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

The effects of a potent phosphatase inhibitor, calyculin A (CL-A), on inward currents in guinea pig taenia coli smooth muscle cells were examined. CL-A increased the inward current, and this effect of CL-A was inhibited by a protein kinase C inhibitor, H-7, and by nifedipine. Phorbol 12,13-dibutyrate, an activator of protein kinase C, also increased the inward current and this effect was antagonized by H-7. These results suggest that in guinea pig taenia coli smooth muscle cells CL-A may facilitate the opening of thel-type Ca²⁺ channels through the protein kinase C-dependent phosphorylation system.     

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

The effects of a potent phosphatase inhibitor, calyculin A (CL-A), on inward currents in guinea pig taenia coli smooth muscle cells were examined. CL-A increased the inward current, and this effect of CL-A was inhibited by a protein kinase C inhibitor, H-7, and by nifedipine. Phorbol 12,13-dibutyrate, an activator of protein kinase C, also increased the inward current and this effect was antagonized by H-7. These results suggest that in guinea pig taenia coli smooth muscle cells CL-A may facilitate the opening of the L-type Ca2+ channels through the protein kinase C-dependent phosphorylation system.     

Antinicotinic properties of papaverine in guinea-pig taenia coli

Zusammenfassung Mit Hilfe der Saccharosetrennwand-Methode wird nachgewiesen, dass Papaverin antinikotinisch an der glatten Muskulatur (Taenia coli) des Meerschweinchens wirkt.     

Papaverine blockade of the calcium action in depolarized taenia coli of the guinea-pig

Zusammenfassung Es wird die muskellähmende Wirkung von Papaverin auf die depolarisierte Taenia coli durch die Blockade des Kalziumionenstromes durch die Zellmembran erklärt.     

Calcium and the contractile response to prostaglandin in the smooth muscle of guinea-pig stomach

Summary In the longitudinal smooth muscle of guinea-pig stomach, verapamil (10^–5 M) which showed marked suppression of high K-induced contractures, did not suppress the contractile response to PGE₁ (1.5×10^–9 to 10^–6 M) markedly. These results suggest that the contractile mechanism of PGE₁ in guinea-pig stomach may mainly depend on a release of bound Ca in the cell and partly depend on a Ca influx from the extracellular origin.     

Pathways for excitatory and inhibitory innervation to the guinea-pig tracheal smooth muscle

Summary The trachea receives excitatory cholinergic innervation from the vagus nerve and the stellate ganglion. Inhibitory adrenergic fibres have the same sources. Those in the vagus nerve probably derive from high vagosympathetic anastomoses. Nonadrenergic inhibitory fibres have a preganglionic vagal supply.This study has been supported by grants from Magnus Bergvall Memorial Found and Harald and Greta Jeansson Foundation.     

The effect of urethane on histamine-induced contraction of guinea-pig tracheal smooth muscle

Summary Urethane possesses a direct depressant action on histamine-induced contractions of guinea-pig tracheal smooth muscle both in vivo and in vitro.     

Pathways for excitatory and inhibitory innervation to the guinea-pig tracheal smooth muscle.

The trachea receives excitatory cholinergic innervation from the vagus nerve and the stellate ganglion. Inhibitory adrenergic fibres have the same sources. Those in the vagus nerve probably derive from high vagosympathetic anastomoses. Nonadrenergic inhibitory fibres have a preganglionic vagal supply.     

Electrical slow waves in oviductal smooth muscle of the guinea-pig,mouse and the immature baboon

Summary Oviducts of the guinea-pig, mouse and immature baboon show prominent electrical slow waves. In the guinea-pig oviduct they are 40–50 mV in amplitude and have a duration of 1.5 sec in the isthmus. Slow waves in these tissues propagate at a speed of 1–13 mm/sec.Decreased 6th December 1977.Supported by NIH-09339-02 and Rockefeller Foundation. A. T. was a Rockefeller Foundation Fellow. Correspondence to B. J. Hodgson, Dept. Obstetrics and Gynecology, UTHSCSA, San Antonio, Texas 78284.     

Colchicine-induced appearance (proliferation) of smooth sarcoplasmic reticulum in arterial smooth muscle cells

Colchicine treatment resulted in the appearance and proliferation of smooth sarcoplasmic reticulum in some smooth muscle cells of the aortic and pulmonary trunk walls in the rabbit. The significance of cytoplasmic microtubules and/or membrane-bound tubulin for the morphogenesis, functioning and control of smooth endoplasmic reticulum in different kinds of cells is discussed.     

Colchicine-induced appearance (proliferation) of smooth sarcoplasmic reticulum in arterial smooth muscle cells

Summary Colchicine treatment resulted in the appearance and proliferation of smooth sarcoplasmic reticulum in some smooth muscle cells of the aortic and pulmonary trunk walls in the rabbit. The significance of cytoplasmic microtubules and/or membrane-bound tubulin for the morphogenesis, functioning and control of smooth endoplasmic reticulum in different kinds of cells is discussed.     

Shortening velocity of single muscle cells isolated from a molluscan smooth muscle

Summary The maximal unloaded shortening velocity (V_max) of smooth muscle cells isolated from the pedal retractor muscle ofMytilus was more than twice as large as that of the whole muscle, suggesting the presence of extracellular components which resist the contraction of the whole muscle. The V_max of the isolated cells was almost constant at cell lengths ranging between 0.5 and 0.831₀ (1₀, optimal length for tension generation) indicating that the intracellular resistance to contraction is negligible within this range of lengths.     

Ionically induced volume changes of the smooth muscle of the guinea-pigTaenia coli

Zusammenfassung Analyse des unterschiedlichen Verhaltens eines glatten Muskels in Locke- und Krebs-Lösung.     

Desensitization to histamine in the absence of external Ca++ in the guinea-pig taenia caecum

Short-term desensitization of the contractile response of the guinea-pig taenia caecum to histamine was tested in the absence of Ca++. Desensitization was monitored both by the fall of histamine response and by the decrease of irreversible blockade by phenoxybenzamine. In Ca++-free solution with 0.2 mM EGTA, desensitization occurred as in normal physiological solution containing Ca++.