functional role. AU - Rossi,Maria Lisa, AU - Prigioni,Ivo, AU - Gioglio,Luciana, AU - Rubbini,Gemma, AU - Russo,Giancarlo, AU - Martini,Marta, AU - Farinelli,Federica, AU - Rispoli,Giorgio, AU - Fesce,Riccardo, PY - 2006/4/21/pubmed PY - 2006/5/31/medline PY - 2006/4/21/entrez SP - 1775 EP - 83 JF - The European journal of neuroscience JO - Eur. J. Neurosci. VL - 23 IS - 7 N2 - The presence and functional role of inositol trisphosphate receptors (IP3R) was investigated by electrophysiology and immunohistochemistry in hair cells from the frog semicircular canal. Intracellular recordings were performed from single fibres of the posterior canal in the isolated, intact frog labyrinth, at rest and during rotation, in the presence of IP3 receptor inhibitors and drugs known to produce Ca2+ release from the internal stores or to increase IP3 production. Hair cell immunolabelling for IP3 receptor was performed by standard procedures. The drug 2-aminoethoxydiphenyl borate (2APB), an IP3 receptor inhibitor, produced a marked decrease of mEPSP and spike frequency at low concentration (0.1 mm), without affecting mEPSP size or time course. At high concentration (1 mm), 2APB is reported to block the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase (SERCA pump) and increase [Ca2+]i; at the labyrinthine cytoneural junction, it greatly enhanced the resting and mechanically evoked sensory discharge frequency. The selective agonist of group I metabotropic glutamate receptors (RS)-3,5-dihydroxyphenylglycine (DHPG, 0.6 mm), produced a transient increase in resting mEPSP and spike frequency at the cytoneural junction, with no effects on mEPSP shape or amplitude. Pretreatment with cyclopiazonic acid (CPA, 0.1 mm), a SERCA pump inhibitor, prevented the facilitatory effect of both 2APB and DHPG, suggesting a link between Ca2+ release from intracellular stores and quantal emission. Consistently, diffuse immunoreactivity for IP3 receptors was observed in posterior canal hair cells. Our results indicate the presence and a possibly relevant functional role of IP3-sensitive stores in controlling [Ca2+]i and modulating the vestibular discharge. SN - 0953-816X UR - https://www.unboundmedicine.com/medline/citation/16623834/IP3_receptor_in_the_hair_cells_of_frog_semicircular_canal_and_its_possible_functional_role_ L2 - https://doi.org/10.1111/j.1460-9568.2006.04708.x DB - PRIME DP - Unbound Medicine ER -