Studies on isolated smooth muscle cells. III. Calcium contraction of isolated cells from Vas deferens of guinea pig.

We examined changes in [3H]QNB binding and cell length induced by muscarinic ligands in a suspension of single smooth muscle cells isolated from the canine stomach. Cells contracted following a brief (30 s) exposure to picomolar concentrations of muscarinic agonists and yielded ED50 values of 1.0 +/- 0.7 pM for oxotremorine, 12.5 +/- 1.8 pM for carbachol, and 16.0 +/- 2.9 pM for metacholine. Contraction was inhibited by atropine with a pA2 value of 10.2 +/- 1.1. The binding of [3H]QNB was rapid and reversible and was stereospecific and pharmacologically appropriate. Specific binding of [3H]QNB was saturable and bound with high affinity (KD 1.04 +/- 0.23 nM) to a single class of sites, of which there were approximately 200,000/cell. In competition experiments antagonist binding was generally homogeneous, whereas that of agonists was heterogeneous and subpopulations of binding sites with different affinities for agonists were identified. The Ki value of 8.1 +/- 1.1 nM for inhibition of QNB binding by atropine was greater than the pA2 of 10.2 +/- 1.1 derived from contraction studies. Furthermore, whereas picomolar concentrations of agonists induced cell contraction, substantially higher concentrations (10 nM to 10 mM) were required to inhibit [3H]QNB binding to the isolated cells.

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Depolarization-mediated intracellular calcium transients in isolated smooth muscle cells of guinea-pig urinary bladder.

The Journal of Physiology ◽

10.1113/jphysiol.1991.sp018505 ◽

1991 ◽

Vol 435 (1) ◽

pp. 187-205 ◽

Cited By ~ 66

Author(s):

Y a Ganitkevich V ◽

G Isenberg

Keyword(s):

Smooth Muscle ◽

Urinary Bladder ◽

Guinea Pig ◽

Smooth Muscle Cells ◽

Intracellular Calcium ◽

Muscle Cells ◽

Calcium Transients ◽

Isolated Smooth Muscle Cells

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Effects of nicorandil on isolated smooth muscle cells from guinea-pig taenia caeci

Comparative Biochemistry and Physiology Part C Comparative Pharmacology ◽

10.1016/0742-8413(88)90143-0 ◽

1988 ◽

Vol 89 (1) ◽

pp. 45-52

Author(s):

Yasushi Ito ◽

Kazuo Obara

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Smooth Muscle Cells ◽

Muscle Cells ◽

Isolated Smooth Muscle Cells

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The Effect of Intracellular Current Pulses in Smooth Muscle Cells of the Guinea Pig Vas Deferens at Rest and during Transmission

The Journal of General Physiology ◽

10.1085/jgp.50.10.2459 ◽

1967 ◽

Vol 50 (10) ◽

pp. 2459-2475 ◽

Cited By ~ 36

Author(s):

M. R. Bennett

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Action Potential ◽

Smooth Muscle Cells ◽

Vas Deferens ◽

Electrical Coupling ◽

Muscle Cells ◽

Active Response ◽

Current Pulses ◽

Passive Response

The effect of intracellular current pulses on the membrane of smooth muscle cells of the guinea pig vas deferens at rest and during transmission was studied. Two main response types were identified: active response cells, in which a spike was initiated in response to depolarizing currents of sufficient strength and duration; passive response cells, in which depolarizing currents gave only electrotonic potential changes. These cells were three times more numerous than the active response cells. During the crest of the active response the input resistance fell by about 25% of the resting value. Comparison of the active response with the action potential due to stimulating the hypogastric nerve showed that the former was smaller in amplitude and had a slower rate of rise and higher threshold. Electrical coupling occurred between the smooth muscle cells during the propagation of the action potential. Depolarizing current pulses had no effect on the amplitude of the excitatory junction potential (E.J.P.) in passive response cells, but in general did decrease its amplitude in active response cells. These results are discussed with respect to the mechanism of autonomic neuroeffector transmission.

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