Canine dilated cardiomyopathy: lymphocyte and cardiac alpha(1)- and beta-adrenoceptor concentrations in normal and affected great danes.
Serum catecholamine levels and myocardial and lymphocyte adrenergic receptor (AR) concentrations were measured in adult great danes affected by canine dilated cardiomyopathy (DCM) and compared to those of healthy animals. A non-homogeneous population of beta -AR, consisting of beta(1)-AR and beta(2)-AR, was observed in healthy (41 and 59%, respectively) and affected (17 and 83%, respectively) dog lymphocytes. Binding assays revealed that total beta -AR, beta(1)-AR and alpha(1)-AR were significantly downregulated (P<0.05;P<0.01;P<0. 001), both in lymphocyte and myocardial cell membranes of affected dogs. beta(2)-Adrenergic receptor concentrations were significantly reduced only in lymphocyte and right atrium cell membranes (P<0.05). Downregulation was not associated with alterations in receptor binding characteristics, as no significant differences in K(d)values were found. Mean plasma catecholamine levels were significantly higher (P<0.01) in DCM dogs (939+/-41) than in normal subjects (348+/-32), thus suggesting a sympathetic activation. The present study indicates a condition similar to that observed in human patients affected by DCM and that adrenergic receptors in canine lymphocytes reflect the fluctuation of adrenergic receptor concentrations in the myocardium.
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Department of Animal Pathology, Division of Veterinary Pharmacology & Toxicology, via Nizza 52, Torino, I-10126, Italy.
Bergamasco
L
L
Badino
P
P
Borgarelli
M
M
Odore
R
R
Tarducci
A
A
Zanatta
R
R
Girardi
C
C
D000317:Adrenergic alpha-Antagonists / Q000737:chemistry; D000319:Adrenergic beta-Antagonists / Q000737:chemistry; D000818:Animals; D002311:Cardiomyopathy, Dilated / Q000097:blood / Q000503:physiopathology / Q000662:veterinary*; D002395:Catecholamines / Q000097:blood; D004283:Dog Diseases / Q000097:blood / Q000503:physiopathology*; D004285:Dogs; D004562:Electrocardiography / Q000662:veterinary; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000503:physiopathology / Q000662:veterinary*; D018655:Lymphocyte Count / Q000662:veterinary; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D011224:Prazosin / Q000737:chemistry; D011412:Propanolamines / Q000737:chemistry; D011941:Receptors, Adrenergic / Q000032:analysis* / Q000097:blood; D018340:Receptors, Adrenergic, alpha-1 / Q000032:analysis / Q000097:blood / Q000737:chemistry; D018342:Receptors, Adrenergic, beta-1 / Q000032:analysis / Q000097:blood / Q000737:chemistry; D018343:Receptors, Adrenergic, beta-2 / Q000032:analysis / Q000097:blood / Q000737:chemistry
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D011412:Propanolamines; D011941:Receptors, Adrenergic; D018340:Receptors, Adrenergic, alpha-1; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; C026777:ICI 118551; C033394:CGP 12177; D011224:Prazosin