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  • 1
    Electronic Resource
    Electronic Resource
    Effects of bradykinin on electrical properties of Madin-Darby canine kidney epithelioid cells (1987)
    Springer
    Pflügers Archiv 408 (1987), S. 408-413 
    Details
    ISSN: 1432-2013
    Keywords: MDCK-cells ; Intracellular microelectrodes ; Cell membrane potential ; Potassium-conductance ; Barium ; Bradykinin ; Indomethacin ; Verapamil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In the present study we have investigated the influence of bradykinin on the potential difference across the cell membrane (PD) of Madin Darby Canine Kidney (MDCK)-cells. In the absence of bradykinin PD averages −52.6±0.9 mV (n=52). Increasing extracellular potassium concentration from 5.4 to 10 and 20 mmol/l depolarizes the cell membrane by +5.2±0.3 mV (n=8) and +14.9±1.0 mV (n=9), respectively. The application of 0.1 μmol/l bradykinin leads to a transient hyperpolarization of the cell membrane to −70.3±0.6 mV (n=30). During this transient hyperpolarization increasing extracellular potassium concentration from 5.4 to 10 and 20 mmol/l depolarizes the cell membrane by +10.4±0.7 mV (n=10) and +29.2±0.8 mV (n=8) respectively. Application of fragments of bradykinin (0.1 μmol/l) are without significant effect on the potential difference across the cell membrane. 1 mmol/l barium depolarizes the cell membrane by +15.8±1.2 mV (n=9) and abolishes the effect of step increase of extracellular potassium concentration from 5.4 to 10 mmol/l. In the presence of barium, bradykinin leads to a transient hyperpolarization by −24.7±1.3 mV (n=7). During this transient hyperpolarization, the cell membrane is sensitive to extracellular potassium concentration despite the continued presence of barium. In the nominal absence of extracellular calcium, bradykinin leads to a transient hyperpolarization, which can be elicited only once. The transient hyperpolarization is not affected by the presence of verapamil or indomethacin. In conclusion, bradykinin hyperpolarizes MDCK-cells by increasing the apparent potassium conductance. This effect is probably mediated by increase of intracellular calcium activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00581137
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  • 2
    Electronic Resource
    Electronic Resource
    Electrical properties of Madin-Darby-canine-kidney cells (1986)
    Springer
    Pflügers Archiv 407 (1986), S. 258-263 
    Details
    ISSN: 1432-2013
    Keywords: MDCK-cells ; Microelectrodes ; Cell membrane potential ; Potassium conductance ; Sodium ; Calcium ; Barium ; Amiloride ; A23187
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In incompletely confluent madin Darby canine kidney cells continuous measurements of the potential difference across the cell membrane (PD) were made with conventional microelectrodes during rapid changes of extracellular sodium and/or calcium concentration. During control conditions PD averages −50.6±0.7 mV. Reduction of extracellular sodium concentration from 131.8 to 17.8 mmol/l leads to a reversible hyperpolarization of the cell membrane to −65.3±1.1 mV. This hyperpolarization is not significantly reduced by omission of glucose or presence of amiloride (1 mmol/l) in the perfusates. Instead, 1 mmol/l amiloride depolarizes the cell membrane by +5.2±0.4 mV. 1 mmol/l barium depolarizes the cell membrane to −31.3±1.1 mV. Step increases of extracellular potassium concentration from 5.4 to 10 and 20 mmol/l depolarize the cell membrane by +5.5±0.5 mV and +16.5±1.8 mV respectively. In the presence of barium, the depolarizing effect of increasing extracellular potassium concentration and of amiloride is almost abolished. Reduction of extracellular sodium concentration in the presence of barium, however, leads to a transient hyperpolarization of the cell membrane. During this transient hyperpolarization, increasing extracellular potassium concentration depolarizes the cell membrane despite the continued presence of barium. Omission of extracellular calcium (EDTA) depolarizes the cell membrane by +36.7±3.2 mV. In the absence of extracellular calcium, the hyperpolarizing effect of reduced extracellular sodium concentration is markedly reduced (−4.5±1.2 mV). 2 μmol/l A23187 in the presence of extracellular calcium hyperpolarizes the cell membrane to −72.5±0.6 mV. In conclusion, reduction of extracellular sodium concentration increases the potassium conductance of the cell membrane, possibly by increasing intracellular calcium activity via an influence on the sodium/calcium-exchange.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00585300
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of serotonin on electrical properties of Madin-Darby canine kidney cells (1988)
    Springer
    Pflügers Archiv 411 (1988), S. 394-400 
    Details
    ISSN: 1432-2013
    Keywords: MDCK-cells ; Intracellular microelectrodes ; Cell membrane potential ; Potassium-conductance ; 5-Hydroxytryptamine (5-HT) ; Barium ; Methysergide ; ICS 205-930 ; Ketanserin ; Phentolamine ; Extracellular calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present study has been performed to test for the influence of serotonin on the potential difference across the cell membrane (PD) of Madin-Darby canine kidney (MDCK)-cells. Under control conditions PD averages −48.6±0.6 mV (n=98). Increasing extracellular potassium concentration from 5.4 to 10 and 20 mmol/l depolarizes the cell membrane by +6.3±0.6 mV (n=6) and +14.1±1.0 mV (n=12), respectively. The cell membrane is transiently hyperpolarized to −67.8±0.8 mV (n=63) by 1 μmol/l serotonin. In the presence of serotonin, increasing extracellular potassium concentration from 5.4 to 20 mmol/l depolarizes the cell membrane by +26.4±1.0 mV (n=11). 1 mmol/l barium depolarizes the cell membrane by +15.7±1.3 mV (n=17) and abolishes the effect of step increases of extracellular potassium concentration from 5.4 to 10 mmol/l. In the presence of barium, serotonin leads to a transient hyperpolarization by −26.3±1.0 mV (n=16). During this transient hyperpolarization, the cell membrane is sensitive to extracellular potassium concentration despite the continued presence of barium. 10 μmol/l methysergide hyperpolarize the cell membrane by −7.2±2.0 mV (n=6). In the presence of 10μmol/l methysergide, the effect of serotonin is virtually abolished (+0.4±0.9 mV,n=6). 1 μmol/l ketanserin, a 5-HT2 receptor blocking agent, ICS 205-930, a 5-HT3 receptor blocking agent, and phentolamine, an unspecific α-receptor blocking agent, do not significantly modify the effect of serotonin. In the nominal absence of extracellular calcium, the effect of serotonin is markedly reduced. In conclusion, serotonin hyperpolarizes MDCK-cells by increasing apparent potassium conductance. This effect is transmitted by 5-HT1 receptors and depends on extracellular calcium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587718
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    Paper (German National Licenses)
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