Calcium channels, potassium channels and membrane potential of smooth muscle cells of human allantochorial placental vessels
| Autor: | Andrée Guiet-Bara, Jean Leveteau, Bissiriou Ibrahim, Michel Bara |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Nitroprusside
Serotonin BK channel medicine.medical_specialty Potassium Channels Nifedipine Placenta Biophysics In Vitro Techniques Membrane Potentials SK channel Allantois Internal medicine Electrochemistry medicine Humans Nitric Oxide Donors Channel blocker Physical and Theoretical Chemistry Membrane potential biology Voltage-dependent calcium channel Chemistry Isoproterenol T-type calcium channel Muscle Smooth Cardiac action potential Chorion Adrenergic beta-Agonists Hyperpolarization (biology) Calcium Channel Blockers Acetylcholine Endocrinology cardiovascular system biology.protein Calcium Channels |
| Zdroj: | Bioelectrochemistry and Bioenergetics. 48:407-413 |
| ISSN: | 0302-4598 |
| Popis: | The membrane potential (Um), the main factor of the excitation–contraction coupling, of human allantochorial placental vascular smooth muscle cells (VSMCs) has been previously shown to depend on voltage-sensitive K+ channels. These channels were blocked by high external K+. To characterize other channels which regulated Um, various constrictor or/and vasodilators and channel blockers were used. Serotonin depolarized VSMCs, in normal medium, but induced a more marked depolarization in VSMCs predepolarized by high external K+. This depolarization was inhibited by nifedipine, a blocker of voltage-gated Ca2+ channels. Acetylcholine, sodium nitroprusside (without effect on Um in normal medium), hyperpolarized the predepolarized-high K+ medium VSMCs. This hyperpolarization was inhibited after addition of charybotoxin (a blocker of Ca2+-activated K+ channels) or/and glibenclamide (a blocker of ATP-sensitive K+ channels). A similar effect was obtained with isoproterenol. These results indicated that membrane potential of human placental allantochorial VSMCs was regulated by voltage-gated, Ca2+- and ATP-sensitive K+ channels and by voltage-dependent Ca2+ channels. |
| Databáze: | OpenAIRE |
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