Ghrelin suppression of potassium currents in smooth muscle cells of human mesenteric artery.
Ghrelin is a 28-amino acid peptide hormone which modulates many physiological functions including cardiovascular homeostasis. Here we report some novel findings about the action of ghrelin on smooth muscle cells (SMC) freshly isolated from human mesenteric arteries. Ghrelin (10(-7) mol/l) significantly suppressed the iberiotoxin-blockable component of potassium currents (I(K)) and depolarized the cell membrane, while having no effect on Ca(2+) currents. Inhibition of inositol-trisphosphate (IP(3))-activated Ca(2+) release channels, depletion of sarcoplasmic reticulum (SR) Ca(2+) stores, blockade of phospholipase D (PLD) or protein kinase C (PKC) each abolished the effect of ghrelin on I(K), while the inhibition of phospholipase C (PLC) did not. These data imply that in human mesenteric artery SMC ghrelin suppresses I(K) via PLD, PKC and SR Ca(2+)-dependent signaling pathway.
Mladenov
M I
MI
Institute of Biology, Faculty of Natural Sciences and Mathematics, Sv. Kiril i Metodij University, Arhimedova 6, P.O.Box 162, Skopje, Republic of Macedonia. mitkoivan@yahoo.com
Hristov
K L
KL
Duridanova
D B
DB
D000368:Aged; D002118:Calcium / Q000378:metabolism; D005260:Female; D054439:Ghrelin; D006801:Humans; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D036361:Peptide Hormones / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism
D054439:Ghrelin; D036361:Peptide Hormones; D010455:Peptides; C064719:iberiotoxin; D011188:Potassium; D002118:Calcium