title: Effects of anthopleurin-Q on the intracellular free Ca2+ concentration in cultured rat cortical neurons.
abstract: The present study was designed to investigate the mechanism underlying the intracellular free Ca(2+) concentration ([Ca(2+)]i) modulated by Anthopleurin-Q (AP-Q), a sea anemone toxin, using whole-cell patch clamp and fluorescence digital imaging techniques. Results indicated that the overall Ca(2+) concentration could be augmented in presence of AP-Q. The increase of [Ca(2+)]i induced by AP-Q was eliminated in Na(+)-free solution, Ca(2+)-free solution or in presence of TTX. However, the Ca(2+) increase induced by AP-Q could not be influenced by cyclopiazonic acid (CPA), a specific inhibitor of the endoplasmic reticulum Ca(2+)-ATPase pump. We furthermore demonstrated that voltage-gated calcium channels (VGCCs) blocker verapamil, or inhibitor of the reverse operation Na(+)-Ca(2+) exchanger NiCl2 attenuated AP-Q-induced [Ca(2+)]i elevation. Furthermore, the inactivation process of Na(+) current (I Na ) was significantly delayed with slightly change of its amplitude by AP-Q. These findings demonstrated that neuron voltage-gated Na(+) channels are also targets of AP-Q. Overall, the present results suggested that AP-Q induced calcium influx via Na(+)-dependent activation of voltage-gated sodium channels (VGSCs), VGCCs and reverse operation of the Na(+)/Ca(2+)exchanger.
authors.affiliation: Department of Pharmacy, The Central Hospital of Wuhan, Tongji Medical -College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: F
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Urinary Surgery, The Central Hospital of Wuhan, Tongji -Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: D
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Pharmacy, The Central Hospital of Wuhan, Tongji Medical -College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Pharmacy, The Central Hospital of Wuhan, Tongji Medical -College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: A
authors.initials: A
authors.lastname: Deng
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000494:pharmacology*; D061251:Primary Cell Culture; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D015222:Sodium Channels; C477842:anthopleurin-Q; D012964:Sodium; D002118:Calcium