Basic properties of an inositol 1,4,5-trisphosphate-gated channel in carp olfactory cilia

Autor:	H, Cadiou, I, Sienaert, S, Vanlingen, J B, Parys, G, Molle, H, Duclohier
Rok vydání:	2000
Předmět:	Mammals Carps Patch-Clamp Techniques Heparin Myocardium Blotting Western Lipid Bilayers Anticoagulants Receptors Cytoplasmic and Nuclear Inositol 1 4 5-Trisphosphate Ruthenium Red Membrane Potentials Olfactory Mucosa Species Specificity Barium Cerebellum Microsomes Animals Inositol 1 4 5-Trisphosphate Receptors Calcium Indicators and Reagents Calcium Channels Cilia Ion Channel Gating
Zdroj:	The European journal of neuroscience. 12(8)
ISSN:	0953-816X
Popis:	In addition to the activation of cAMP-dependent pathways, odorant binding to its receptor can lead to inositol 1,4,5-trisphosphate (InsP3) production that may induce the opening of plasma membrane channels. We therefore investigated the presence and nature of such channels in carp olfactory cilia. Functional analysis was performed by reconstitution of the olfactory cilia in planar lipid bilayers (tip-dip method). In the presence of InsP3 (10 microM) and Ca2+ (100 nM), a current of 1.6 +/- 0.1 pA (mean +/- SEM, n = 4) was measured, using Ba2+ as charge carrier. The I/V curve displayed a slope conductance of 45 +/- 5 pS and a reversal potential of -29 mV indicating a higher selectivity for divalent cations. This current was characterized by two mean open times (3.0 +/- 0.4 ms and 42.0 +/- 2.6 ms, n = 4) and was strongly inhibited by ruthenium red (30 microM) or heparin (10 microg/mL). Importantly, the channel activity was closely dependent on the Ca2+ concentration, with the highest open probability (Po) at 100 nM Ca2+ (Po = 0.50 +/- 0.02, n = 4). Po is lower at both higher and lower Ca2+ concentrations. A structural identification of the channel was attempted by using a large panel of antibodies, raised against several InsP3 receptor (InsP3R)/Ca2+ release channel isoforms. The type 1 InsP3R was detected in carp cerebellum and whole brain, while a lower molecular mass InsP3R, which may correspond to type 2 or 3, was detected in heart, whole brain and the soma of the olfactory neurons. None of the antibodies, however, cross-reacted with olfactory cilia. Taken together, these results indicate that in carp olfactory cilia an InsP3-dependent channel is present, distinct from the classical InsP3Rs localized on intracellular membranes.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=pmid________::7d07cc4c8cf1ee778b49884f35523c5f https://pubmed.ncbi.nlm.nih.gov/10971622 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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