Effects of Cyproheptadine, Ketotifen and Sodium Nitroprusside on Mechanical Activity and Calcium Uptake in Guinea Pig Taenia coli in vitro

Respiration ◽  
1980 ◽  
Vol 39 (1) ◽  
pp. 44-46 ◽  
Author(s):  
D.A. Lowe ◽  
B.P. Richardson
Keyword(s):  
Guinea Pig ◽  
Sodium Nitroprusside ◽  
Calcium Uptake ◽  
Mechanical Activity ◽  
Taenia Coli

Endogenous prostaglandin in guinea pig taenia coli

1976 ◽  
Vol 230 (1) ◽  
pp. 149-157 ◽  
Author(s):  
T Yamaguchi ◽  
B Hitzig ◽  
RF Coburn
Keyword(s):  
Guinea Pig ◽  
Surface Membrane ◽  
Membrane Resistance ◽  
Threshold Concentration ◽  
Mechanical Activity ◽  
Taenia Coli ◽  
Endogenous Prostaglandin ◽  
Sucrose Gap ◽  
Spontaneous Action ◽  
Spontaneous Action Potentials

Prostaglandin (PGE) is synthesized in the guinea pig taenia coli. A low threshold concentration for an effect of exogenous PGE1 or PGE2 on spontaneous mechanical activity was demonstrated. The PG synthetase inhibitors aspirin, indomethacin, and 5,8,11,14-eicosatetraynoic acid, at concentrations that inhibited PGE efflux, had effects on spontaneous mechanical activity, membrane potential, membrane resistance, and evoked and spontaneous action potentials (single and double sucrose-gap methods) that were consistent with an action due to inhibition of membrane PGE concentration. The threshold concentration of indomethacin, which inhibited PGE efflux, was the same as the concentration that inhibited spontaneous mechanical activity. Pretreatment with ouabain (10(-6)-10(-5) g/ml) or elevated extracellular K+ (29 and 126 mM) made the guinea pig taenia coli entirely refractory to exogenous PGE1 or PGE2; the mechanical effects of the three prostaglandin synthetase inhibitors also were absent in the presence of elevated K+ or ouabain. The data are consistent with a hypothesis that, under conditions of our experiments, endogenous PGE has an effect on resting tension and spontaneous mechanical activity and on properties of the surface membrane of the guinea pig taenia coli.

NO donor sodium nitroprusside inhibits excitation-contraction coupling in guinea pig taenia coli

2000 ◽  
Vol 279 (6) ◽  
pp. G1235-G1241 ◽  
Author(s):  
Seong-Chun Kwon ◽  
Hiroshi Ozaki ◽  
Hideaki Karaki
Keyword(s):  
Guinea Pig ◽  
Sodium Nitroprusside ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Soluble Guanylate Cyclase ◽  
Myosin Light Chain Phosphorylation ◽  
Taenia Coli ◽  
Patch Clamp Technique ◽  
No Donor ◽  
Camp Content

In guinea pig taenia coli, the nitric oxide (NO) donor sodium nitroprusside (SNP, 1 μM) reduced the carbachol-stimulated increases in muscle force in parallel with a decrease in intracellular Ca2+ concentration ([Ca2+]i). A decrease in the myosin light chain phosphorylation was also observed that was closely correlated with the decrease in [Ca2+]i. With the patch-clamp technique, 10 μM SNP decreased the peak Ba2+current, and this effect was blocked by an inhibitor of soluble guanylate cyclase. Carbachol (10 μM) induced an inward current, and this effect was markedly inhibited by SNP. SNP markedly increased the depolarization-activated outward K+ currents, and this current was completely blocked by 0.3 μM iberiotoxin. SNP (1 μM) significantly increased cGMP content without changing cAMP content. Decreased Ca2+ sensitivity by SNP of contractile elements was not prominent in the permeabilized taenia, which was consistent with the [Ca2+]i-force relationship in the intact tissue. These results suggest that SNP inhibits myosin light chain phosphorylation and smooth muscle contraction stimulated by carbachol, mainly by decreasing [Ca2+]i, which resulted from the combination of the inhibition of voltage-dependent Ca2+ channels, the inhibition of nonselective cation currents, and the activation of Ca2+-activated K+ currents.

Effects of phospholipase C on the electrical and mechanical activity of guinea pig taenia coli

1977 ◽  
Vol 9 (3) ◽  
pp. 251-258
Author(s):  
M. Furlanut ◽  
G. Fiandini ◽  
P. Melacini ◽  
R. Padrini ◽  
M. Ferrari
Keyword(s):  
Guinea Pig ◽  
Phospholipase C ◽  
Mechanical Activity ◽  
Taenia Coli

scholarly journals Effects of epidermal growth factor, interleukin 1 and nitric oxide on prostaglandin production by guinea-pig uterus

Reproduction ◽  
2002 ◽  
pp. 317-322 ◽  
Author(s):  
JE Keeble ◽  
NL Poyser
Keyword(s):  
Nitric Oxide ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Guinea Pig ◽  
Sodium Nitroprusside ◽  
Spontaneous Activity ◽  
Contractile Activity ◽  
Prostaglandin Production ◽  
Epidermal Growth

Initial experiments in the present study investigated the effects of epidermal growth factor (EGF), interleukin 1beta (IL-1beta) and sodium nitroprusside (a nitric oxide donor) on the output of prostaglandins from guinea-pig uterus on day 7 of the oestrous cycle. Superfusion of day 7 guinea-pig uterus in vitro with either EGF or sodium nitroprusside increased the output of PGF(2alpha) and 6-keto-PGF(1alpha), but not of PGE(2). IL-1beta had no effect on the output of these three prostaglandins. EGF still increased the output of PGF(2alpha), but did not increase the output of 6-keto-PGF(1alpha) in a calcium-depleted superfusate. Subsequent experiments investigated the effect of sodium nitroprusside on contractile activity of day 7 guinea-pig uterus. Basal spontaneous activity of both the intact uterus and isolated myometrium superfused in vitro was low. Sodium nitroprusside increased the contractile activity of these tissues two- to fourfold. EGF did not affect the contractile activity of the uterus, indicating that sodium nitroprusside-induced contractions are not due to increased prostaglandin production. Overall, the findings indicate that EGF and nitric oxide may act as mediators in the mechanism by which oestradiol acting on a progesterone-primed uterus stimulates the increase in PGF(2alpha) production by the guinea-pig uterus necessary for luteolysis. Nitric oxide may increase the spontaneous activity of the uterus when this activity is low.

Distribution and motor effect of VIP in female genital tract

1981 ◽  
Vol 240 (1) ◽  
pp. E32-E36 ◽  
Author(s):  
B. Ottesen ◽  
J. J. Larsen ◽  
J. Fahrenkrug ◽  
M. Stjernquist ◽  
F. Sundler
Keyword(s):  
Guinea Pig ◽  
Tissue Concentration ◽  
Female Genital Tract ◽  
Physiological Role ◽  
Nerve Fibers ◽  
Mechanical Activity ◽  
Nervous Control ◽  
Uterine Muscle ◽  
Female Genital

The distribution and concentration of vasoactive intestinal polypeptide (VIP) in different parts of the female genital organs from various species (cat, goat, pig, rabbit, rat, and guinea pig) were studied by means of immunohistochemistry and immunochemistry. In addition, the effect of VIP on the mechanical activity of uterine muscle was investigated in vitro. VIP immunoreactive nerve fibers innervating vessels and smooth muscle cells were fairly numerous in the genital organs of the cat and goat and less numerous in the pig, rabbit, rat, and guinea pig. In all species studied, VIP-containing nerves were most numerous in the cervix. The tissue concentration of VIP measured by immunochemistry was in agreement with the immunohistochemical findings. VIP inhibited the mechanical uterine activity in the cat, goat, pig, and rabbit, whereas only minimal effects were obtained in the rat and guinea pig. This difference between the species corresponded to the number of VIP-containing nerves in the uterine muscle. The data support the hypothesis that VIP may play a physiological role in the local nervous control of the uterine mechanical activity.

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