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Effects of epinephrine on electrical properties of Madin-Darby canine kidney cells.
- Source :
- Pflügers Archiv: European Journal of Physiology; 1986, Vol. 406 Issue 4, p367-371, 5p
- Publication Year :
- 1986
-
Abstract
- The present study has been performed, to test for the influence of epinephrine on the potential difference across the cell membrane (PD) of Madin-Darby canine kidney (MDCK) cells. Under control conditions, mimicking the in vivo situation, PD averages −53.3±0.9 mV ( n=37). Increasing extracellular potassium concentration from 5.4 to 10 and 20 mmol/l depolarizes the cell membrane by +4.3±0.4 mV ( n=5) and +15.8±1.2 mV ( n=5), respectively. The application of 1 μmol/l epinephrine leads to sustained hyperpolarization of the cell membrane to −71.5±0.7 mV ( n=37). In the presence of epinephrine, increasing extracellular potassium concentration from 5.4 to 20 mmol/l depolarizes the cell membrane by +30.6 ±0.2 mV ( n=5); 1 mmol/l barium depolarizes the cell membrane by +14.8±0.7 mV ( n=20) and abolishes the effect of step increases of extracellular potassium concentration from 5.4 to 10 mmol/l. In the presence of barium, epinephrine leads to a transient hyperpolarization by −31.2 ±1.2 mV ( n=18). During this transient hyperpolarization, the cell membrane is sensitive to extracellular potassium concentration despite the continued presence of barium; 10 μmol/l verapamil depolarizes the cell membrane to −41.0±2.6 mV ( n=11). In the presence of verapamil, the hyperpolarizing effect of epinephrine is only transient; 10 μmol/l phentolamine depolarizes the cell membrane by +3.0±0.6 mV ( n=8). In the presence of phentolamine, the effect of epinephrine is virtually abolished (+0.4±0.6 mV, n=8); 1 μmol/l isoproterenol depolarizes the cell membrane by +2.8±0.8 mV ( n=8). In the norminal absence of extracellular calcium, epinephrine leads to a transient hyperpolarization, which can only be elicited once. In conclusion, cpinephrine hyperpolarizes MDCK cells by increasing the apparent potassium conductance. This effect is transmitted by α-receptors and may be mediated by increases of intracellular calcium activity. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00316768
- Volume :
- 406
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Pflügers Archiv: European Journal of Physiology
- Publication Type :
- Academic Journal
- Accession number :
- 73149367
- Full Text :
- https://doi.org/10.1007/BF00590938