title: Ceramide inhibits Kv currents and contributes to TP-receptor-induced vasoconstriction in rat and human pulmonary arteries.
abstract: Neutral sphingomyelinase (nSMase)-derived ceramide has been proposed as a mediator of hypoxic pulmonary vasoconstriction (HPV), a specific response of the pulmonary circulation. Voltage-gated K(+) (K(v)) channels are modulated by numerous vasoactive factors, including hypoxia, and their inhibition has been involved in HPV. Herein, we have analyzed the effects of ceramide on K(v) currents and contractility in rat pulmonary arteries (PA) and in mesenteric arteries (MA). The ceramide analog C6-ceramide inhibited K(v) currents in PA smooth muscle cells (PASMC). Similar effects were obtained after the addition of bacterial sphingomyelinase (SMase), indicating a role for endogenous ceramide in K(v) channel regulation. K(v) current was reduced by stromatoxin and diphenylphosphine oxide-1 (DPO-1), selective inhibitors of K(v)2.1 and K(v)1.5 channels, respectively. The inhibitory effect of ceramide was still present in the presence of stromatoxin or DPO-1, suggesting that this sphingolipid inhibited both components of the native K(v) current. Accordingly, ceramide inhibited K(v)1.5 and K(v)2.1 channels expressed in Ltk(-) cells. Ceramide-induced effects were reduced in human embryonic kidney 293 cells expressing K(v)1.5 channels but not the regulatory subunit K(v)β2.1. The nSMase inhibitor GW4869 reduced the thromboxane-endoperoxide receptor agonist U46619-induced, but not endothelin-1-induced pulmonary vasoconstriction that was partly restored after addition of exogenous ceramide. The PKC-ζ pseudosubstrate inhibitor (PKCζ-PI) inhibited the K(v) inhibitory and contractile effects of ceramide. In MA ceramide had no effect on K(v) currents and GW4869 did not affect U46619-induced contraction. The effects of SMase were also observed in human PA. These results suggest that ceramide represents a crucial signaling mediator in the pulmonary vasculature.
authors.affiliation: Department of Pharmacology, School of Medicine, Universidad Complutense Madrid, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Moral-Sanz
authors.forename: Teresa
authors.initials: T
authors.lastname: Gonzalez
authors.forename: Carmen
authors.initials: C
authors.lastname: Menendez
authors.forename: Miren
authors.initials: M
authors.lastname: David
authors.forename: Laura
authors.initials: L
authors.lastname: Moreno
authors.forename: Alvaro
authors.initials: A
authors.lastname: Macias
authors.forename: Julio
authors.initials: J
authors.lastname: Cortijo
authors.forename: Carmen
authors.initials: C
authors.lastname: Valenzuela
authors.forename: Francisco
authors.initials: F
authors.lastname: Perez-Vizcaino
authors.forename: Angel
authors.initials: A
authors.lastname: Cogolludo
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D001597:Benzylidene Compounds / Q000494:pharmacology; D002518:Ceramides / Q000378:metabolism / Q000494:pharmacology*; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D008564:Membrane Potentials; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000494:pharmacology; D010720:Phosphines / Q000494:pharmacology; D024642:Potassium Channels, Voltage-Gated / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011651:Pulmonary Artery / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D017482:Receptors, Thromboxane / Q000378:metabolism; D015398:Signal Transduction; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism / Q000494:pharmacology; D013111:Spider Venoms / Q000494:pharmacology; D014655:Vascular Resistance; D014661:Vasoconstriction; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: C507236:(2-isopropyl-5-methylcyclohexyl) diphenylphosphine oxide; D000814:Aniline Compounds; D001597:Benzylidene Compounds; D002518:Ceramides; C468773:GW 4869; D010455:Peptides; D010720:Phosphines; D024642:Potassium Channels, Voltage-Gated; D017482:Receptors, Thromboxane; D013111:Spider Venoms; D014662:Vasoconstrictor Agents; C560803:stromatoxin protein, Stromatopelma calceata; C101954:N-caproylsphingosine; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D011493:Protein Kinase C; D013108:Sphingomyelin Phosphodiesterase