Altered beta-adrenergic and muscarinic response of CFTR Cl- current in dialyzed cardiac myocytes
| Autor: | Robert D. Harvey, S. I. Zakharov |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Male
medicine.medical_specialty Patch-Clamp Techniques Physiology Guinea Pigs Cystic Fibrosis Transmembrane Conductance Regulator Stimulation Chloride Channels Physiology (medical) Internal medicine Muscarine Muscarinic acetylcholine receptor Receptors Adrenergic beta medicine Myocyte Animals Patch clamp Ion transporter biology Chemistry Myocardium Electric Conductivity Isoproterenol Membrane Proteins Heart Cystic fibrosis transmembrane conductance regulator Acetylcholine Electrophysiology Endocrinology biology.protein Female Cardiology and Cardiovascular Medicine Dialysis medicine.drug |
| Zdroj: | The American journal of physiology. 268(5 Pt 2) |
| ISSN: | 0002-9513 |
| Popis: | Autonomic regulation of the cardiac cystic fibrosis transmembrane conductance regulator (CFTR) Cl- current was studied in isolated guinea pig ventricular myocytes using various configurations of the whole cell patch-clamp technique. When currents were recorded using the conventional patch-clamp technique, it was possible to continue to activate the Cl- current on repeated exposure to isoproterenol (Iso) for up to 60 min after initiating dialysis. However, there was significant rundown of the magnitude of the Cl- current response to the maximally stimulating concentrations of Iso. In addition, the concentration of Iso that produced half-maximal activation of the Cl- current (K1/2) increased with time. Conversely, the K1/2 for acetylcholine inhibition of the Iso-activated current decreased with time. When currents were recorded using the perforated patch-clamp technique, the sensitivity to both beta-adrenergic- and muscarinic-receptor stimulation was stable. Immediately after initiation of dialysis with the conventional patch-clamp technique, the sensitivity to Iso was nearly identical to that determined using the perforated patch-clamp technique. However, the initial sensitivity to muscarinic-receptor activation was significantly greater. These results indicate that cell dialysis associated with conventional patch-clamp techniques not only results in a time-dependent rundown of current amplitude, but it also significantly alters the concentration dependence of beta-adrenergic and muscarinic-receptor regulation of ion channel function. |
| Databáze: | OpenAIRE |
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