Search results for " Adrenergic"

Biochemical interaction between effects of beclomethasone dipropionate and salbutamol or formoterol in sputum cells from mild to moderate asthmatics.

2005

Background:  Several in vitro studies demonstrate that corticosteroids and long-acting β2 agonists may have a complementary and synergistic mode of action on the inflammatory processes in asthma. Methods:  Sputum was induced in 20 mild to moderate asthmatic patients and the induced sputum cells (ISC) were cultured with beclomethasone dipropionate (BDP) 10−7 M, salbutamol 10−8 M and formoterol 10−8 M either alone or in combination, BDP plus salbutamol and BDP plus formoterol, for 24 h. We measured the levels of growth macrophages-colony stimulating factor (GM-CSF), released on activation normal T cells expressed and activated (RANTES) and interleukin-8 (IL-8), in the supernatant of stimulate…

Effects of β-adrenergic blockade on EMG signal characteristics during progressive exercise

1984

Myocardial and Peripheral Lymphocytic Transcriptomic Dissociation of β-adrenoceptors and G Protein–coupled Receptor Kinases in Heart Transplantation

2009

Background The genetic expression of adrenergic receptors plays an important pathophysiologic role in heart failure. G protein–coupled receptor kinases (GRKs) desensitize the β-receptor to catecholaminergic stimulation. It has been suggested that their mRNA expression in peripheral lymphocytes could mirror the changes in their myocardial expression in the failing heart, but this relationship between the myocyte and lymphocyte has not been studied in heart transplantation (HT). The objective of this study was to analyze adrenergic receptor and GRK mRNA expression in myocardium and lymphocytes and their correlation. Methods Twenty-three HT patients without evidence of acute rejection or echoc…

Autonomic regulation of nasal vessels during changes in body position

1994

The effects of postural changes on nasal airflow and nasal capillary blood flow were investigated in 15 healthy volunteers. Measurements were performed following nasal application of saline solution (control), the alpha-1 receptor antagonist prazosin, the alpha-2 receptor antagonist yohimbine, and after application of both prazosin and yohimbine. Nasal airflow in the control experiments did not significantly differ in the upright (362 +/- 166 ml/s), dorsally recumbent (350 +/- 167 ml/s) and 70 degrees head down position (311 +/- 167 ml/s). Following application of prazosin, nasal airflow was reduced to 223 +/- 121 ml/s in the upright position. Prazosin treatment significantly reduced nasal …

Sympathetic nervous activity and the pressor effect of noradrenaline under chronic?-?-adrenoceptor blockade with labetalol in hypertension

1983

In 14 patients with essential hypertension, the influence of the alpha- and beta-adrenoceptor blocking drug labetalol on blood pressure, heart rate, plasma renin, plasma noradrenaline and pressor effect of exogenous noradrenaline was investigated during long-term treatment. During the initial four weeks of treatment, labetalol at a dose of 400 mg/day showed a slight effect only on supine blood pressure, whereas upright blood pressure was already lowered effectively after the second week of treatment (p less than 0.01). An increase in the mean dose to 850 mg/day had an additional blood pressure-lowering effect (p less than 0.001), whereby a preferential decrease of the orthostatic blood pres…

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…

Desensitization of inhibitory prejunctional alpha 2-adrenoceptors and putative imidazoline receptors on rabbit heart sympathetic nerves.

1993

To find out whether sympathetic nerves of the rabbit heart possess pharmacologically relevant prejunctional imidazoline receptors different from α-autoreceptors, the inhibition by oxymetazoline, aganodine and BDF 6143 (4-chloro-2-[2-imidazoline-2-ylamino]-isoindoline hydrochloride) of endogenous noradrenaline overflow evoked by stimulation of extrinsic postganglionic sympathetic nerves (0.66 Hz, 80 pulses) was investigated. In addition we wanted to find out whether either type of these prejunctional receptors undergoes desensitization upon pre-exposure to respective agonists. The α2-adrenoceptor agonist oxymetazoline inhibited the evoked noradrenaline overflow (2.9 nmol/l, IC50; about 90010…

Characterization of sensory neurotransmission and its inhibition via alpha 2B-adrenoceptors and via non-alpha 2-receptors in rabbit iris.

1993

To find out whether, and which type of, adrenoceptors mediate prejunctional inhibition of sensory neurotransmitter release from trigeminal fibres, the modulation of twitch response to electrical field stimulation on rabbit isolated iris was investigated. Evoked iris sphincter contractions consisted of a minor fast cholinergic and a large slow component. The latter was unaffected by atropine and guanethidine, hence nonadrenergic noncholinergic in nature (NANC), but nearly completely abolished by capsaicin pretreatment and by the neurokinin receptor antagonist spantide. The response was probably not mediated by NK2 receptors as SR 48,968, an NK2 selective nonpeptide antagonist, failed to redu…

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…

Opposite vascular activity of (R)-apomorphine and its oxidised derivatives. Endothelium-dependent vasoconstriction induced by the auto-oxidation meta…

2003

We have synthetised a series of oxidised apomorphine derivatives (orto and para quinones 2-5), in order to analyse their vascular activity. We have performed radioligand binding assays on rat cortical membranes and functional studies on rat aortic rings. Instead the relaxant activity exhibited by (R)-apomorphine, o-quinones 2, 4, show contractile activity dependent on endothelium in rat aortic rings. Compound 2, the main metabolite of (R)-apomorphine auto-oxidation, was the product which showed enhanced contractile activity by a complex mechanism related to activation of Ca(2+) channels through release and/or inhibition of endothelial factors. Moreover, this compound disrupts the endothelia…