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Abstract
A cautionary tale
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Affiliation(s)
- R G Andersson
- Department of Surgery, Clinical Sciences Lund, Lund University Hospital, SE-221 85 Lund, Sweden.
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Persson K, Whiss PA, Nyhlén K, Jacobsson-Strier M, Glindell M, Andersson RG. Nitric oxide donors and angiotensin-converting enzyme inhibitors act in concert to inhibit human angiotensin-converting enzyme activity and platelet aggregation in vitro. Eur J Pharmacol 2000; 406:15-23. [PMID: 11011027 DOI: 10.1016/s0014-2999(00)00647-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study investigates the effects of exogenous and endogenous nitric oxide (NO) on human circulating and endothelial angiotensin-converting enzyme activity and platelet aggregation. The NO donor S-nitroso-N-acetylpenicillamine (10(-8)-10(-6) M) significantly and dose-dependently inhibited serum angiotensin-converting enzyme activity. The concomitant addition of S-nitroso-N-acetylpenicillamine to angiotensin-converting enzyme inhibitor-treated (captopril or enalaprilat) serum, further reduced angiotensin-converting enzyme activity. In cultured endothelial cells from human umbilical veins (HUVECs), both S-nitroso-N-acetylpenicillamine and 3-morpholinosydnonimine (SIN-1) significantly reduced angiotensin-converting enzyme activity. An additative effect was seen with a combined treatment of captopril and S-nitroso-N-acetylpenicillamine. Treatment with the NO synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) did not affect angiotensin-converting enzyme activity. Thrombin inhibited endothelial angiotensin-converting enzyme activity, an effect that was abolished when cells were pretreated with L-NMMA. Adenosine 5'-diphosphate (ADP)-induced platelet aggregation was inhibited with S-nitroso-N-acetylpenicillamine, SIN-1 and nitroglycerine. Captopril did not affect aggregation, while a high concentration of enalaprilat (10(-4) M) reduced it. The concomitant addition of 10(-5) M angiotensin-converting enzyme inhibitor to NO donor-treated platelets resulted in a further reduction of platelet aggregation. This effect was most evident with SIN-1 and enalaprilat. In conclusion, both exogenous and endogenous NO inhibit human angiotensin-converting enzyme activity. NO donors and angiotensin-converting enzyme inhibitors act in concert to inhibit angiotensin-converting enzyme and platelet aggregation.
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Affiliation(s)
- K Persson
- Division of Pharmacology, Department of Medicine and Care, Faculty of Health Sciences, Linköping University, SE-581 85, Linköping, Sweden.
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Fägerstam JP, Whiss PA, Ström M, Andersson RG. Expression of platelet P-selectin and detection of soluble P-selectin, NPY and RANTES in patients with inflammatory bowel disease. Inflamm Res 2000; 49:466-72. [PMID: 11071121 DOI: 10.1007/s000110050618] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE AND DESIGN P-selectin, a membrane glycoprotein which is expressed on activated platelets and endothelial cells, plays a crucial role in the inflammatory response. The main action is adhesion of leukocytes, facilitation of diapedesis and induction of cytokine production from monocytes (MCP-1 and IL-8), mediated via RANTES released from activated platelets. An abnormal platelet activity has been reported in patients with ulcerative colitis (UC) and Crohn's disease (CD), jointly referred to as inflammatory bowel disease (IBD), which could have an aggravating influence on the inflammatory response. In addition, an up-regulation of platelet IL-8 receptors among patients with IBD has been reported. To reveal a presumptuous platelet dysfunction we analysed the expression of platelet surface P-selectin at resting state and after stimulation with thrombin, collagen, epinephrine and interleukin 8 (IL-8), and plasma levels of soluble P-selectin, neuropeptide Y (NPY) and RANTES in patients with IBD. SUBJECTS Blood from twelve healthy subjects (control group) and twenty-one patients with IBD who had not taken any anti-platelet drugs or steroids were analysed. METHODS Patients were sub-grouped according to disease entity, disease activity and 5ASA medication. Surface P-selectin expression on isolated human platelets and plasma P-selectin, NPY and RANTES were analysed with ELISA. All values are presented as mean +/- standard error of the mean (SEM). Mann-Whitney U test and Wilcoxon matched rank test were used for statistical analyses. RESULTS Patients with IBD in remission (n = 9) had higher basal P-selectin expression, 0.38+/-0.04, compared to the control group (n = 12), 0.22+/-0.03,p < 0.01. UC patients (n = 16) showed down-regulation of P-selectin expression after stimulation with IL-8, 0.26+/-0.03 to 0.22+/-0.02, p < 0.05. No significant differences could be observed concerning soluble P-selectin and NPY in plasma. Patients with 5ASA (n = 12) had lower levels of plasma RANTES, 2.39+/-0.06 microg/l, compared to the control group (n = 12), 3.29+/-0.19 microg/l, p < 0.01, and patients without 5ASA (n = 9), 2.90+/-0.17 microg/l, p < 0.05. CONCLUSIONS Patients with IBD in remission have higher basal platelet surface P-selectin expression. An exaggerated platelet activity with increased expression of platelet P-selectin and release of inflammatory mediators such as RANTES, which is chemotactic and induce chemokine production, could have a reinforcing and aggravating influence on the inflammatory response and increase the susceptibility to IBD. In addition IL-8 has a down-regulating effect on platelet surface P-selectin expression and 5ASA medication seems to lower plasma RANTES. If 5ASA is responsible for lowering the concentration of RANTES this could be one of the beneficial outcomes of 5ASA medication.
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Affiliation(s)
- J P Fägerstam
- University of Linköping, Department of Medicine and Care, Faculty of Health Sciences, Sweden.
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Mårtensson LG, Andersson RG. A pharmacological interaction between melatonin and the alpha 2-adrenoceptor in cuckoo wrasse melanophores. Adv Exp Med Biol 2000; 460:221-8. [PMID: 10810517 DOI: 10.1007/0-306-46814-x_24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- L G Mårtensson
- Department of Pharmacology, Faculty of Health Sciences, Linköping, Sweden
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Abstract
Pigment aggregation in melanophores of Labrus ossifagus is controlled by an alpha2-adrenoceptor and is somehow modulated by melatonin. The signal transduction mechanisms seem to involve both an attenuation of cAMP and an increase in intracellular Ca2+, inhibiting protein kinase A or activating a phosphatase, respectively. These effects result in dephosphorylation, which in turn induces aggregation. Various alpha2-adrenoceptor agonists attenuate cAMP levels or increase the concentration of intracellular Ca2+. Noradrenaline, for example, lowers cAMP but does not affect the calcium signal whereas B-HT 920, an alpha2-adrenoceptor specific agonist, does not induce a cAMP decrease but does appear to induce an increase in intracellular Ca2+. This later inference is drawn from experiments with BAPTA/AM, an intracellular calcium chelator, which counteracts the aggregation induced by B-HT 920. Interestingly, the very potent alpha2-adrenoceptor agonist medetomidine apparently activates both signal transduction pathways, which could explain its high efficacy in producing aggregation. Melatonin itself does not cause pigment aggregation, but it potentiates noradrenaline-induced aggregation. It has been suggested that melatonin receptors and alpha2-adrenoceptors follow the same signal transduction pathway, i.e. an attenuation of cAMP. In our experiments, melatonin did not reduce cAMP levels; instead it appears to increase Ca2+ concentration, since melatonin-potentiated aggregation was inhibited by BAPTA/AM. Thus, aggregation amplified by melatonin is probably not mediated by a further decrease in cAMP, but by the same signal transduction mechanism as B-HT 920, i.e. an increase in Ca2+. This further strengthens the suggestion that melatonin and B-HT 920 bind to the same site, but it is unclear if that particular site is on the melatonin receptor or the alpha2-adrenoceptor.
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Affiliation(s)
- L G Mårtensson
- Department of Zoology, Zoophysiology, Göteborg University, Sweden.
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Abstract
The influence of the angiotensin-converting enzyme inhibitor captopril on bradykinin-and angiotensin I-induced responses with special regard to nitric oxide (NO) was studied. Auxometric tension and angiotensin-converting enzyme activity was studied in isolated porcine iliac arteries. Captopril potentiated bradykinin-induced contraction of preparations with intact endothelium; this potentiation was not seen with the kininase I inhibitor mergepta or a bradykinin B(1)-receptor antagonist. Captopril did not affect bradykinin-induced relaxation. The captopril-mediated increase of bradykinin-induced contraction was only seen in preparations with intact endothelium, while captopril did not affect arterial strips treated with Nomega-nitro-L-arginine. Angiotensin I-induced contractions was less reduced by captopril when the strips were pretreated with Nomega-nitro-L-arginine. Both captopril and the NO donor S-nitroso-N-acetyl-penicillamine inhibited angiotensin-converting enzyme activity. An additional reduction in angiotensin-converting enzyme activity was seen when S-nitroso-N-acetyl-penicillamine was added to captopril-treated preparations. In conclusion, captopril increased bradykinin-induced contraction in a NO-dependent manner. This potentiation is probably mediated by the increased metabolism of bradykinin by kininase I, and the additive angiotensin-converting enzyme inhibitory effect of captopril and NO.
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Affiliation(s)
- K Persson
- Division of Pharmacology, Department of Medicine and Care, Faculty of Health Sciences, Linköping University, S-581 85, Linköping, Sweden.
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Schmekel B, Rydberg I, Norlander B, Sjöswärd KN, Ahlner J, Andersson RG. Stereoselective pharmacokinetics of S-salbutamol after administration of the racemate in healthy volunteers. Eur Respir J 1999; 13:1230-5. [PMID: 10445595 DOI: 10.1034/j.1399-3003.1999.13f04.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Racemic R,S-salbutamol is taken to relieve bronchial constriction. Only the R-enantiomer has bronchodilating properties. The S-enantiomer has been proposed to cause in vitro bronchial hyperreactivity in guinea-pigs. Stereoselective elimination of salbutamol has been shown, with S-salbutamol being eliminated at a slower rate than R-salbutamol. This study questioned whether rates of stereoselective elimination were similar after oral or lung delivery, and whether the S:R ratio would increase after repeated inhalations in a situation resembling a common clinical use. Eighteen healthy volunteers received single-dose racemic salbutamol as a solution instilled in the trachea during anaesthesia, as inhaled micronized powder and/or as ingested tablets. Five volunteers inhaled repeated doses of racemic salbutamol. Concentrations in plasma and urine were measured using a technique which allowed chiral separation of samples with concentrations as low as 0.1 ng x mL(-1). The bioavailability of S-salbutamol was significantly higher than that of R-salbutamol after the different modes of administration. Stereoselective elimination was more pronounced after oral administration than after inhalation. Repeated inhalations resulted in successive increases in the S:R ratio as steady state was approached. In conclusion, the clinical consequences of increasing plasma concentrations of S-salbutamol need to be further assessed.
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Affiliation(s)
- B Schmekel
- Dept. of Clinical Physiology, University Hospital, Linköping, Sweden
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Whiss PA, Andersson RG, Srinivas U. Kinetics of platelet P-selectin mobilization: concurrent surface expression and release induced by thrombin or PMA, and inhibition by the NO donor SNAP. Cell Adhes Commun 1998; 6:289-300. [PMID: 9865463 DOI: 10.3109/15419069809010788] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Activated platelets and endothelium surface express the cell adhesion molecule P-selectin (CD62P), which plays an important role in mediating interactions with leukocytes. Increased levels of a functional soluble form of P-selectin (sP-selectin) have been reported in several pathological states but it is not clear whether this circulating sP-selectin originates from platelets and/or endothelial cells. Here we describe the concurrent kinetics of intracellular storage, surface expression and release of platelet P-selectin induced by thrombin or the protein kinase C activator PMA. Platelet activation with submaximal concentrations of thrombin (0.1 U/ml) resulted in a rapid decrease of intracellular P-selectin. This decrease of intracellular P-selectin concurred with a gradual increase of surface expression and an initial increase of sP-selectin. Our results indicate that intracellular stores of P-selectin were only partly mobilized upon activation with submaximal concentrations of thrombin. A high concentration of thrombin (1.0 U/ml) induced a rapid and nearly total decrease of intracellular stores and a more pronounced, but transient, increase of surface expression. The release of P-selectin was fast and occurred during the initial activation phase. The NO donor SNAP inhibited both surface expression and release of platelet P-selectin in a similar manner. PMA (0.1-1.0 microM) mediated a more slow, gradual and sustained surface expression and release of P-selectin than thrombin. Thus, surface expression and release of platelet P-selectin show different kinetics depending on the mode of activation.
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Abstract
Bradykinin-induced responses were studied in isolated porcine iliac arteries. Relaxation was endothelium dependent and seen at low concentrations (10(-10)-10(-8) M) of bradykinin. It was inhibited by the bradykinin B2-receptor antagonist icatibant (HOE-140) and by the nitric oxide synthase inhibitor Nomega-nitro-L-arginine. Bradykinin-induced relaxation was significantly potentiated by the kininase I carboxypeptidase inhibitor mergepta (10(-6) M). Bradykinin (>10(-7) M) elicited contraction of preparations with or without endothelium. The contraction was abolished by indomethacin but was not affected by the thromboxane A2/prostaglandin H2-receptor antagonist SQ 29,548. Icatibant and the bradykinin B1-receptor antagonist desArg9[Leu8]bradykinin significantly decreased bradykinin-induced contraction regardless of endothelial function. The contraction also was decreased by treatment with mergepta. The bradykinin B1-receptor agonist desArg9-bradykinin contracted endothelium-denuded arterial strips. This contraction was significantly decreased by desArg9[Leu8]bradykinin but not by icatibant. The desArg9-bradykinin-induced contraction also was inhibited by the protein-synthesis inhibitor cycloheximide. Neither bradykinin-induced relaxation nor contraction was affected by the ACE inhibitors enalaprilat or cilazaprilat. In conclusion, bradykinin-induced relaxation of isolated porcine iliac arteries was mediated by endothelial bradykinin B2 receptors and mainly nitric oxide. Bradykinin-induced contraction was endothelium independent, indomethacin sensitive, and probably mediated by bradykinin B1 (inducible) and B2 receptors located in the vascular smooth-muscle layer. Kininase I carboxypeptidase, and not ACE, is the main enzyme responsible for bradykinin degradation in these vessels.
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Affiliation(s)
- K Persson
- Department of Medicine and Care, Faculty of Health Sciences, Linköping, Sweden
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Lindström EG, Andersson RG. Neurokinin A-LI release after antigen challenge in guinea-pig bronchial tubes: influence of histamine and bradykinin. Br J Pharmacol 1997; 122:417-22. [PMID: 9351496 PMCID: PMC1564948 DOI: 10.1038/sj.bjp.0701382] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. Our aim was to determine if antigen challenge stimulates sensory nerves and provokes the release of tachykinins. The involvement of histamine and bradykinin was studied by using specific receptor antagonists. Capsaicin-induced responses were also examined. Experiments were performed in vitro on tracheal and bronchial preparations from ovalbumin-sensitized guinea-pigs. 2. Characterization of ovalbumin-induced contraction, with regard to histamine and bradykinin, was carried out on airway ring preparations in the presence of phosphoramidon. The histamine H1 receptor antagonist pyrilamine reduced allergen-induced bronchial contractions by about 30%, whereas the bradykinin B2 receptor antagonist icatibant (Hoe 140) did not significantly affect the response. Combined treatment with pyrilamine (1 microM) and icatibant (0.1 microM) reduced the contractions by about 80%, indicating a synergistic inhibitory action. Tracheal preparations were not significantly affected by treatments, neither were capsaicin-induced contractions. 3. To study the outflow of tachykinins, we used a perfused bronchial-tube preparation, allowing simultaneous measurement of smooth muscle tension and mediator release. Neurokinin A-like immunoreactivity (NKA-LI) and substance P-like immunoreactivity (SP-LI) were determined by radioimmunoassay. 4. The results of the perfusion study showed an increased outflow of NKA-LI into the perfusate in response to ovalbumin (127% of basal) challenge. SP-LI determined in some of the samples showed a much lower amount (40 to 70 times lower) of SP-LI than NKA-LI. Treatment with icatibant and pyrilamine, separately and in combination, significantly reduced the ovalbumin-induced NKA-LI outflow by 38%, 26% and 22%, respectively. 5. Capsaicin-induced outflow (124% of basal) was not significantly affected by treatments (icatibant 121%, pyrilamine 107% and combined treatment 111% of basal). However, when pyrilamine was present the increased outflow was not statistically significant. 6. In conclusion, we found that allergen provocation of guinea-pig bronchi caused an increased outflow of NKA-LI that was reduced by treatment with both pyrilamine and icatibant. These findings demonstrate that the allergen-induced release of histamine and bradykinin stimulate sensory nerves and thereby increase outflow of tachykinins that contribute to the allergic reaction.
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Affiliation(s)
- E G Lindström
- Department of Medicine and Care, Faculty of Health Sciences, University of Linköping, Sweden
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Abstract
This investigation characterized the smooth muscle relaxing effect of a novel nitric oxide (NO)-releasing substance, GEA 3175 (1,2,3,4-oxatriazolium, 3-(3-chloro-2-methylphenyl)-5-[[(4-methylphenyl)sulfonyl]amino], hydroxide inner salt) on guinea-pig trachea. GEA 3175 caused a concentration-dependent relaxation of tracheal smooth muscle precontracted with acetylcholine. This effect was reversed by both okadaic acid, an inhibitor of serine/threonine-specific phosphatases, and iberiotoxin, an inhibitor of Ca2+-activated K+ channels. Furthermore, GEA 3175 had a relaxation potency similar to that of the commonly used NO-donor, S-nitroso-N-acetyl-penicillamine. On the contractile response provoked by electrical field stimulation, GEA 3175 induced a long-lasting relaxation which persisted even after repeated washing. The relaxing effect of GEA 3175 was associated with rises in guanosine 3':5'-cyclic monophosphate (cGMP). In time course studies, cGMP continued to increase with incubation time after stimulation with GEA 3175 and there was a significant elevation of cGMP even after washing. In contrast, incubation with S-nitroso-N-acetyl-penicillamine caused a transient rise in cGMP. The present investigation showed that GEA 3175 evokes long-lasting effects on contractile responses and cGMP levels in guinea-pig trachea. Our results indicate that the relaxing effect of GEA 3175 occurs through a mechanism involving phosphatases and iberiotoxin-sensitive K+ channels.
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Affiliation(s)
- I G Johansson Rydberg
- Department of Medicine and Care, Faculty of Health Sciences, LinköpingUniversity, Sweden
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Whiss PA, Andersson RG, Srinivas U. Modulation of P-selectin expression on isolated human platelets by an NO donor assessed by a novel ELISA application. J Immunol Methods 1997; 200:135-43. [PMID: 9005952 DOI: 10.1016/s0022-1759(96)00198-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Adhesion molecules such as P-selectin are potential markers for evaluating platelet activation and studying the role of cell-cell interactions in numerous biological processes related to hemostasis and inflammation. The expression of P-selectin and related molecules has previously been quantified with different techniques. As an alternative to the most common method. flow cytometry, we have developed a useful ELISA method to simultaneously analyse 96 samples for platelet expression of P-selectin. Samples may be stored for at least 7 days at 4 degrees C prior to analysis. The method is simple, reproducible, flexible and requires only standard equipment. Washed platelets (WP) from healthy male volunteers, at a concentration of 1 x 10(7)/microtiter plate well, were stimulated with various known platelet activators and fixed with 0.1% formaldehyde for 10 min. The fixed WP were centrifuged to form a confluent layer in the wells and then incubated with optimal dilutions of primary antibodies (1/2000) directed against P-selectin, CD41, CD9 and secondary antibodies conjugated with alkaline phosphatase. Our results show that P-selectin expression on WP increases significantly upon stimulation with thrombin (0.1-1.0 U/ml), ADP (10 microM) and epinephrine (100 microM). The induction of P-selectin expression by thrombin is fast and has different kinetics depending on the concentration of the agonist. Prior incubation with the nitric oxide donor SNAP (10 microM) inhibits the up-regulation of P-selectin induced by sub-maximal concentrations of thrombin (p < 0.05). This ELISA is suitable for studying the expression and regulation of P-selectin and other surface molecules on human platelets in various pathological states.
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Affiliation(s)
- P A Whiss
- Department of Pharmacology, Faculty of Health Sciences, Linköping, Sweden.
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Abstract
Pigment granule aggregation and dispersal can be studied in the melanophores of isolated scales from the cuckoo wrasse (Labrus ossifagus L.). Stimulation of a melanophore alpha2-adrenoceptor or the sympathetic nerve innervating the cell causes pigment aggregation. When the stimulation ceases, the pigment granules disperse throughout the cell. Studying this migration has been a useful tool in pharmacological research, particularly in investigations of the alpha2-adrenoceptor. Denervation of melanophores creates a receptor that is ultrasensitive to noradrenaline and melatonin. After three to four weeks of isolation, the denervated melanophores exhibit a 10(9)-fold increase in sensitivity. The efficacy of melatonin is increased from a negligible pigment-aggregation ability to the level of a full agonist. The melatonin-induced aggregation can, however, be counteracted by the alpha2-adrenoceptor antagonist yohimbine, but not by alpha1-adrenoceptor antagonist prazosin, indicating that the ultrasensitive receptor possesses alpha2-adrenoceptor features. Consequently, we conclude that the ultrasensitive receptor may represent an alpha2-adrenoceptor that has, due to denervation of the melanophore, become sensitive to melatonin.
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Affiliation(s)
- L G Moartensson
- Dept. of Pharmacology, Faculty of Health Sciences, Linköping, Sweden.
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Abstract
The hormone melatonin is known to influence the circadian rhythm, and it probably also mediates some of the physiological changes that occur in the body at night. Inasmuch as uterine activity is greater during darkness, we investigated whether melatonin could modulate uterine contractility. Biopsies were performed during caesarean sections to obtain uterine tissue from women who had reached full term. The obtained samples were mounted in organ baths, and spontaneous contractions were recorded. Melatonin alone did not change myometrial contractility, whereas melatonin in combination with noradrenaline potentiated contractions. These results may indicate that melatonin plays a role in the timing of labour, since labour often begins late in the evening.
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Affiliation(s)
- L G Mårtensson
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden.
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Grenegård M, Gustafsson MC, Andersson RG, Bengtsson T. Synergistic inhibition of thrombin-induced platelet aggregation by the novel nitric oxide-donor GEA 3175 and adenosine. Br J Pharmacol 1996; 118:2140-4. [PMID: 8864553 PMCID: PMC1909880 DOI: 10.1111/j.1476-5381.1996.tb15654.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. The influence of the novel nitric oxide-donor GEA 3175 on thrombin- and ionomycin-stimulated human platelets was investigated. The effect of GEA 3175 was compared with that of adenosine, an activator of platelet adenylyl cyclase. 2. GEA 3175 inhibited thrombin-induced secretion of ATP but did not affect aggregation; similar results were obtained with adenosine. 3. Thrombin-stimulated rises in the cytosolic free Ca2+ concentration, [Ca2+]i, were dose-dependently inhibited by GEA 3175 and adenosine. GEA 3175 and adenosine maximally reduced the initial rise in [Ca2+]i by 41% and 35%, respectively. 4. Simultaneous exposure to GEA 3175 and adenosine nearly abolished both the functional responses (i.e. aggregation and degranulation) and the rises in [Ca2+]i in thrombin-stimulated platelets. 5. Aggregation and increases in [Ca2+]i triggered in platelets by the Ca(2+)-ionophore ionomycin were only marginally affected by a combination of GEA 3175 and adenosine. 6. GEA 3175 potently increased the guanosine 3':5'-cyclic monophosphate (cyclic GMP) content in platelets but did not affect adenosine 3':5'-cyclic monophosphate (cyclic AMP) levels. Adenosine did not increase either the cyclic AMP or the cyclic GMP levels in platelets. However, adenosine and GEA 3175 combined significantly elevated the platelet cyclic AMP content. 7. The results show that simultaneous exposure to GEA 3175 and adenosine promotes potent anti-aggregatory properties in platelets in vitro. The findings suggest that blockage of the cytosolic Ca(2+)-signal, which is probably mediated by an amplified cyclic nucleotide response, is an important event during the synergistic inhibition of thrombin-induced aggregation.
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Affiliation(s)
- M Grenegård
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden
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Affiliation(s)
- F Johansson
- Department of Pharmacology, University Hospital, Linköping, Sweden
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Abstract
The melanophores of the cuckoo wrasse (Labrus ossifagus L., a teleost fish) can aggregate and disperse their pigment granules. This migration is controlled by sympathetic nerves and a postsynaptic alpha 2-adrenoceptor. Melatonin was discovered because of its ability to aggregate pigment granules, hence we used the cuckoo wrasse melanophore as a model for studying the effect of melatonin at a cellular level. We found that melatonin had no aggregating effect; instead the hormone enhanced the actions of several alpha 2-agonists, such as noradrenaline, medetomedine and clonidine. When the melanophores were pre-aggregated in vitro by use of the alpha 2-agonist B-HT 920, the aggregation was not augmented after the addition of melatonin. Instead the pre-aggregated granules were dispersed. This suggests that melatonin has affinity for an alpha 2-adrenoceptor site that can modulate the effect of alpha 2-adrenoceptor agonists.
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Affiliation(s)
- L G Mårtensson
- Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden.
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Lindström EG, Andersson RG. Morphine modulates contractile responses and neurokinin A-LI release elicited by electrical field stimulation or capsaicin in a guinea pig bronchial-tube preparation. Am J Respir Crit Care Med 1995. [DOI: 10.1164/ajrccm.151.4.7697249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Lindström EG, Andersson RG. Morphine modulates contractile responses and neurokinin A-LI release elicited by electrical field stimulation or capsaicin in a guinea pig bronchial-tube preparation. Am J Respir Crit Care Med 1995; 151:1175-9. [PMID: 7697249 DOI: 10.1164/ajrccm/151.4.1175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Excitatory nonadrenergic, noncholinergic (e-NANC) bronchoconstrictor responses have been shown to be mediated by the release of tachykinins from sensory nerves. We investigated whether bronchial-tube contractions evoked by electrical-field stimulation (EFS) or capsaicin coincided with the release of neurokinin A (NKA). We also studied the modulatory action of morphine and the ability of naloxone to affect these responses. We used a guinea pig bronchial-tube preparation denuded of epithelium. The method allows simultaneous measurement of smooth-muscle tension and mediator release. A significant release of NKA-LI, at 37.3% above the basal level, was detected in response to EFS. Morphine pretreatment was found to inhibit the release, and such inhibition was not prevented by naloxone. Contractile responses to EFS coincided with the NKA-LI release. Capsaicin stimulation evoked a significant release (35.4%) of NKA-LI, and this release was accompanied by contractions. Treatment with morphine decreased capsaicin-induced responses, and naloxone reversed the inhibitory effect. In conclusion, both capsaicin- and EFS-induced e-NANC responses were inhibited by morphine treatment. This indicates presynaptic inhibition of tachykinin release from sensory nerves. Furthermore, the ability of naloxone to reverse this inhibitory effect differed in capsaicin- and EFS-challenged preparations.
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Affiliation(s)
- E G Lindström
- Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden
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Johansson-Rydberg IG, Grundström N, Andersson RG. Pertussis toxin attenuates presynaptic inhibition of cholinergic but not nonadrenergic noncholinergic contraction in guinea pig airways. J Pharmacol Exp Ther 1995; 272:786-90. [PMID: 7853195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Several alpha-2- and opioid receptors exert their intracellular effects via a pertussis toxin-sensitive G protein. Both cholinergic and nonadrenergic noncholinergic nerve-mediated contractions of airways can be reduced by stimulation of presynaptic alpha-2- and opioid receptors. Using guinea pig trachea and bronchi, pretreated with pertussis toxin 100 micrograms/kg or 0.9% NaCl, we investigated whether these inhibitory effects on airway contractions, evoked by electrical field stimulation, are mediated via a pertussis toxin-sensitive G protein. The results indicate a difference between cholinergic and excitatory nonadrenergic non-cholinergic neurotransmission. Inhibition of cholinergic contraction via presynaptic alpha-2- and opioid receptors seems to be mediated via a pertussis toxin-sensitive G protein, whereas inhibition of nonadrenergic noncholinergic contraction is not affected by pertussis toxin.
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Affiliation(s)
- I G Johansson-Rydberg
- Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden
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22
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Ljusegren ME, Andersson RG. Protective effect of atrial natriuretic peptide on electrical-field-stimulated rat ventricular strips during hypoxia. Pharmacol Toxicol 1994; 75:337-42. [PMID: 7899254 DOI: 10.1111/j.1600-0773.1994.tb00371.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have previously shown that atrial natriuretic peptide reduces lactate accumulation in non-beating rat ventricular myocardium exposed to hypoxic conditions, and that hypoxia induces release of atrial natriuretic peptide from isolated rat atrial tissue. In these studies we suggested that atrial natriuretic peptide may be physiologically important for protection of the myocardium during periods of oxygen deficit. In the present study, we used isolated strips of rat right ventricle, contracted by electrical-field-stimulation, as a model of a beating myocardium. After contraction stabilization, hypoxic conditions were introduced through aeration with 20% O2, held for 20 or 30 min., and then interrupted by reoxygenation with 95% O2. The contractile force was recorded and the percentage regain of the contractions after reoxygenation was considered as an indication of the amount of cell damage induced during the period of hypoxia. The results show that after 30 min. of hypoxia and subsequent reoxygenation, ventricular strips treated with atrial natriuretic peptide (0.1 microM) recovered 67.9 +/- 2.8% of the prehypoxic force of contraction; control strips from the same ventricle regained 44.9 +/- 4.4% (P = 0.015) of their initial contractile activity. After 20 min. of hypoxia followed by reoxygenation, a ventricular strip incubated together with an atrium regained 78.6 +/- 2.4% of the prehypoxic force of contraction as compared to a 60.2 +/- 2.7% regain (P = 0.002) for the control strip. We conclude that atrial natriuretic peptide protects the working ventricular myocardium during hypoxia, which further supports our previously reported suggestion that the effect on myocardial metabolism is physiologically relevant during situations of oxygen deficit in heart muscle.
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Affiliation(s)
- M E Ljusegren
- Department of Pharmacology, Linköping University, Sweden
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23
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Jacobsson LS, Persson K, Aberg G, Andersson RG, Karlberg BE, Olsson AG. Antiatherosclerotic effects of the angiotensin-converting enzyme inhibitors captopril and fosinopril in hypercholesterolemic minipigs. J Cardiovasc Pharmacol 1994; 24:670-7. [PMID: 7528851 DOI: 10.1097/00005344-199410000-00019] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We evaluated the two angiotensin-converting enzyme (ACE) inhibitors captopril and fosinopril with regard to possible antiatherosclerotic effects in minipigs. Experimental hypercholesterolemia and atherosclerosis was produced in 33 minipigs of the Göttingen strain by an egg yolk/cholesterol-enriched diet for 1 year. One group (n = 11) was fed the atherogenic diet alone and served as a control. A second group (n = 11) received captopril (80 mg/kg/day) added to the atherogenic diet, and a third group (n = 11) was treated in the same manner but with fosinopril (8 mg/kg/day). The drug treatments produced significant reduction in serum ACE activity associated with a reactive increase in plasma renin activity (PRA), but had only minor effects on plasma lipids and lipoproteins. At the end of the treatment period, all animals were killed and examined for degree of atherosclerosis. The percentage of atherosclerotic area in the abdominal aorta was significantly lower in both drug-treated groups as compared with controls. Furthermore, accumulation of cholesterol in the thoracic and abdominal aorta was inhibited by drug treatment. Finally, the percentage of intimal thickening in abdominal aorta was significantly reduced in the drug-treated groups. In conclusion, the ACE inhibitors captopril and fosinopril inhibited development of atherosclerosis in hypercholesterolemic minipigs.
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Affiliation(s)
- L S Jacobsson
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden
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24
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Rydberg IG, Andersson RG. Influence of tolfenamic acid on airway contractility in guinea pigs. Pharmacol Toxicol 1994; 75 Suppl 2:33-6. [PMID: 7816777 DOI: 10.1111/j.1600-0773.1994.tb01993.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effect of the NSAIDs tolfenamic acid and indomethacin was tested on acetylcholine-induced and antigen-induced contractions in guinea pig airways. Indomethacin potentiated antigen-induced contractions while tolfenamic acid showed dilatory properties. The effects of the drugs on acetylcholine-induced contractions showed no significant differences; indomethacin had a slightly increasing tendency while tolfenamic acid reduced the contractile response. These results indicate that tolfenamic acid does not have bronchoconstrictive properties, which is a common side effect of other NSAIDs in asthmatics.
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Affiliation(s)
- I G Rydberg
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden
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25
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Ljusegren ME, Andersson RG. Hypoxia induces release of atrial natriuretic peptide in rat atrial tissue: a role for this peptide during low oxygen stress. Naunyn Schmiedebergs Arch Pharmacol 1994; 350:189-93. [PMID: 7990976 DOI: 10.1007/bf00241095] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A variety of different factors have been shown to induce release of atrial natriuretic peptide from atrial tissue. Among these, stretching of atrial myocytes is considered the most important. In a recent study we showed that atrial natriuretic peptide increased cGMP and reduced lactate accumulation during hypoxia in rat ventricular myocardium. This suggests that atrial natriuretic peptide has a beneficial metabolic effect during hypoxia and raises the question whether hypoxia alone induces release of atrial natriuretic peptide. The right atrium and pieces of the right ventricle, from rats, were incubated in polyethylene vials containing 3 ml Krebs bicarbonate buffer equilibrated with 75% N2 + 20% O2 + 5% CO2 (= hypoxic conditions) or 95% O2 + 5% CO2 (= normoxic conditions). After 10 min, the ventricular tissues and aliquots of the buffer were frozen. Cyclic GMP was analyzed in the ventricular tissue and atrial natriuretic peptide was analyzed in the buffer samples. The results show that the release of atrial natriuretic peptide during hypoxia significantly exceeds the release under normoxic conditions. The hypoxia-induced release of atrial natriuretic peptide over time is characterized by an s-shaped curve with the steepest slope after about 10 min. In the presence of atrial tissue the intracellular level of cGMP in ventricular myocardium increased from 0.3 +/- 0.1 to 2.6 +/- 0.9 pmol/g w wt (P = 0.033, n = 6). We conclude that ANP is released from atrial tissue and induces increased formation of cGMP in ventricular myocardium when oxygen tension is low.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M E Ljusegren
- Department of Pharmacology, Linköping University, Sweden
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26
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Abstract
Orally active angiotensin converting enzyme (ACE) inhibitors have been successfully used in the treatment of congestive heart failure and hypertension. However, adverse skin reactions, such as angioneurotic oedema have been reported following such medication. Furthermore, these drugs have been associated with a persistent dry cough in subjects without previous known bronchial hyper-reactivity. There is reason to believe that an ACE inhibitor-induced cough is due to an irritant inflammatory state in the airways of susceptible individuals and that this might have pathophysiological features in common with the cough seen as an early symptom of asthma. All inflammatory responses--wheal and flare reactions, airway reactivity, and infiltration by neutrophils and eosinophils--were enhanced by ACE inhibitors in a dose-dependent manner. Other ACE inhibitors might have different proinflammatory profiles.
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Affiliation(s)
- R G Andersson
- Department of Pharmacology, University Hospital, Linköping, Sweden
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27
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Andersson RG, Jacobsson L, Persson K. Angiotensin converting enzyme inhibitors and atherosclerosis. J Physiol Pharmacol 1994; 45:13-25. [PMID: 8043902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This study was designed to evaluate possible antiatherosclerotic effects of angiotensin converting enzyme inhibitors in mini-pigs. Experimental hypercholesterolemia and atherosclerosis were produced in mini-pigs of the Göttingen strain by adding 11% egg yolk and 1% cholesterol to the diet for 52 weeks. The animals were divided into three groups. One group was fed the atherogenic diet alone and served as control. The second group was treated with captopril in a dose of 80 mg/kg/day added to the atherogenic diet on an individual basis. The third group was treated with fosinopril in a dose of 8 mg/kg/day. Both drugs produced a significant reduction in serum ACE activity associated with a reactive rise in plasma renin activity and a slight fall in serum aldosterone concentration. The drug treatment had only minor effects on plasma lipids. The aorta and the carotid and coronary arteries were examined for atherosclerotic lesions. Atherosclerotic plaques developed in the abdominal aorta whereas fatty streaks were present in the thoracic aorta and the coronary arteries. Both drugs significantly reduced the percent visible atherosclerosis in the abdominal aorta. Furthermore, the accumulation of cholesterol in the thoracic and abdominal aorta was significantly reduced. The effect of captopril and fosinopril on endothelium-dependent relaxation of iliac arteries was examined. After addition of 3 x 10(-7) M acetylcholine strips from basal diet fed mini pigs showed a remaining tension of 7.0% +/- 7.1 (p < 0.05 compared to cholesterol-high diet), cholesterol-high diet 36.4% +/- 10.2, captopril 16.9% +/- 4.9 (p < 0.01) and fosinopril 31.7% +/- 4.6 (n.s.). It is concluded that the ACE inhibitors captopril and fosinopril inhibited the development of atherosclerosis in hypercholesterolemic mini-pigs.
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Affiliation(s)
- R G Andersson
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden
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28
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Abstract
It is suggested that the physiological response caused by an excited membrane-bound receptor can be either local, i.e. localized close to the receptor site, or non-local, spreading over a large volume in the cell. A simple model is presented which shows how locality and non-locality are related to the intrinsic "efficacy" of the drug used in classical receptor theory. It is further demonstrated how the shape of the physiological response versus receptor occupancy is determined by the number of receptor sites which contribute to the physiological response at a given location in the cell.
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Affiliation(s)
- K I Lundström
- Laboratory of Applied Physics, Linköping University, Sweden
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29
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Rosenqvist U, Persson K, Andersson RG. Different proinflammatory profile of three ACE inhibitors: cilazapril, enalaprilat, and ramiprilat. Am J Med 1993; 94:64S-66S. [PMID: 8387723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- U Rosenqvist
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden
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30
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Abstract
Myometrial biopsies from 80 women, delivered by cesarean section in 26-42 completed weeks of pregnancy, were analyzed using radiolabeled alpha 1-antagonist [3H]-prazosin and alpha 2-antagonist [3H]-rauwolscine. Statistical analysis was performed using Student's t test (two-tailed), where p < 0.05 was considered significant. The number of alpha 2-adrenergic receptors did not vary (mean value weeks 37-39 = 17.2 +/- 1.3 fmol/mg protein), while the dissociation constant (Kd) for alpha 2-receptors tended to increase with increasing gestational age, implying reduced affinity near term (p < 0.05, mean values 3.4 +/- 0.2 nM). alpha 1-Receptors, however, increased significantly (p < 0.01) in the pregnancy weeks 37-39 (mean value 29.2 +/- 2.9 fmol/mg prot) while Kd was unaltered. Increased number of alpha 1-receptors, along with a decreased affinity of alpha 2-receptors, could, in combination with other factors, play a role in the initiation of labor.
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Affiliation(s)
- L O Dahle
- Department of Obstetrics and Gynecology, Linköping University, Sweden
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31
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Grundström N, Lindström EG, Andersson RG. Functional aspects of intact airway epithelium: differences between effects induced by antigen or small bioactive molecules. Pharmacol Toxicol 1993; 72 Suppl 3:11-13. [PMID: 7690479 DOI: 10.1111/j.1600-0773.1993.tb01692.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Affiliation(s)
- N Grundström
- Department of Pharmacology, University of Linköping, Sweden
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32
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Lindström EG, Grundström N, Hammarström S, Andersson RG. Relationship between histamine, lipoxygenase and cyclooxygenase products in antigen-induced contraction in guinea-pig tracheal tube preparations. Pharmacol Toxicol 1992; 71:216-20. [PMID: 1438046 DOI: 10.1111/j.1600-0773.1992.tb00549.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have used a tracheal tube preparation to study antigen-induced contraction in sensitized guinea pig airways. Treatment with both the cyclooxygenase inhibitor indomethacin and the lipoxygenase inhibitor MK-886 (L-663,536) affected this contraction in preparations with intact epithelium. Indomethacin potentiated and MK-886 inhibited part of the contraction. Leukotriene release from tracheal tubes was measured after antigen challenge, and was found to be significant in preparations with an intact epithelium. When the epithelium was removed, the histamine receptor antagonist mepyramine reduced antigen-induced contraction by 90%. Our results show that when the epithelium is absent, histamine is the most important mediator in the contraction. With the epithelium left intact, the contraction is more complex: both the cyclooxygenase and lipoxygenase pathways are involved, and our findings indicate that eicosanoid production is associated with the airway epithelium.
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Affiliation(s)
- E G Lindström
- Department of Pharmacology, Faculty of Health Sciences, Linköping, Sweden
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33
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Abstract
The effect of egg albumin (EA) challenge on tracheal tube preparations from sensitized guinea pigs was studied with regard to EA permeability, histamine release and penetrability, and the contractile response of the preparation. We used a plethysmographic method that allowed simultaneous measurement of changes in smooth muscle tension and collection of samples for determination of mediators. Our results clearly show that epithelial damage potentiates the contractile response to histamine, potassium ions, and acetylcholine. Epithelial damage did not alter the maximal contractile response in preparations challenged with high antigen concentrations (EA, 1 mg/ml), but histamine release measured in the perfusate increased substantially. The permeability of the preparations to EA was greater when the epithelium was damaged. No increase in the permeability in response to the EA challenge was observed. The present study has demonstrated that guinea pig airway epithelium constitutes a barrier for both antigen and drugs. We also present a method for recording contractile responses from intact whole tracheal preparations, in which the epithelium can still act as a barrier, as is the case in vivo.
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Affiliation(s)
- N Grundström
- Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden
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34
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Johansson-Rydberg IG, Andersson RG, Grundström N. The modulatory effects of prostaglandins on both excitatory and inhibitory non-adrenergic non-cholinergic neurotransmission in guinea-pig airways. Acta Physiol Scand 1992; 144:439-44. [PMID: 1318635 DOI: 10.1111/j.1748-1716.1992.tb09318.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Guinea-pig trachea and bronchi were used to investigate the effects of indomethacin and prostaglandin E2 (PGE2) on non-adrenergic non-cholinergic excitatory (e-NANC) and inhibitory (i-NANC) neurotransmission evoked by electrical field stimulation. Indomethacin potentiated e-NANC responses in bronchi with intact epithelium but had no effect on epithelium-denuded preparations. Inhibitory NANC responses were increased by indomethacin independent of the epithelium. Both i-NANC and e-NANC neurotransmission were suppressed by PGE2 in a dose-dependent manner. These results indicate that endogenous prostaglandins (e.g. PGE2) generated from the epithelium have an inhibitory effect on i-NANC and e-NANC nerve responses in airways. The epithelium is presumably not the only source for generation of prostaglandins that are involved in i-NANC neurotransmission.
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Affiliation(s)
- I G Johansson-Rydberg
- Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden
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35
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Abstract
Microdialysis, a new bioanalytical sampling technique, enables the measurement of substances in the extracellular space. This study investigates the use of the technique in the in vivo measurement of histamine levels in human skin. Microdialysis probes are equipped at the tip with a semipermeable polycarbonate membrane which permits the passive diffusion of substances. 16 probes were inserted, via a guide, into the skin of the ventral forearm of 8 patients or volunteers. The probe was perfused at a flow of 5 microliters/min, with samples being collected at intervals of 10 min and analysed by RIA technique. The mean histamine level in the first 10-min sample following probe insertion was 39.4 nM. The mean histamine value fell with successive 10-min samples (8.8, 4.6, 2.3 nM). An equilibration period of 40 min following probe insertion is suggested for histamine studies, where provocation of the skin is to be performed. Microdialysis appears to be a promising new tool for quantitative and chronological studies of cutaneous inflammatory mediators.
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Affiliation(s)
- C Anderson
- Department of Dermatology, University Hospital, Linköping, Sweden
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36
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Svensson SP, Andersson RG, Karlsson JO. Reciprocal changes in sensitivity to MCH and noradrenaline after denervation of teleost melanophores. Pigment Cell Res 1991; 4:252-4. [PMID: 1823930 DOI: 10.1111/j.1600-0749.1991.tb00449.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Melanophores of isolated fish scales survive for weeks in a culture medium. During this isolation period a progressive increase in sensitivity to noradrenaline (NA) takes place. In the present study, a 100-fold increase in sensitivity to NA was found after 9 days. However, at the same time, a 12-fold decrease in sensitivity to MCH was detected.
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Affiliation(s)
- S P Svensson
- Department of Pharmacology, University of Linköping, Sweden
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37
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Ahlner J, Andersson RG, Torfgård K, Axelsson KL. Organic nitrate esters: clinical use and mechanisms of actions. Pharmacol Rev 1991; 43:351-423. [PMID: 1956955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- J Ahlner
- Department of Clinical Pharmacology, Faculty of Health Sciences, University Hospital, Linköping, Sweden
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38
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Karlsson JO, Andersson RG, Askelöf P, Elwing H, Granström M, Grundström N, Lundström I, Ohman L. The melanophore aggregating response of isolated fish scales: a very rapid and sensitive diagnosis of whooping cough. FEMS Microbiol Lett 1991; 66:169-75. [PMID: 1936946 DOI: 10.1111/j.1574-6968.1991.tb04860.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pertussis toxin (PT) has been found to block noradrenaline-induced pigment aggregation in fish melanophores, and, based on this, a rapid and highly sensitive assay for PT was developed. Some preliminary results have also indicated that it may be possible to detect PT-like activity in saliva samples from patients with clinically suspected pertussis. In the present study the diagnostic value of the fish melanophore method was evaluated in 70 patients suspected of having pertussis; culture, serology and physician diagnosis were used as reference methods. In 60 of the patients, pertussis was verified by at least one of the reference methods. The melanophore test showed PT-like activity in saliva samples from 58 of the patients. Three patients with reference-verified pertussis showed no PT-like activity in the test; among these, one patient had been immunized and had also been treated with erythromycin during 3 days immediately prior to visiting the hospital. The melanophore test has three major advantages: it allows detection of pertussis in the early and curable stage of the disease; it takes only 2 h to perform; and it requires no sophisticated equipment.
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Affiliation(s)
- J O Karlsson
- Department of Pharmacology, Linköping University, Regionsjukhuset, Sweden
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39
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Svensson SP, Mårtensson LG, Grundström N, Andersson RG, Cragoe EJ, Karlsson JO. Antagonistic effect of amiloride on alpha-2 adrenoceptor-mediated pigment aggregation: pharmacological heterogeneity between B-HT 920 and noradrenaline. J Pharmacol Exp Ther 1991; 258:447-51. [PMID: 1678012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Pigment aggregation in melanophores from the cuckoo wrasse (Labrus ossifagus L.) has previously been shown to be mediated by alpha-2 adrenoceptors. In the present investigation, the effect of amiloride on pigment aggregation induced by noradrenaline and B-HT 920 was studied. Amiloride caused a parallel shift to the right in concentration-response curves for 5-allyl-2-amino-5,6,7,8-tetrahydrothiazolo-[4,5-d]azepine-dihyd roc hloride: (B-HT 920), with no change in the maximal response, indicating simple competitive inhibition. Subsequent Schild plot analysis gave a straight line with a slope of almost unity (0.95) and a KB of 5 x 10(-6) M. In contrast to the effect of amiloride on B-HT 920-induced pigment aggregation, only a very high concentration of amiloride (1 x 10(3) M) inhibited the corresponding effect of noradrenaline. Na+/H+ exchange has been suggested as a possible mechanism for alpha-2 adrenoceptors, and the amiloride analogs 5-(N,N-dimethyl)amiloride and 5-(N,N-hexamethylene)amiloride are known to be more specific than amiloride itself in this respect. However, these analogs inhibited the effect of B-HT 920 significantly less effectively than amiloride. Furthermore, manipulating the extracellular pH between 6.8 and 7.8 did not affect the concentration response curves of B-HT 920. Neither did the prostanoid pathway inhibitors, quinacrine or indomethacin, inhibit the pigment-aggregating effect of B-HT 920. The present results suggest that amiloride competes with B-HT 920 as receptor antagonist, and that Na+/H+ exchange is insignificant for the alpha-2 adrenoceptor-stimulated pigment aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S P Svensson
- Department of Pharmacology, Linköping University, Sweden
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40
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Abstract
ACE-inhibitors have for some time been used in the treatment of hypertension. Apart from inhibiting the conversion of angiotensin I to II, the drugs also affect the metabolism of some inflammatory agents, like bradykinin and substance P. Egg albumin (EA)-sensitized guinea pigs were pretreated with the ACE-inhibitors. Measurement of flare and wheal areas induced by an intradermal injection of EA, showed that enalaprilat significantly increased, whereas cilazaprilat slightly decreased, the reaction area. Enalaprilat also showed an enhancement in histamine and substance P (SP) contents in the skin. In vitro incubation of guinea pig biopsies with enalaprilat potentiated EA- but not SP-induced histamine release. The EA-induced effect was abolished if the animals were pretreated with capsaicin. The conclusion is that cilazaprilat, in contrast to enalaprilat, does not potentiate inflammatory reactions in the guinea pig.
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Affiliation(s)
- K M Persson
- Dept. of Pharmacology, University of Linköping, Sweden
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41
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Jacobsson L, Grundström N, Andersson RG. Influence of some alpha 2-receptor agonists and antagonists on the excitatory non-adrenergic, non-cholinergic neurotransmission in the airways of guinea-pigs in vivo. Acta Physiol Scand 1991; 142:91-6. [PMID: 1678910 DOI: 10.1111/j.1748-1716.1991.tb09132.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Neural control of smooth muscle tension in the airways of guinea-pigs can be subdivided into at least four components: an excitatory cholinergic, an inhibitory noradrenergic, an excitatory non-adrenergic, non-cholinergic and an inhibitory non-adrenergic, non-cholinergic component. The existence of alpha 2-adrenoceptors that modulate the excitatory non-adrenergic, non-cholinergic nerve activity has also been demonstrated. The aim of the present study was to investigate the dose-dependence of the selective alpha 2-receptor agonists UK 14,304, dexmedetomidine and clonidine on these alpha 2-adrenoceptors in the airway of guinea-pigs in vivo. Electrical stimulation of the cervical vagus nerves in anaesthetized guinea-pigs resulted in a biphasic response in insufflation pressure: an immediate increase due to excitation of cholinergic nerve fibres and a slower, longer-lasting increase due to activation of the excitatory non-adrenergic, non-cholinergic fibres to be studied. The cholinergic compound was abolished by atropine, leaving the excitatory non-adrenergic, non-cholinergic component as the sole response recorded during vagal stimulation. UK 14,304 and dexmedetomidine attenuated the response in a dose-dependent manner, whereas the effect of the partial agonist clonidine was less dose-related. UK 14,304 and dexmedetomidine reduced the insufflation pressure about 60 and 53% respectively at the highest dose. In conclusion, the neurotransmission in the excitatory non-adrenergic, non-cholinergic nerves is attenuated by selective alpha 2-receptors in a dose-dependent manner. The present study adds support to earlier observations that the excitatory non-adrenergic, non-cholinergic neural system in the airways of guinea-pigs is modulated by alpha 2-adrenoceptors.
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Affiliation(s)
- L Jacobsson
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden
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42
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Lindström EG, Andersson RG, Granérus G, Grundström N. Is the airway epithelium responsible for histamine metabolism in the trachea of guinea pigs? Agents Actions 1991; 33:170-2. [PMID: 1910251 DOI: 10.1007/bf01993158] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The aim of the study was to investigate whether or not the epithelium plays an active role in histamine metabolism, via the histaminase and/or methyltransferase pathways. Isolated tracheas from guinea pigs sensitized to egg albumin (EA) were used. The epithelium was either left intact or removed from the preparations. The tracheal tubes were mounted in a chamber, allowing estimation of smooth muscle tension, and perfused with buffer. In some experiments the perfusate was collected for determination of histamine and methylhistamine. Mepyramine was used to evaluate the contribution of histamine to the EA-induced contraction. Mepyramine reduced the contraction by 90% when the epithelium was removed; with intact epithelium the reduction was 47%. Aminoguanidine, a histaminase inhibitor, significantly potentiated the response to EA when the epithelium was left intact. Traces of methylhistamine were detected in tissue extracts and perfusates. We conclude that histaminase is present in the preparation and that it can contribute to the inhibitory effect of the epithelium by means of histamine degradation.
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Affiliation(s)
- E G Lindström
- Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden
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43
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Abstract
Two non-sulfur containing ACE-inhibitors were tested concerning their local effect on experimental dermatitis in ovalbumin-sensitized guinea pigs. Enalaprilat but not cilazaprilat potentiated the ovalbumin-evoked inflammatory response. Furthermore, enalaprilat clearly enhanced the erythema evoked by substance P, whereas cilazaprilat did not. Concerning, the bradykinin-evoked erythema, enalaprilat significantly potentiated the response, whereas cilazaprilat only caused a slight increase. Our results suggest that different affinities for peptidases involved in degradation of inflammatory peptides can explain differences between the pro-inflammatory properties of enalaprilat and cilazaprilat.
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Affiliation(s)
- U Rosenqvist
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden
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44
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Abstract
The inflammatory effects of enalaprilat and cilazaprilat were tested in an experimental model of ovalbumin-sensitised guinea-pigs. Enalaprilat, but not cilazaprilat, enhanced the ovalbumin-induced inflammatory skin responses. The effect of enalaprilat was dose-dependent. Enalaprilat significantly increased the skin content of substance P and histamine. Cilazaprilat did not alter the level of these inflammatory mediators. Enalaprilat, applied locally, but not cilazaprilat, enhanced the inflammatory reactions caused by intradermal injections of allergen and substance P. Both angiotensin converting enzyme (ACE) inhibitors enhanced the inflammatory skin response evoked by bradykinin. Our study strongly indicates that enalaprilat has pro-inflammatory properties, whereas the new long-acting ACE inhibitor cilazaprilat does not. This might give a better safety profile of cilazaprilat.
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Affiliation(s)
- R G Andersson
- Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden
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45
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Svensson SP, Norberg T, Andersson RG, Grundström N, Karlsson JO. MCH-induced pigment aggregation in teleost melanophores is associated with a cAMP reduction. Life Sci 1991; 48:2043-6. [PMID: 1851917 DOI: 10.1016/0024-3205(91)90160-d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
It has previously been shown that alpha 2-adrenoceptors are involved in noradrenaline-induced pigment aggregation within fish melanophores. In the present investigation, melanin concentrating hormone (MCH) elicited pigment aggregation (EC50 approximately 1 x 10(-7) M) that was associated with a significant reduction in the cAMP content; 1 x 10(-7) M MCH reduced the cAMP content from a basal level of 50.4 +/- 2.8 pmol/mg protein to 36.9 +/- 3.8 pmol/mg protein. Like the alpha 2-adrenoceptor-induced pigment aggregation, the MCH response was effectively blocked by the adenylate cyclase stimulator forskolin. These findings suggest that attenuation of cAMP may serve as an intracellular signal transduction mechanism for both MCH and noradrenaline.
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Affiliation(s)
- S P Svensson
- Department of Pharmacology, University of Linköping, Sweden
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46
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Wigilius IM, Axelsson KL, Andersson RG, Karlsson JO, Odman S. Effects of sodium nitrite on ultraviolet light-induced relaxation and ultraviolet light-dependent activation of guanylate cyclase in bovine mesenteric arteries. Biochem Biophys Res Commun 1990; 169:129-35. [PMID: 1972015 DOI: 10.1016/0006-291x(90)91443-v] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
It was demonstrated that precontracted strips from different bovine mesenteric arteries showed variation in sensitivity to ultraviolet radiation (366 nm). Some strips relaxed when they were exposed to ultraviolet light, others showed no sensitivity at all and, finally, some showed contraction. However, all arteries relaxed when they were irradiated with UV-light in the presence of 10 microM NaNO2. Ultraviolet radiation (366 nm) increased the activity of guanylate cyclase in crude homogenate from bovine mesenteric arteries by about 20-fold in the presence of NaNO2, while UV-light in the absence of sodium nitrite had no effect on the guanylate cyclase activation. These results support the notion that nitrite may be essential for vascular smooth muscle relaxation by UV-light, possibly through the release of nitric oxide.
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Affiliation(s)
- I M Wigilius
- Department of Pharmacology, Linköping University, Sweden
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47
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Ahlner J, Axelsson KL, Karczewski P, Andersson RG. Studies of the effect of glyceryl trinitrate and cyclic GMP on calcium turnover in bovine mesenteric artery. Pharmacol Toxicol 1990; 66:277-82. [PMID: 2164665 DOI: 10.1111/j.1600-0773.1990.tb00747.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It was recently observed that the relaxation induced by glyceryl trinitrate (GTN) showed a biphasic concentration-response curve; a high-sensitivity component represented by concentrations less than 1 nM and a low-sensitivity component represented by concentrations greater than 1 nM. The effect of two glyceryl trinitrate concentrations (0.1 nM and 1 microM) were tested on the uptake of 45Ca2+ to tissue pieces of bovine mesenteric arteries (BMA) as well as on the uptake of 45Ca2+ to a microsomal preparation of BMA. The effect of GTN and 8-Br-cGMP was also studied on the IP3-induced release of Ca2+ from the microsomal preparation preloaded with 45Ca2+. The influence of IP3 and GTN on the activity of Ca2(+)-ATPase in the microsomal preparation was tested as well. The phenylephrine-stimulated uptake of Ca2+ to tissue pieces of BMA was significantly reduced by the high GTN-concentration (1 microM) but not by the lower concentration. The uptake of Ca2+ to the microsomal preparation was significantly stimulated by the two GTN-concentrations tested, as well as by 8-Br-cGMP (0.1 mM). The calcium release induced by IP3 (1 microM) from the microsomal preparation was inhibited by both the low and the high GTN-concentration and by 8-Br-cGMP (0.1 mM). The Ca2(+)-ATPase activity was stimulated by both GTN-concentrations tested while it was inhibited by IP3. It is concluded that GTN is able to induce a reduction of the free intracellular Ca2+ by several mechanisms, which are of importance for the relaxation represented by the high-affinity component. The low-affinity component in addition reduces the inflow of Ca2+ over the plasma membrane.
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Affiliation(s)
- J Ahlner
- Department of Clinical Pharmacology, University Hospital, Linköping, Sweden
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48
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Grundström N, Lindström EG, Andersson RG. Can the epithelium affect allergen-evoked histamine release from the perfused guinea pig trachea? Agents Actions 1990; 30:118-20. [PMID: 1695427 DOI: 10.1007/bf01969014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The aim of this study was to investigate the influence of the epithelium on allergen-evoked histamine release. Isolated tracheal preparations from guinea-pigs, with the epithelium either left intact or removed, were used. The trachea was perfused and challenged with egg-albumin (EA) either extra- or intraluminally. Fractions of the perfusate were collected for analysis of the histamine and EA contents. When EA was added intraluminally and the epithelium was removed, a marked peak in histamine release could be detected. In the presence of intact epithelium there was no marked histamine peak. EA added extraluminally gave the same results but the histamine peak was less pronounced. The epithelium apparently acts as a barrier, the nature of which remains to be elucidated.
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Affiliation(s)
- N Grundström
- Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden
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49
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Grundemar L, Grundström N, Johansson IG, Andersson RG, Håkanson R. Suppression by neuropeptide Y of capsaicin-sensitive sensory nerve-mediated contraction in guinea-pig airways. Br J Pharmacol 1990; 99:473-6. [PMID: 1691946 PMCID: PMC1917333 DOI: 10.1111/j.1476-5381.1990.tb12952.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
1. In the present study we have examined whether neuropeptide Y (NPY) interferes with non-adrenergic, non-cholinergic nerve-mediated contractions and relaxations in the guinea-pig airways. In these experiments we have used ring preparations of bronchi and trachea, incubated in the presence of atropine, propranolol and indomethacin (each 1 microM). 2. The contractile response to electrical stimulation of non-adrenergic, non-cholinergic nerve fibres was suppressed by NPY and NPY 13-36 in a concentration-dependent manner, these agents having similar inhibitory potencies. NPY caused a more complete inhibition than the C terminal fragment. 3. NPY affected neither the basal tension nor the substance P-evoked contraction in the bronchi and trachea and did not interfere with nerve-mediated, non-adrenergic relaxation in the trachea. 4. On the basis of these results, it is suggested that NPY may act on the terminals of sensory neurones in the airways to prevent antidromic, excitatory neurotransmission by inhibiting transmitter release.
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Affiliation(s)
- L Grundemar
- Department of Pharmacology, University of Lund, Sweden
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50
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Ljusegren ME, Axelsson KL, Ahlner J, Karlsson JO, Andersson RG, Magnusson BR, Friedman RL. Effects of pertussis toxin on vasodilation and cyclic GMP in bovine mesenteric arteries and demonstration of a 40 kD soluble protein ribosylation substrate for pertussis toxin. Life Sci 1990; 46:543-52. [PMID: 2155364 DOI: 10.1016/0024-3205(90)90121-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The inhibitory nucleotide-regulatory protein (Gl) has been shown to lose its adenylate cyclase inhibitory effect upon treatment with pertussis toxin. To find out whether a pertussis sensitive mechanism is involved in the regulation of the cGMP-system, bovine mesenteric arteries were incubated in buffer containing pertussis toxin, and the relaxation and intracellular cGMP accumulation induced by different groups of vasodilating agents were studied. The present results show a pertussis toxin induced decrease in relaxation as well as a decrease in the cGMP-elevation induced by the endothelium dependent vasodilators acetylcholine and calcium ionophore A 23187. Arteries treated with atrial natriuretic peptide showed no alterations in relaxation or cGMP content after incubation with pertussis toxin. A 40 kD soluble ribosylation substrate for pertussis toxin was identified in bovine mesenteric artery. These results suggest that a pertussis toxin sensitive mechanism is involved in the vasodilating mechanism of acetylcholine and calcium ionophore A 23187, while no evidence for such a mechanism could be found regarding the vasodilatory action of atrial natriuretic peptide.
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