Effects of chronic administration of β-blockers on airway responsiveness in a murine model of heart failure.
Lung function abnormalities, both at rest and during exercise, are frequently observed in patients with chronic heart failure (HF), also in absence of respiratory disease. It has been documented that, in HF, chronic adrenergic stimulation down-regulates β-adrenoceptors (β-ARs) and modifies airway relaxant responses. This study was designed to investigate in an animal model of HF whether a treatment with a β-AR blocker, metoprolol, could modify the altered airway hyperresponsiveness. In rats, randomly assigned to 3 experimental groups sham-operated rats (SH), rats with HF induced by left anterior descending coronaric occlusion (HF n = 10), and rats treated with metoprolol 100 mg/kg/die (MET = 10), HF was evaluated after 10 weeks and resulted in increases in plasma norepinephrine and epinephrine and left ventricular end diastolic pressure. β2-ARs and G-protein-βAR2-kinase (GRK2) mRNA levels were determined by real time reverse transcriptase PCR. Carbachol-precontracted isolated tracheal rings were used to functionally assess airway smooth muscle relaxation. In pulmonary tissues, β2-AR mRNA level was significantly decreased in HF groups (-48.73 ± 5.18%, P < 0.01); in the same groups the GRK2 mRNA-levels were significantly enhanced (+222.50 ± 6.13%, P < 0.001); in lung deriving from MET groups the levels of mRNA were significantly increased (+339.86 ± 11.26%, P < 0.001), while the GRK2 mRNA-levels unchanged (-59.02 ± 3.97%, P < 0.001), when compared to SH groups. Relaxation of tracheal strips in response to salbutamol was significantly reduced in HF groups; in tracheal rings, deriving from MET groups, the relaxant effects of salbutamol were significantly enhanced (SH, Emax: 34.87 ± 2.98%, pD2: 7.45 ± 0.27; HF, Emax: 34.87 ± 2.98%, pD2: 7.45 ± 0.27; MET, Emax: 85.43 ± 6.80%, pD2: 6.95 ± 0.59, P < 0.001). In HF, the down-regulation of pulmonary β-ARs results in a significant attenuation of airway relaxation. These effects have been reversed by a treatment with metoprolol, suggesting a potential role of β-AR blockers in the treatment of patients suffering from HF and chronic obstructive airway diseases.
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy; Regional Centre for Pharmacovigilance and Pharmacoepidemiology, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy.
B
B
Rinaldi
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy; Regional Centre for Pharmacovigilance and Pharmacoepidemiology, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy.
A
A
Capuano
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy.
G
G
Gritti
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy.
M
M
Donniacuo
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy.
A
A
Scotto Di Vettimo
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy.
L
L
Sodano
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy; Regional Centre for Pharmacovigilance and Pharmacoepidemiology, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy.
C
C
Rafaniello
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy; Regional Centre for Pharmacovigilance and Pharmacoepidemiology, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy.
F
F
Rossi
Centre of Excellence for Cardiovascular Diseases, Dept. of Experimental Medicine, Section of Pharmacology "L. Donatelli", Second University of Naples, Italy. Electronic address: mariagabriella.matera@unina2.it.
M G
MG
Matera
D058671:Adrenergic beta-1 Receptor Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D058666:Adrenergic beta-2 Receptor Agonists / Q000494:pharmacology; D000420:Albuterol / Q000494:pharmacology; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000187:drug effects; D004837:Epinephrine / Q000097:blood; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000235:genetics; D006333:Heart Failure / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008790:Metoprolol / Q000008:administration & dosage / Q000494:pharmacology*; D009638:Norepinephrine / Q000097:blood; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D018343:Receptors, Adrenergic, beta-2 / Q000187:drug effects / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D058671:Adrenergic beta-1 Receptor Antagonists; D058666:Adrenergic beta-2 Receptor Agonists; D012333:RNA, Messenger; D018343:Receptors, Adrenergic, beta-2; C496569:Grk2 protein, rat; D054769:G-Protein-Coupled Receptor Kinase 2; D008790:Metoprolol; D000420:Albuterol; D009638:Norepinephrine; D004837:Epinephrine
Airway relaxant responses; Heart failure; β-AR blockers