CONCENTRATIONS OF 6-OXO-PROSTAGLANDIN F1α AND THROMBOXANE B2 IN THE TRACHEAL FLUID OF FOETAL SHEEP

1978 ◽  
Vol 79 (3) ◽  
pp. 403-404
Author(s):  
M. D. MITCHELL ◽  
J. S. ROBINSON
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
University Of Oxford ◽  
Obstetrics And Gynaecology ◽  
Nuffield Department ◽  
John Radcliffe Hospital ◽  
Prostaglandin F ◽  
Tracheal Insufflation ◽  
Prostaglandins E

Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU (Received 21 July 1978) Prostaglandins of the E and F series have been shown to relax or contract respectively guinea-pig trachea and recently it has been demonstrated that the prostaglandin endoperoxides PGG2 and PGH2 (immediate precursors of prostaglandins E and F) have far greater potency in contracting tracheal smooth muscle than prostaglandin F (Hamberg, Svensson, Hedqvist, Strandberg & Samuelsson, 1976). Furthermore, both thromboxane A2 and prostacyclin can also elicit contraction of the trachea with thromboxane A2 being considerably more active (Omini, Moncada & Vane, 1977; Svensson, Strandberg, Tuvemo & Hamberg, 1977). Administration of thromboxane A2 has been shown to raise the tracheal insufflation pressure in guinea-pigs (Svensson et al. 1977) and indeed its stable metabolite thromboxane B2 is released in relatively large amounts from sensitized guinea-pig lungs when challenged with antigen (Dawson, Boot, Cockerill,

PRODUCTION OF THROMBOXANE B2 BY INTRA-UTERINE TISSUES FROM PREGNANT GOATS IN VITRO

1978 ◽  
Vol 78 (1) ◽  
pp. 159-160 ◽  
Author(s):  
M. D. MITCHELL ◽  
A. P. F. FLINT ◽  
E. J. KINGSTON ◽  
G. D. THORBURN ◽  
J. S. ROBINSON
Keyword(s):  
Thromboxane B2 ◽  
Basic Data ◽  
University Of Oxford ◽  
Obstetrics And Gynaecology ◽  
Nuffield Department ◽  
John Radcliffe Hospital ◽  
Prostaglandin F ◽  
Prostaglandins E

Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU (Received 9 February 1978) It has been shown that prostaglandins play an important role in the mechanism of parturition in many species, including the goat (Currie & Thorburn, 1977; Thorburn, Challis & Robinson, 1977). Recently we have demonstrated that intra-uterine tissues from pregnant goats, when superfused in vitro, produce prostaglandins E and F (PGE, PGF) and 13,14-dihydro-15-oxo-prostaglandin F at various rates (Mitchell, Flint, Robinson & Thorburn, 1978). The exciting discoveries of two potent prostaglandin-like compounds, thromboxane A2 (TXA2; Hamberg, Svensson & Samuelsson, 1975) and prostacyclin (PGI2; Moncada, Gryglewski, Bunting & Vane, 1976), have radically altered our thinking on prostaglandins and basic data are urgently required concerning these compounds. Since prostaglandin endoperoxides are the immediate precursors of both prostaglandins and TXA2 (and PGI2) and since TXA2 has been shown to cause contraction of a number

UTERINE TISSUES FROM PREGNANT GOATS PRODUCE 6-OXO-PROSTAGLANDIN F1α IN VITRO

1978 ◽  
Vol 79 (3) ◽  
pp. 401-402 ◽  
Author(s):  
M. D. MITCHELL ◽  
A. P. F. FLINT ◽  
B. R. HICKS ◽  
E. J. KINGSTON ◽  
G. D. THORBURN ◽  
...  
Keyword(s):  
Biological Systems ◽  
Aqueous Media ◽  
Late Pregnancy ◽  
University Of Oxford ◽  
Obstetrics And Gynaecology ◽  
Nuffield Department ◽  
John Radcliffe Hospital ◽  
Prostaglandin F

Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Headington, Oxford, 0X3 9DU (Received 21 July 1978) It now seems likely that prostaglandins play an important role in the mechanisms of parturition in many species (Flint & Hillier, 1976; Thorburn, Challis & Robinson, 1977), including the goat (Thorburn, Nicol, Bassett, Shutt & Cox, 1972; Currie & Thorburn, 1977). This evidence has been further strengthened by the demonstration of the production of prostaglandins in vitro by uterine tissues from goats during late pregnancy (Mitchell, Flint, Robinson & Thorburn, 1978b). The recent discovery of prostacyclin (Moncada, Gryglewski, Bunting & Vane, 1976) has added a new dimension to prostaglandin research since in some biological systems it has a greater potency than other prostaglandins (Moncada et al. 1976; Omini, Moncada & Vane, 1977). Prostacyclin is highly unstable in aqueous media and degrades spontaneously to 6-oxo-prostaglandin F1α (6-oxo-PGF1α; Johnson, Morton, Kinner, Gorman,

PRODUCTION OF PROSTAGLANDINS BY THE GUINEA-PIG UTERUS

1972 ◽  
Vol 54 (1) ◽  
pp. 147-159 ◽  
Author(s):  
N. L. POYSER
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Oestrous Cycle ◽  
Prostaglandin E ◽  
Prostaglandin F

SUMMARY The production of prostaglandins by the uterus and the resting levels of prostaglandins in the uterus on selected days of the oestrous cycle were determined in guinea-pigs. Prostaglandin F2α was detectable in the guinea-pig uterus in small amounts on days 13, 14 and 15 of the cycle. Prostaglandin E2 was present in even smaller amounts on days 14 and 15. The homogenized guinea-pig uterus had the ability to biosynthesize prostaglandins, from endogenous precursors, during incubation on every day of the cycle studied. Four to six times more prostaglandin F2α than E2 was produced on any one day with the amounts of prostaglandins formed increasing towards the end of the oestrous cycle. Indomethacin inhibited the biosynthesis of prostaglandins by the guinea-pig uterus. The implications of these findings are discussed.

EFFECT OF SOMATOSTATIN ON THE CONCENTRATION OF GROWTH HORMONE IN THE PLASMA OF FOETAL SHEEP

1978 ◽  
Vol 78 (3) ◽  
pp. 453-454 ◽  
Author(s):  
I. C. McMILLEN ◽  
G. JENKIN ◽  
G. D. THORBURN ◽  
J. S. ROBINSON
Keyword(s):  
Growth Hormone ◽  
Pituitary Gland ◽  
Medical Research ◽  
Pituitary Stalk ◽  
Obstetrics And Gynaecology ◽  
Nuffield Department ◽  
John Radcliffe Hospital ◽  
Ovine Placenta

Nuffield Institute for Medical Research and Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Headington, Oxford, 0X3 9DU (Received 6 April 1978) Growth hormone (GH) has been located in the ovine foetal pituitary gland by day 50 of gestation (Stokes & Boda, 1968). The concentration of GH in the plasma of foetal sheep is ten times higher than the postnatal value, increasing from 40 ng/ml on day 100 of gestation to 100–120 ng/ml on day 140 (Bassett, Thorburn & Wallace, 1970). After foetal hypophysectomy, the concentration of GH falls to < 2 ng/ml, indicating that it originates in the foetal pituitary gland (Wallace, Stacey & Thorburn, 1973). Labelled GH does not cross the ovine placenta (Wallace et al. 1973). After sectioning the foetal pituitary stalk, the concentration of GH in the foetal plasma drops to approximately 5 ng/ml (Wallace et al. 1973), which implies that the secretion of GH

scholarly journals Phasic and Tonic Smooth Muscle Function of the Partially Obstructed Guinea Pig Intestine

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Jingbo Zhao ◽  
Donghua Liao ◽  
Jian Yang ◽  
Hans Gregersen
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Muscle Function ◽  
Circumferential Stress ◽  
Outer Diameter ◽  
Dependent Manner ◽  
Contraction Force ◽  
Jejunal Segment ◽  
Smooth Muscle Function

This study was to generate phasic and tonic stress-strain curves for evaluation of smooth muscle function in the obstructed guinea pig jejunum. Partial and sham obstruction of the jejunum in guinea pigs was created surgically, with guinea pigs not being operated on served as normal controls. The animals survived 2, 4, 7, and 14 days, respectively. The jejunal segment was distended to 10 cm H2O. The pressure and outer diameter changes were recorded. Passive conditions were obtained by using papaverine. Total phasic, tonic, and passive circumferential stress and strain were computed from the diameter and pressure data with reference to the zero-stress-state geometry. The active phasic and tonic stresses were defined as the total phasic and tonic stress minus the passive stress. The thickness of intestinal muscle layers increased in a time-dependent manner after obstruction. The amplitude of passive, total phasic, total tonic, active phasic, and active tonic circumferential stresses increased as function of strain 7 days after obstruction. However, when normalized to muscle layer thickness, the amplitude of active stresses did not differ among the groups. In conclusion, the long-term-obstructed intestine exhibits increased total smooth muscle contraction force. However, the contraction force per smooth muscle unit did not increase.

Effects of Baicalein on Prostanoid Generation from the Lung and Contractile Responses of the Trachea in Guinea Pig

1997 ◽  
Vol 25 (01) ◽  
pp. 37-50 ◽  
Author(s):  
Koji Miyamoto ◽  
Takeshi Katsuragi ◽  
Parhat Abdu ◽  
Tatsuo Furukawa
Keyword(s):  
High Performance Liquid Chromatography ◽  
Smooth Muscle ◽  
Liquid Chromatography ◽  
Guinea Pig ◽  
High Performance ◽  
Hplc Analysis ◽  
Antigen Challenge ◽  
Cyclooxygenase Inhibitor ◽  
Prostaglandin F ◽  
Stimulation Of

Effects of baicalein on release of slow reacting substance of anaphylaxis (SRS-A) or leukotriene (L T) from the sensitized guinea pig lung after antigen challenge and tonus of guinea pig tracheal muscles were studied. Baicalein inhibited release of SRS-A from sensitized guinea pig lung after antigen challenge. High-performance liquid chromatography (HPLC) analysis revealed that released SRS-A consisted of LTC 4 and D 4. Baicalein also reduced release of LTC 4 and D 4 from the sensitized lung after antigen challenge. Baicalein relaxed the isolated guinea pig tracheal smooth muscle contracted by LTD 4, carbachol or histamine. However, this compound produced a contraction when the tracheal muscle was contracted by prostaglandin F 2α ( PGF 2α). This contraction by baicalein was abolished by pretreatment with indomethacin, a cyclooxygenase inhibitor. Baicalein elicited a relaxation in the normal non-sensitized tracheal preparation but a contraction in the tissue isolated from actively sensitized guinea pig in 4 among 7 cases. Baicalein also produced a contraction in the trachea pretreated with phorbol dibutyrate and contracted by carbachol, which was eliminated after treatment with indomethacin. The results suggest that baicalein exerts action via, at least, two different mechanisms, the inhibition of releasing SRS-A (LTs) and direct relaxing effects on the trachea. Besides, baicalein seems to produce contraction under certain conditions, which may involve stimulation of the cyclooxygenase pathway.

PROGESTERONE, PROSTAGLANDIN F2α, AND OESTRADIOL IN THE UTERO-OVARIAN VENOUS PLASMA OF NON-PREGNANT AND EARLY, UNILATERALLY PREGNANT GUINEA-PIGS

1975 ◽  
Vol 67 (2) ◽  
pp. 225-229 ◽  
Author(s):  
F. R. BLATCHLEY ◽  
F. M. MAULE WALKER ◽  
N. L. POYSER
Keyword(s):  
Guinea Pig ◽  
Early Pregnancy ◽  
Guinea Pigs ◽  
Prostaglandin F2α ◽  
Progesterone Secretion ◽  
Prostaglandin F ◽  
Venous Plasma

SUMMARY Levels of progesterone, prostaglandin F2α (PGF2α) and oestradiol in the utero-ovarian venous plasma of non-pregnant and early, unilaterally pregnant guinea-pigs were compared. Progesterone levels fell from day 12 to day 15 in the non-pregnant animals, while levels of PGF2α and oestradiol increased during this period. In contrast, in the pregnant guinea-pigs, progesterone levels remained high up to day 15 and PGF2α and oestradiol levels remained low in plasma from both the pregnant and non-pregnant sides. These findings support the hypothesis that the guinea-pig conceptus secretes an anti-luteolytic factor in early pregnancy, which reduces the amount of PGF2α produced by the uterus and released into the uterine veins and thereby allows luteal maintenance and continued progesterone secretion. Oestradiol, in the presence of progesterone, is regarded as the physiological stimulus for normal uterine PGF2α synthesis and release. Consequently, the inhibition of ovarian oestradiol secretion seen in early pregnancy is probably at least part of the mechanism by which the anti-luteolytic factor produced by the conceptus reduces PGF2α synthesis by and release from the uterus.

Changes of gap junctions in myometrium of guinea pig at parturition and abortion

1982 ◽  
Vol 60 (3) ◽  
pp. 335-341 ◽  
Author(s):  
R. E. Garfield ◽  
E. E. Daniel ◽  
M. Dukes ◽  
J. D. Fitzgerald
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Gap Junctions ◽  
Gap Junction ◽  
Electron Micrographs ◽  
Guinea Pigs ◽  
Muscle Cells ◽  
Similar Increase ◽  
Junction Area

Myometrial tissues from guinea pigs were quantitatively examined for gap junctions in electron micrographs. Small numbers of gap junctions were present between smooth muscle cells in myometria of pregnant guinea pigs at days 50 and 65 of gestation. The junctions increased in number and size at parturition on day 69 and decreased again to control levels 24 h after parturition. A similar increase in junctions occurred when abortion was induced by 16,16-dimethylprostaglandin E2 (PGE2) on day 65. There were no consistent or significant differences in numbers of gap junctions from myometrium taken over sites of placental attachment and from other sites. These results together with previous studies suggest that an increase in myometrial gap junction area is associated with and may be essential for parturition in guinea pigs, but the control of their development may differ from that in other mammals.

Benign Mesenchymoma of the Heart in the Guinea Pig

1968 ◽  
Vol 5 (2) ◽  
pp. 97-101 ◽  
Author(s):  
Robert F. McConnell ◽  
Raymond D. Ediger
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
The Other ◽  
Breeding Colony ◽  
Muscle Tissues ◽  
Single Mass

Thirty-six hundred ninety-eight guinea pigs of the Dunkin-Hartley strain from the breeding colony at Fort Detrick were necropsied. Four females had mesenchymomas of the heart. The tumors were similar histologically and were composed of multiple benign mesenchymal tissues which were amalgamated into a single mass. One tumor was composed of fibrous, angiomatous, adipose, cartilagenous, osscous, hematopoietic, myxomatous, and possibly smooth muscle tissues. Smooth muscle and myxomatous tissues were not found in the other tumors. All were benign and probably originated from the primitive mesenchyme of the heart.

Effect of mode of activation of human eosinophils on tracheal smooth muscle contraction in guinea pigs

1993 ◽  
Vol 264 (5) ◽  
pp. L475-L481
Author(s):  
M. E. Strek ◽  
S. R. White ◽  
T. R. Hsiue ◽  
G. V. Kulp ◽  
F. S. Williams ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Human Peripheral Blood ◽  
Total Content ◽  
Smooth Muscle Contraction ◽  
Tracheal Smooth Muscle ◽  
Kinetic Assay ◽  
Lipoxygenase Pathway ◽  
Threshold Response

We studied the relationship between mode of activation of isolated human eosinophils and in situ responsiveness in isolated tracheal smooth muscle (TSM) of guinea pigs. Human peripheral blood eosinophils were activated with either 10(-7) M phorbol myristate acetate (PMA) or 10(-6) M formyl-methionyl-leucyl-phenylalanine (fMLP) + 5 micrograms/ml cytochalasin B (CYB), and activation was confirmed by measurement of eosinophil peroxidase (EPO) secretion by kinetic assay. EPO secretion was similar after activation with fMLP+CYB (10.2 +/- 3.2% of total eosinophil content) and PMA (10.0 +/- 2.8% of total content; P = NS). Topical application of 6 x 10(6) eosinophils/cm2 activated with fMLP+CYB to the TSM segment caused 0.51 +/- 0.14 g/cm active tension (AT) in five preparations (P < 0.03 vs. baseline); cells activated with PMA caused no contractile response (0.04 +/- 0.03 g/cm AT, P = NS vs. baseline). Both PMA- and fMLP+CYB-activated cells caused augmentation of muscarinic responsiveness of guinea pig trachealis. The dose of intravenous acetylcholine required to cause a threshold response (ED0.3) was -7.3 +/- 0.1 log mol/kg at baseline vs. -8.7 +/- 0.5 log mol/kg after treatment with fMLP+CYB-activated eosinophils (P = 0.05) and -6.9 +/- 0.1 log mol/kg at baseline vs. -7.5 +/- 0.1 log mol/kg after PMA-activated cells (P < 0.01). Both AT and augmented muscarinic responsiveness were blocked by pretreating the eosinophils with 200 microM A-63162, an inhibitor of 5-lipoxygenase, before activation with fMLP+CYB. We demonstrate that eosinophils activated comparably (as assessed by EPO secretion) cause augmented muscarinic responsiveness and/or direct contraction of guinea pig TSM through secretion of a product of the 5-lipoxygenase pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

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