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- Konrad, D, et al.
(författare)
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Positive inotropic and negative lusitropic effects of endothelin receptor agonism in vivo.
- 2005
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Ingår i: Am J Physiol Heart Circ Physiol. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 289:4
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Tidskriftsartikel (refereegranskat)abstract
- The endothelin (ET) system is involved in the regulation of myocardial function in health as well as in several diseases, such as congestive heart failure, myocardial infarction, and septic myocardial depression. Conflicting results have been reported regarding the acute contractile properties of ET-1. We therefore investigated the effects of intracoronary infusions of ET-1 and of the selective ET(B) receptor-selective agonist sarafotoxin 6c with increasing doses in anesthetized pigs. Myocardial effects were measured through analysis of the left ventricular pressure-volume relationship. ET-1 elicited increases in the myocardial contractile status (end-systolic elastance value of 0.94 +/- 0.11 to 1.48 +/- 0.23 and preload recruitable stroke work value of 68.7 +/- 4.7 to 83.4 +/- 7.2) that appear to be mediated through ET(A) receptors, whereas impairment in left ventricular isovolumic relaxation (tau = 41.5 +/- 1.4 to 58.1 +/- 5.0 and t(1/2) = 23.0 +/- 0.7 to 30.9 +/- 2.6, where tau is the time constant for pressure decay and t(1/2) is the half-time for pressure decay) was ET(B) receptor dependent. In addition, intravenous administration of ET-1 impaired ventricular relaxation but had no effect on contractility. Intracoronary sarafotoxin 6c administration caused impairments in left ventricular relaxation (tau from 43.3 +/- 1.8 to 54.4 +/- 3.4) as well as coronary vasoconstriction. In conclusion, ET-1 elicits positive inotropic and negative lusitropic myocardial effects in a pig model, possibly resulting from ET(A) and ET(B) receptor activation, respectively.
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- Wang, Jianpu, 1957-, et al.
(författare)
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Effects of endothelin receptor antagonism on acute lung injury induced by chlorine gas
- 2006
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Ingår i: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 34:6, s. 1731-1737
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To test the hypothesis that the endothelin system is involved in chlorine gas-induced lung injury.DESIGN: Experimental study.SETTING: Academic research laboratory.SUBJECTS: Twenty-four domestic juvenile pigs.INTERVENTIONS: Anesthetized, ventilated pigs were exposed to chlorine gas (400 parts per million in air) for 20 mins and then randomly allocated to four groups (n = 6 in each group). The tezosentan pretreatment group received the dual endothelin receptor antagonist tezosentan 20 mins before and hyperoxic gas (Fio2 0.6) after chlorine gas exposure. The tezosentan postinjury treatment group received hyperoxic gas after chlorine gas exposure and tezosentan 60 mins later. Animals in the oxygen group received hyperoxic gas after chlorine gas exposure. Pigs in the fourth group (air) were ventilated with room air (Fio2 0.21) throughout the experiment.MEASUREMENTS AND MAIN RESULTS: Hemodynamics, gas exchange, lung mechanics, and plasma endothelin-1 were evaluated for 6 hrs. Chlorine gas exposure induced an increase in circulating endothelin-1 by 90% (p < .05). The acute chlorine gas-induced rise in pulmonary vascular resistance was partly blocked by tezosentan pretreatment (p < .001). Tezosentan postinjury treatment also decreased pulmonary vascular resistance to levels significantly lower than in the air and oxygen groups (p < .001). Recovery of peak airway pressure was better in the tezosentan-treated groups than in the air group. There were significant linear relationships between circulating endothelin-1 and pulmonary vascular resistance (r = .47, p < .001) and endothelin-1 and peak airway pressure (r = .41, p < .001). These relationships were modified by tezosentan.CONCLUSIONS: Tezosentan modified chlorine gas-induced pulmonary dysfunction, indicating that the endothelin system is involved in this mode of acute lung injury.
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