Effect of clenbuterol on beta‐adrenoceptors and adenylate cyclase activity in smooth muscle and epithelium of the trachea of calves

Roets, E; Burvenich, Christian

doi:10.1080/01652176.1993.9694402

Cited by 3 publications

(3 citation statements)

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“…An important down-regulation of fl-adrenoceptors in the lung tissue of adults is thus accompanied by an unchanged ability to produce cAMP. Similar results were found after administration of the fl-agonist clenbnterol to young calves (Roets and Burvenich, 1993). As NaF exerts its activity through interaction with the Gs-protein, these results suggest that there may be an alteration in the functional coupling of Gs-proteins with the catalytic units of AC.…”

Section: Discussionsupporting

confidence: 84%

The influence of ageing on muscarinic receptors, β-adrenoceptors and adenylate cyclase activity in the bovine lung

Roets

Burvenich

1995

Vet Res Commun

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Muscarinic and beta-adrenoceptors were identified in airway epithelium, smooth muscle and lung parenchyma from Holstein-Friesian calves and cows and were characterized with [3H]quinuclidinyl benzilate and [3H]dihydroalprenolol, respectively. The muscarinic receptor density in the smooth muscle of cows (Bmax = 4803 +/- 245 fmol/mg protein) was 33% greater (p < 0.01) than in calves. Low receptor numbers were detected in the epithelium and parenchyma. In both calves and cows, the density of epithelial beta-adrenoceptors was twice as high as in smooth muscle and parenchyma. The quantity of beta-adrenoceptors in the tracheal epithelium (Bmax = 994 +/- 83 fmol/mg protein) and smooth muscle (Bmax = 492 +/- 41 fmol/mg protein) in cows was respectively 37% (p < 0.001) and 35% (p < 0.01) lower than in calves. Adenylate cyclase (AC) assays indicated that the basal and the (-)-isopropylnoradrenaline- (ISO-) stimulated cAMP production were not significantly different between the calves and cows. After stimulation with NaF, significantly higher cAMP production was found in all tissues from cows. Significant correlations were found between absolute AC responses to NaF and beta-adrenoceptor density in epithelium (r = -0.75, p < 0.001) and smooth muscle (r = -0.63, p < 0.01). It seems that, in older animals, the production of cAMP is independent of the number of receptors, indicating the presence of fully active compensatory mechanisms.

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Section: Discussionsupporting

confidence: 84%

The influence of ageing on muscarinic receptors, β-adrenoceptors and adenylate cyclase activity in the bovine lung

Roets

Burvenich

1995

Vet Res Commun

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“…Clenbuterol was designed to act as bronchodilator for the treatment of asthma. It directly acts via β2-adrenergic receptors in lung tissue resulting in relaxation of the bronchial muscles [17]. Another physiological effect of clenbuterol is an increased heart rate [28].…”

Section: Discussionmentioning

confidence: 99%

“…It mainly binds to β2adrenergic receptors, which are present in the bronchial tubes and in lung tissue. It has a direct effect on smooth muscles in the lung [17]. In contrast, there is not much known about the effect of steroid hormones on lung tissue, yet.…”

Section: Special Issue: Food Safety and Hygienementioning

confidence: 98%

Development of a Uniform Biomarker Signature in Calves Heart and Lung to Detect the Abuse of Different Anabolic Substances

Riedmaier¹

2015

JNHFS

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Anabolic agents like steroid hormones or β-agonists are used in food-producing animals in order to increase muscle mass and reduce fat content [1,2]. The application of specific anabolic agents in animal husbandry is allowed and common in different countries, e.g. USA, Canada, South Africa, etc. Due to proven side effects of substance residues for the consumer, the use of all growth promoting agents is forbidden within the European Union (EU)

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?-Adrenoceptor regulation and functional responses in the guinea-pig following chronic administration of the long-acting ?2-adrenoceptor agonist formoterol

Kompa

Molenaar

Summers

1995

Naunyn-Schmiedeberg's Arch Pharmacol

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Formoterol is a long acting beta 2-adrenoceptor agonist designed for the alleviation of the symptoms of asthma. This study examined the effects of 14 day administration of formoterol (200 micrograms/kg/day i.p.) on beta 1- and beta 2-adrenoceptors in guinea-pig cardiac and lung tissue. Quantitative autoradiography was used to measure changes in receptor density and organ bath studies determined alterations in functional response. Formoterol treatment produced marked reductions of between 43% and 77% in beta 2-adrenoceptor density in all regions of the heart (atrioventricular node, bundle of His, right and left bundle branches, interventricular and interatrial septa, right and left atria, ventricles and apex) and lung (bronchial and vascular smooth muscle and parenchyma) (P < 0.01, n = 6). beta 1-Adrenoceptor density remained unchanged in all cardiac and lung regions. In functional studies (-)-isoprenaline was 4 fold less potent at causing relaxation of carbachol (1 microM) precontracted tracheal smooth muscle (pD2: control 8.49 +/- 0.03, formoterol 7.91 +/- 0.10, P < 0.001, n = 4), but formoterol treatment did not change the ability of (-)-isoprenaline to elicit a maximum response. The pKB values for ICI 118,551, 7.33 +/- 0.08 in the control and 7.20 +/- 0.01 in formoterol treated animals, were between those expected for beta 1- and beta 2-adrenoceptors suggesting involvement of both subtypes in the response. In spontaneously beating right atria and electrically paced left atria, tissues in which responses are largely mediated by beta 1-adrenoceptors, there was no significant change in responses to (-)-isoprenaline (right atria pD2: control 8.45 +/- 0.02; formoterol 8.42 +/- 0.11; P = 0.77, n = 4) (left atria pD2: control 8.25 +/- 0.03; formoterol 8.47 +/- 0.08; P = 0.09, n = 4). In the presence of CGP 20712A (100 nM) the pKB values did not change with formoterol treatment (left atria: control 9.59 +/- 0.12, formoterol 9.66 +/- 0.12; P = 0.70, n = 4) (right atria: control 8.93 +/- 0.11, formoterol 9.11 +/- 0.07; P = 0.25, n = 4). The doses and route of administration of formoterol used in this study differs from those used clinically. However, this study demonstrates that chronic formoterol administration produces selective down-regulation of beta 2-adrenoceptors in the lung and heart. The changes in the lung are accompanied by a shift to the right in the concentration-response curve to beta-agonist stimulation with no change in the maximum response.

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Effect of clenbuterol on beta‐adrenoceptors and adenylate cyclase activity in smooth muscle and epithelium of the trachea of calves

Cited by 3 publications

References 8 publications

The influence of ageing on muscarinic receptors, β-adrenoceptors and adenylate cyclase activity in the bovine lung

The influence of ageing on muscarinic receptors, β-adrenoceptors and adenylate cyclase activity in the bovine lung

Development of a Uniform Biomarker Signature in Calves Heart and Lung to Detect the Abuse of Different Anabolic Substances

?-Adrenoceptor regulation and functional responses in the guinea-pig following chronic administration of the long-acting ?2-adrenoceptor agonist formoterol

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