| 1. |
- Sjöberg, Trygve, et al.
(författare)
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Antagonism of thromboxane receptor induced contractions in isolated human groin lymphatics
- 1989
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Ingår i: Lymphology. - 0024-7766. ; 22:3, s. 135-140
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Tidskriftsartikel (refereegranskat)abstract
- In vitro studies were performed on lymphatics obtained from the groin in 19 patients undergoing vascular surgery. The lymphatics were mounted in tissue baths, and isometric contractions were induced by increasing concentrations of the thromboxane A2 (TXA2) mimetic U-46619. In comparison to K+ (124mM)-induced contraction, which were used as an internal standard, the response to U-46619 had an Emax of 105 +/- 5.9%. The pEC50-value was 8.14 +/- 0.09. The effects of two thromboxane receptor (TP-receptor) antagonists, L-636,499 and BM-13,505, were investigated. Both antagonists caused concentration-dependent right-ward shifts without depression of Emax of the U-46619 concentration-response curves. The slopes of the regression lines in a Schild plot for both antagonists did not differ from one, indicating competitive antagonism. The pA2-value of BM-13,505 (7.89) was 65 times higher than that of L-636,499 (6.08). The results suggest that the receptor involved in the prostanoid contraction in human groin lymphatics is of the TP-subtype.
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| 2. |
- Sjöberg, Trygve, et al.
(författare)
-
Contractile response in isolated human groin lymphatics
- 1987
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Ingår i: Lymphology. - 0024-7766. ; 20:3, s. 152-160
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Tidskriftsartikel (refereegranskat)abstract
- Lymphatics from the human superficial groin removed at operation in 21 patients (one with lymphedema) were examined in vitro. Histochemically no nerves were identified with either specific catecholamine fluorescence or immunoreactivity to tyrosine hydroxylase or dopamine beta-hydroxylase. Ring preparations of the lymphatics were mounted in tissue baths and isometric induced contractions were recorded after administration of K+ (124 mM), acetylcholine, selected amines and prostanoids. Noradrenaline (NA), adrenaline, dopamine, and acetylcholine had no or only weak contractile effects. In some segments, serotonin induced contractions. Prostaglandin E2 showed no contractile effect and prostaglandin F2 alpha induced contraction in most of the tested lymphatics. The prostaglandin-endoperoxide analogue U44069 uniformly elicited marked concentration-dependent contraction. In the lymphatic segment from the patient with lymphedema, a slightly greater contractile response to NA and serotonin was observed. The results overall suggest an absence of sympathetic innervation and contraction-mediating alpha adrenergic receptors in human superficial groin lymphatics, and support that certain prostanoids may be important regulators of human lymphatic contractility.
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| 3. |
- Sjöberg, Trygve, et al.
(författare)
-
Contractility of human leg lymphatics during exercise before and after indomethacin
- 1989
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Ingår i: Lymphology. - 0024-7766. ; 22:4, s. 186-193
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Tidskriftsartikel (refereegranskat)abstract
- Subcutaneous lymphatics in the lower leg were catheterized in the retrograde direction in 6 healthy male subjects. The catheter was connected to a pressure transducer, and pressure was measured during three stages of exercise including standing, tip-toeing, and running in place. Before the third stage, indomethacin (50mg) was given i.v. Rhythmic pressure waves were registered in each subject. During the second stage, when the subjects were "warmed up," the frequency (min-1) was 2.4 +/- 0.5 (mean +/- SEM). The corresponding values during tip-toeing and running were 5.8 +/- 0.7 (p less than 0.05) and 5.4 +/- 0.5 (p less than 0.05), respectively. The amplitudes (mean values between 3.2-4.7mmHg while standing) were not consistently altered during tip-toeing or running in any of the three stages. During standing there was a negative correlation between frequency and amplitude. No such correlation was found during tip-toeing or running, or after injection of indomethacin. Indomethacin did not significantly alter any of the measured parameters, but in two subjects the frequencies and amplitudes were decreased (about 50%) during standing, tip-toeing, and running.
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