Effects of cooling on histamine-induced contractions of human umbilical artery: the role of ion channels.
The effects of cooling (to 28 degrees C) on histamine (10(-9) - 3 x 10(-4) M)-induced contractions and the role of calcium (Ca(2+)), potassium (K(Ca) (2+)) and sodium (Na(+)) channel blockers in the cooling-induced responses were investigated in the endothelium-denuded human umbilical artery. Concentration-response curves to histamine were isometrically recorded at 37 and 28 degrees C (control). The same procedure was repeated at 28 degrees C in the presence of tetraethylammonium (TEA, 10(-3) M), pilsicainide (10(-6) M), ouabain (10(-6) M), caffeine (3 x 10(-4) M), verapamil (10(-6) M) and also in Ca(2+)-free medium with ethylene glycol bis-(beta-aminoethyl ether) N,N,N(1),N(1)-tetraacetic acid (EGTA). During cooling, the sensitivity, but not the maximal response, was significantly higher than 37 degrees C. Cooling to 28 degrees C after treatment with verapamil or pilsicainide decreased the sensitivity, whereas treatment with TEA and ouabain significantly increased sensitivity. Treatment with caffeine did not modify the effect of cooling. Furthermore, cooling to 28 degrees C after incubation in Ca(2+)-free solution with EGTA decreased the sensitivity to histamine. The results of this study suggest the role of Ca(2+), K(Ca) (2+) and Na(+)-ion channels in the cooling-induced changes of human umbilical arteries treated with histamine.
Atalik
K E
KE
Department of Pharmacology, Faculty of Meram Medicine, University of Selcuk, Konya, Turkey. esraatalik@hotmail.com
Kiliç
M
M
Nurullahoğlu
Z U
ZU
Doğan
N
N
D002121:Calcium Channel Blockers / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006632:Histamine / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D007036:Hypothermia, Induced; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D014469:Umbilical Arteries / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D002121:Calcium Channel Blockers; D007473:Ion Channels; D026902:Potassium Channel Blockers; D026941:Sodium Channel Blockers; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D006632:Histamine; D012964:Sodium