Search results for "isoprenaline"
showing 10 items of 48 documents
Desensitization of cAMP Accumulation via Human β3-Adrenoceptors Expressed in Human Embryonic Kidney Cells by Full, Partial, and Biased Agonists
2019
β3-Adrenoceptors couple not only to cAMP formation but, at least in some cell types, also to alternative signaling pathways such as phosphorylation of extracellular signal-regulated kinase (ERK). β3-Adrenoceptor agonists are used in long-term symptomatic treatment of the overactive bladder syndrome; it is only poorly understood which signaling pathway mediates the clinical response and whether it undergoes agonist-induced desensitization. Therefore, we used human embryonic kidney cells stably transfected with human β3-adrenoceptors to compare coupling of ligands with various degrees of efficacy, including biased agonists, to cAMP formation and ERK phosphorylation, particularly regarding des…
beta-Adrenoceptor-mediated Relaxation of Urinary Bladder Muscle in beta 2-Adrenoceptor Knockout Mice
2016
Background and Objective. In order to characterize the β-adrenoceptor (AR) subtypes involved in agonist-stimulated relaxation of murine urinary bladder we studied the effects of (-)-isoprenaline and CL 316,243 on tonic contraction and spontaneous contractions in detrusor strips of wild-type (WT) and β2-AR knockout (β2-AR KO) mice. Materials and Methods. Urinary bladders were isolated from male WT and β2-AR KO mice. β-AR subtype expression was determined with quantitative real-time PCR. Intact muscle strips pre-contracted with KCl (40 mM) were exposed to cumulatively increasing concentrations of (-)-isoprenaline or β3-AR agonist CL 316,243 in the presence and absence of the subtype-selective…
Positive inotropic response to 5-HT in human atrial but not in ventricular heart muscle
1992
The effects of 5-hydroxytryptamine (5-HT) on force of contraction (FC), action potential (AP) and calcium current (ICa) were studied in human right atrial and left ventricular heart muscle. 5-HT exerted a concentration-dependent increase in FC in multicellular atrial preparations; the EC50 was approximately 3 x 10(-7) mol/l. Maximal increases in FC (252 +/- 58% of control values; mean +/- SEM, n = 6) were obtained at 5-HT 10(-5) mol/l. At this concentration, ICa was increased four- to sevenfold in enzymatically isolated atrial myocytes. In contrast, ventricular preparations did not respond to 5-HT; FC, AP and ICa remained unaffected. In the same preparations, FC was increased by isoprenalin…
Functional, biochemical and morphological studies on human bronchi after cryopreservation
1995
1. Human isolated bronchi have been investigated as fresh tissue or after storage (7 and 30 days) at -196 degrees C in foetal calf serum containing 1.8 M dimethyl sulphoxide. 2. After cryopreservation, the maximal contractile response to acetylcholine (3 mM) was reduced (approximately 25%) but the difference did not reach significance statistically. Maximal responses to other spasmogens tested (histamine, [Nle10]NKA(4-10), bradykinin, leukotriene D4, U46619, and KCl) did not differ between unfrozen and frozen/thawed tissues. The sensitivity of cryopreserved tissues to the constrictor agents tested was similar to that of fresh tissues. 3. The accumulation of inositol phosphates produced by a…
Beta-adrenergic stimulation enhances left ventricular diastolic performance in normal subjects.
1997
To determine the effects of beta-adrenergic stimulation on transmitral Doppler echocardiography flow characteristics of left ventricular diastolic filling, we studied 10 healthy volunteers aged 23-31 years (mean age, 26.6 years) during intravenous infusion of isoprenaline in consecutive steps of 0.1, 0.2, 0.4, 0.75, and 1.5 micrograms/min (each for 15 min). Saline control infusion was given in the same manner in a crossover and blinded protocol. Compared with the infusion of placebo, stepwise increasing doses of isoprenaline caused a dose-related increase in early and late diastolic filling velocities and velocity-time integrals, a lengthening of the acceleration time, and a shortening of t…
Relative sensitivity of four noninvasive methods in assessing systolic cardiovascular effects of isoproterenol in healthy volunteers.
1992
Study objective The study was performed to evaluate the relative sensitivity of various noninvasive methods to detect and describe the systolic cardiovascular effects of stepwise increasing doses of isoproterenol: two-dimensional left ventricular echocardiography (main variable, ejection fraction), ACVF (attenuation compensated volume flow)–dual-beam Doppler echoaortography (time-averaged mean velocity), electrical impedance cardiography [(dZ/dtmax)/RZ index], and systolic time intervals from mechanocar-diography (PEP and QS2c). Methods Isoproterenol was administered by constant rate intravenous infusion in consecutive steps of 0.1, 0.2, 0.4, 0.75, and 1.5 µg/min (each for 15 minutes). Sali…
Investigation into isoprenaline resistance in patients with obstructive lung disease
1974
12 patients with chronic obstructive lung disease have been studied in an investigation regarding the causes of resistance to isoprenaline. The effects of repeated intravenous doses of 10 µg isoprenaline were assessed by cross over comparison before and after infusions of isoprenaline and a placebo; the infusions lasted for 35 to 40 min and the amount of isoprenaline infused was 0.5 µg/min. Total resistance, thoracic gas volume (whole-body plethysmography) and heart rate (ECG) were measured. No decrease in bronchospasmolytic or positive chronotopic effects on single isoprenaline injections could be demonstrated after prolonged infusions of isoprenaline.
0149: Agonistic anti β3-adrenoceptor antibodies do not affect the β1-adrenoceptor-mediated inotropy and the β3 adrenoceptor-mediated vasorelaxation i…
2014
Cardiac activity of autoantibodies (AABs) directed against β1-adrenoceptor (β1-AR) has been proposed to play an important role in the pathogenesis of dilated cardiomyopathy. Our previous work has shown that the immunization of rats with the second extracellular loop (ECII) of β1-AR induced endothelial dysfunction in aorta and mesenteric arteries. However, until now, no study has explored the cardiovascular effects of β3-AABs alone or combined with β1-AABs.AimTo evaluate whether β3-AABs possess β3-AR agonistic effect and whether active immunization producing β3-AABs and/or β1-AABs has deleterious effects on cardiac and vascular reactivity in Lewis rats.MethodsLewis rats were immunized for 3 …
A study of beta-adrenoceptors in rat lung parenchymal strip.
1989
Abstract The aim of the present study was to characterize the β-adrenoceptor population in rat lung strip. For this purpose, Schild plots were obtained for the β-adrenoceptor antagonists atenolol (β1-selective), butoxamine (β2-selective) and propranolol (nonselective), using three different agonists: isoprenaline (non-selective), salbutamol (β2-selective) and noradrenaline (β11-selective). The slopes of these Schild plots were close to the theoretical value of unity, and pA2 values determined with isoprenaline, salbutamol and noradrenaline as agonists were: for propranolol, 7·86 ± 0·22, 7·72 ± 0·15 and 7·89 ± 0·23; for atenolol, 5·19 ± 0·05, 5·33 ± 0·07 and 5·47 ± 0·22 and for butoxamine, 6…
Changes in Adrenoceptors and G-Protein-Coupled Receptor Kinase 2 in <smlcap>L</smlcap>-NAME-Induced Hypertension Compared to Spontaneous …
2014
This work compares the expression of adrenoceptors (ARs) and G-protein-coupled receptor kinase (GRK) 2 (RT-PCR and immunoblotting) and functional responses in conductance (aorta) and resistance vessels (mesenteric resistance arteries; MRA) in two different models of rat hypertension: hypertension induced by chronic treatment with <smlcap>L</smlcap>-NAME (N<sup>G</sup>-nitro-<smlcap>L</smlcap>-arginine methyl-ester) (<smlcap>L</smlcap>-NAME-treated rats; LNHR), and genetically induced hypertension (spontaneously hypertensive rats; SHR). Changes found in the aorta, but not in the MRA, were: (1) a loss of contractile capacity, more evidently in α…