Differences between longitudinal and circular smooth muscle in β-adrenergic control of motility of isolated equine ileum

Chiara Belloli From the Institute of Veterinary Pharmacology and Toxicology, University of Milan, Via Celoria 10, 20133 Milan (Belloli, Arioli, Carcano, Beretta), and the Department of Animal Pathology, Division of Pharmacology and Toxicology, University of Turin, Via Nizza 52, 10126 Turin (Re, Badino, Odore, Girardi), Italy.

Search for other papers by Chiara Belloli in
Current site
Google Scholar
PubMed
Close
 PhD, DVM
,
Giovanni Re From the Institute of Veterinary Pharmacology and Toxicology, University of Milan, Via Celoria 10, 20133 Milan (Belloli, Arioli, Carcano, Beretta), and the Department of Animal Pathology, Division of Pharmacology and Toxicology, University of Turin, Via Nizza 52, 10126 Turin (Re, Badino, Odore, Girardi), Italy.

Search for other papers by Giovanni Re in
Current site
Google Scholar
PubMed
Close
 PhD, DVM
,
Francesco Arioli From the Institute of Veterinary Pharmacology and Toxicology, University of Milan, Via Celoria 10, 20133 Milan (Belloli, Arioli, Carcano, Beretta), and the Department of Animal Pathology, Division of Pharmacology and Toxicology, University of Turin, Via Nizza 52, 10126 Turin (Re, Badino, Odore, Girardi), Italy.

Search for other papers by Francesco Arioli in
Current site
Google Scholar
PubMed
Close
 MFoodSc
,
Paola Badino From the Institute of Veterinary Pharmacology and Toxicology, University of Milan, Via Celoria 10, 20133 Milan (Belloli, Arioli, Carcano, Beretta), and the Department of Animal Pathology, Division of Pharmacology and Toxicology, University of Turin, Via Nizza 52, 10126 Turin (Re, Badino, Odore, Girardi), Italy.

Search for other papers by Paola Badino in
Current site
Google Scholar
PubMed
Close
 MSc, PhD
,
Roberta Carcano From the Institute of Veterinary Pharmacology and Toxicology, University of Milan, Via Celoria 10, 20133 Milan (Belloli, Arioli, Carcano, Beretta), and the Department of Animal Pathology, Division of Pharmacology and Toxicology, University of Turin, Via Nizza 52, 10126 Turin (Re, Badino, Odore, Girardi), Italy.

Search for other papers by Roberta Carcano in
Current site
Google Scholar
PubMed
Close
 MVM
,
Rosangela Odore From the Institute of Veterinary Pharmacology and Toxicology, University of Milan, Via Celoria 10, 20133 Milan (Belloli, Arioli, Carcano, Beretta), and the Department of Animal Pathology, Division of Pharmacology and Toxicology, University of Turin, Via Nizza 52, 10126 Turin (Re, Badino, Odore, Girardi), Italy.

Search for other papers by Rosangela Odore in
Current site
Google Scholar
PubMed
Close
 MVM
,
Carlo Girardi From the Institute of Veterinary Pharmacology and Toxicology, University of Milan, Via Celoria 10, 20133 Milan (Belloli, Arioli, Carcano, Beretta), and the Department of Animal Pathology, Division of Pharmacology and Toxicology, University of Turin, Via Nizza 52, 10126 Turin (Re, Badino, Odore, Girardi), Italy.

Search for other papers by Carlo Girardi in
Current site
Google Scholar
PubMed
Close
 DVM
, and
Carlo Beretta From the Institute of Veterinary Pharmacology and Toxicology, University of Milan, Via Celoria 10, 20133 Milan (Belloli, Arioli, Carcano, Beretta), and the Department of Animal Pathology, Division of Pharmacology and Toxicology, University of Turin, Via Nizza 52, 10126 Turin (Re, Badino, Odore, Girardi), Italy.

Search for other papers by Carlo Beretta in
Current site
Google Scholar
PubMed
Close
 DVM

SUMMARY

Objective

To identify β-adrenoceptor subtypes involved in motility inhibition of circular and longitudinal smooth muscle layers of equine ileum.

Sample Population

Isolated strips of equine ileum circular smooth muscle and membrane preparations from circular and longitudinal muscle layers.

Procedure

Functional assays of circular muscle preparations and radioligand binding assays and measurements of cAMP production in smooth muscle membranes from circular and longitudinal layers.

Results

Selective β-adrenergic agonists exerted inhibitory effects on circular muscle preparations. Binding studies of cell membranes indicated that the density and distribution of 3 β-adrenoceptor subtypes did not differ between longitudinal and circular muscle layers. Measurement of cAMP production in membrane preparations of longitudinal and circular muscle after selective β-stimulation confirmed presence of the 3 adenylate cyclase-coupled β-adrenoceptor subtypes; however, preparations from the 2 layers had differing cAMP production efficacy.

Conclusions

The data may partly explain the differing functional responses between circular and longitudinal muscle preparations.

Clinical Relevance

Findings support the important role of β-atypical adrenoceptors in the inhibitory regulation of equine ileum motility. (Am J Vet Res 1997;58:1422–1426)

SUMMARY

Objective

To identify β-adrenoceptor subtypes involved in motility inhibition of circular and longitudinal smooth muscle layers of equine ileum.

Sample Population

Isolated strips of equine ileum circular smooth muscle and membrane preparations from circular and longitudinal muscle layers.

Procedure

Functional assays of circular muscle preparations and radioligand binding assays and measurements of cAMP production in smooth muscle membranes from circular and longitudinal layers.

Results

Selective β-adrenergic agonists exerted inhibitory effects on circular muscle preparations. Binding studies of cell membranes indicated that the density and distribution of 3 β-adrenoceptor subtypes did not differ between longitudinal and circular muscle layers. Measurement of cAMP production in membrane preparations of longitudinal and circular muscle after selective β-stimulation confirmed presence of the 3 adenylate cyclase-coupled β-adrenoceptor subtypes; however, preparations from the 2 layers had differing cAMP production efficacy.

Conclusions

The data may partly explain the differing functional responses between circular and longitudinal muscle preparations.

Clinical Relevance

Findings support the important role of β-atypical adrenoceptors in the inhibitory regulation of equine ileum motility. (Am J Vet Res 1997;58:1422–1426)

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 3828 3828 653
PDF Downloads 43 43 3
Advertisement