Determination of ?-adrenoceptors and cAMP in muscle from normal and splayleg Belgian Landrace pigs

Roets, E; Burvenich, Christian; Curvers, P.; Hoorens, J.

doi:10.1007/bf00420835

Cited by 3 publications

(1 citation statement)

References 19 publications

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“…Adenylate cyclase activities were assessed in frozen membranes by the method described previously (Roets et al, 1989). Guanosine 5'-triphosphate (GTP) is required for hormonal stimulation of the enzyme, whereas sodium fluoride (NaF) is able to activate AC in the absence of GTP.…”

Section: Adenylate Cyclase Assaymentioning

confidence: 99%

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: Adenylate Cyclase Assaymentioning

confidence: 99%

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 receptor subtypes, β-adrenoceptors and cAMP in the tracheal smooth muscle of conventional and double-muscled calves

1992

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The total muscarinic (M1 + M2 + M3) and beta-adrenergic receptors in the tracheal smooth muscle of conventional and double-muscled calves were identified and characterized with the non-specific antagonists [3H]quinuclidinyl benzilate ([3H]QNB) and [3H]dihydroalprenolol ([3H]DHA) respectively. Although the quantity of beta-adrenoceptors in double-muscled calves was 25% lower (p < 0.05) than in conventional calves (Bmax = 327 +/- 89 fmol/mg protein), adenylate cyclase assays indicated that the basal adenylate cyclase activity and the (-)-isopropylnoradrenaline (ISO)- and sodium fluoride (NaF)-stimulated values were not significantly different between these calves. However, the density of muscarinic receptors in double-muscled calves was 40% higher (p < 0.01) than in conventional calves (Bmax = 2955 +/- 625 fmol/mg protein). Subtypes of muscarinic receptors were studied with [3H]telenzepine (M1-receptors), [3H]AF-DX 384 (M2-receptors) and [3H]4DAMP (M1 and M3-receptors). It was found that in both double-muscled and conventional calves about 40% of the receptors were of the M3-subtype, the remaining 60% being M2-receptors. From these results, it is suggested that inflammation of the respiratory tract in double-muscled calves may be complicated by an imbalance between the cholinergic bronchoconstrictor and the beta-adrenergic bronchodilator components of the autonomic nervous system.

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

Roets

Burvenich

1993

Veterinary Quarterly

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A potent beta-agonist (clenbuterol) was administered perorally to young calves for 50 days. After this period the animals were slaughtered and beta-adrenoceptor density, ligand affinity, and basal and stimulated adenylate cyclase activities were studied in smooth muscle and epithelium of the trachea. Although the density of lung beta-adrenoceptors was down regulated by clenbuterol, cAMP production remained constant (epithelium) or even increased (smooth muscle). Therefore desensitization of beta-adrenoceptors in the trachea was not observed. This might be a reason for the effectiveness of long-term treatment with beta-agonists.

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Determination of ?-adrenoceptors and cAMP in muscle from normal and splayleg Belgian Landrace pigs

Cited by 3 publications

References 19 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

Muscarinic receptor subtypes, β-adrenoceptors and cAMP in the tracheal smooth muscle of conventional and double-muscled calves

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

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