Calyculin a increases voltage-dependent inward current in, smooth muscle cells isolated from guinea pig taenia coli

1991 ◽  
Vol 47 (9) ◽  
pp. 939-941 ◽  
Author(s):  
T. Usuki ◽  
K. Obara ◽  
T. Someya ◽  
H. Ozaki ◽  
H. Karaki ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Calyculin A ◽  
Taenia Coli ◽  
Inward Current ◽  
Voltage Dependent

scholarly journals Inward current in single smooth muscle cells of the guinea pig taenia coli.

1989 ◽  
Vol 93 (3) ◽  
pp. 521-550 ◽  
Author(s):  
Y Yamamoto ◽  
S L Hu ◽  
C Y Kao
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Time Course ◽  
Reversal Potential ◽  
Muscle Cells ◽  
Taenia Coli ◽  
Average Cell ◽  
Time Constants ◽  
Inward Current

Using the tight-seal voltage-clamp method, the ionic currents in the enzymatically dispersed single smooth muscle cells of the guinea pig taenia coli have been studied. In a physiological medium containing 3 mM Ca2+, the cells are gently tapering spindles, averaging 201 (length) x 8 microns (largest diameter in center of cell), with a volume of 5 pl. The average cell capacitance is 50 pF, and the specific membrane capacitance 1.15 microF/cm2. The input impedance of the resting cell is 1-2 G omega. Spatially uniform voltage-control prevails after the first 400 microseconds. There is much overlap of the inward and outward currents, but the inward current can be isolated by applying Cs+ internally to block all potassium currents. The inward current is carried by Ca2+. Activation begins at approximately -30 mV, maximum ICa occurs at +10-+20 mV, and the reversal potential is approximately +75 mV. The Ca2+ channel is permeable to Sr2+ and Ba2+, and to Cs+ moving outwards, but not to Na+ moving inwards. Activation and deactivation are very rapid at approximately 33 degrees C, with time-constants of less than 1 ms. Inactivation has a complex time course, resolvable into three exponential components, with average time constants (at 0 mV) of 7, 45, and 400 ms, which are affected differently by voltage. Steady-state inactivation is half-maximal at -30 mV for all components combined, but -36 mV for the fast component and -26 and -23 mV for the other two components. The presence of multiple forms of Ca2+ channel is inferred from the inactivation characteristics, not from activation properties. Recovery of the fast channel occurs with a time-constant of 72 ms (at +10 mV). Ca2+ influx during an action potential can transfer approximately 9 pC of charge, which could elevate intracellular Ca2+ concentration adequately for various physiological functions.

The effect of apamin on the smooth muscle cells of the guinea-pig taenia coli

1979 ◽  
Vol 58 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Ad J.J. Maas ◽  
Adriaan Den Hertog
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Taenia Coli

Voltage-dependent calcium channel current in isolated gallbladder smooth muscle cells of guinea pig

1993 ◽  
Vol 264 (6) ◽  
pp. G1066-G1076 ◽  
Author(s):  
T. Shimada
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Time Course ◽  
Reversal Potential ◽  
High Sensitivity ◽  
Muscle Cells ◽  
Patch Clamp Technique ◽  
Decay Component ◽  
Voltage Dependent

The voltage-dependent Ca2+ current was studied in enzymatically dispersed guinea pig gallbladder smooth muscle cells using the whole cell patch-clamp technique. Depolarizing voltage (V) steps induced an inward current (I) that was carried by Ca2+. The threshold potential was -40 to -30 mV, the maximal current was observed at +10 to +20 mV, and the reversal potential was around +80 mV. I-V curves obtained with holding potentials of -80 and -40 mV were not significantly different. This current had a high sensitivity to dihydropyridine drugs, and the Ba2+ or Sr2+ current was larger than the Ca2+ current. Activation was accelerated by increasing the membrane potential. In general, the time course of decay was well fitted by the sum of two exponentials, but consideration of a third (ultra-slow) decay component was also necessary when the current generated by a 2-s command pulse was analyzed. Superimposition of activation and inactivation curves showed the presence of a significant window current. Carbachol suppressed the Ca2+ current only when the pipette contained a low concentration of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. These results show that the L-type Ca2+ current is dominant in gallbladder smooth muscle cells and may contribute to excitation-contraction coupling.

scholarly journals Effect of DFP on loading of fura-2/AM into single smooth muscle cells prepared from guinea pig taenia coli

1987 ◽  
Vol 43 ◽  
pp. 240
Author(s):  
Hideto Oyamada ◽  
Ikuo Maruyama ◽  
Tomohiko Hasegawa ◽  
Kazuko Otsuka ◽  
Kazutaka Momose
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Taenia Coli ◽  
Fura 2
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