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Omega-conotoxin GVIA potently inhibits the currents mediated by P2X receptors in rat DRG neurons.
Brain Res Bull 2001; 54(5):507-12BR

Abstract

We examined effects of omega-conotoxin previously known as a selective blocker of N-type calcium channels, on the adenosine triphosphate (ATP)-induced currents in the rat dorsal root ganglion neurons. These neurons express at least two types of ionotropic purinoreceptors: P2X3 receptors that have very rapid desensitization kinetics and P2X2/X3 heterooligomeric receptor, which exhibits slow desensitization. We have found that omega-conotoxin GVIA potently inhibits the inward currents mediated by both receptor types. This effect was specific for the receptor subtypes: the IC(50) value for responses evoked by 10 microM ATP was 21.2 +/- 1.7 nM for the P2X3 receptor-mediated responses and 3.84 +/- 0.43 microM for slower responses mediated by P2X2/X3 heteropolymers. The efficacy of another type of omega-conotoxin, MVIIC, is much lower: at 10 microM the latter toxin inhibited the rapidly desensitizing response by 65% and the slowly desensitizing response by 18%. The effects of both toxins were reversible and independent on the membrane potential. Omega-Conotoxin GVIA shifted the dose dependence for the agonistic action of ATP on P2X3 receptors to higher concentrations without producing any effect on the kinetics of the response. It is suggested that omega-conotoxin allosterically modulates the receptor properties, rather than competes for the agonist binding site.

Authors+Show Affiliations

Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine.No 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

11397540

Citation

Lalo, U V., et al. "Omega-conotoxin GVIA Potently Inhibits the Currents Mediated By P2X Receptors in Rat DRG Neurons." Brain Research Bulletin, vol. 54, no. 5, 2001, pp. 507-12.
Lalo UV, Pankratov YV, Arndts D, et al. Omega-conotoxin GVIA potently inhibits the currents mediated by P2X receptors in rat DRG neurons. Brain Res Bull. 2001;54(5):507-12.
Lalo, U. V., Pankratov, Y. V., Arndts, D., & Krishtal, O. A. (2001). Omega-conotoxin GVIA potently inhibits the currents mediated by P2X receptors in rat DRG neurons. Brain Research Bulletin, 54(5), pp. 507-12.
Lalo UV, et al. Omega-conotoxin GVIA Potently Inhibits the Currents Mediated By P2X Receptors in Rat DRG Neurons. Brain Res Bull. 2001 Mar 15;54(5):507-12. PubMed PMID: 11397540.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Omega-conotoxin GVIA potently inhibits the currents mediated by P2X receptors in rat DRG neurons. AU - Lalo,U V, AU - Pankratov,Y V, AU - Arndts,D, AU - Krishtal,O A, PY - 2001/6/9/pubmed PY - 2001/7/28/medline PY - 2001/6/9/entrez SP - 507 EP - 12 JF - Brain research bulletin JO - Brain Res. Bull. VL - 54 IS - 5 N2 - We examined effects of omega-conotoxin previously known as a selective blocker of N-type calcium channels, on the adenosine triphosphate (ATP)-induced currents in the rat dorsal root ganglion neurons. These neurons express at least two types of ionotropic purinoreceptors: P2X3 receptors that have very rapid desensitization kinetics and P2X2/X3 heterooligomeric receptor, which exhibits slow desensitization. We have found that omega-conotoxin GVIA potently inhibits the inward currents mediated by both receptor types. This effect was specific for the receptor subtypes: the IC(50) value for responses evoked by 10 microM ATP was 21.2 +/- 1.7 nM for the P2X3 receptor-mediated responses and 3.84 +/- 0.43 microM for slower responses mediated by P2X2/X3 heteropolymers. The efficacy of another type of omega-conotoxin, MVIIC, is much lower: at 10 microM the latter toxin inhibited the rapidly desensitizing response by 65% and the slowly desensitizing response by 18%. The effects of both toxins were reversible and independent on the membrane potential. Omega-Conotoxin GVIA shifted the dose dependence for the agonistic action of ATP on P2X3 receptors to higher concentrations without producing any effect on the kinetics of the response. It is suggested that omega-conotoxin allosterically modulates the receptor properties, rather than competes for the agonist binding site. SN - 0361-9230 UR - https://www.unboundmedicine.com/medline/citation/11397540/Omega_conotoxin_GVIA_potently_inhibits_the_currents_mediated_by_P2X_receptors_in_rat_DRG_neurons_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0361-9230(01)00433-6 DB - PRIME DP - Unbound Medicine ER -