title: Role of alpha 1-adrenergic receptors and the effect of bunazosin on the histopathology of cardiomyopathic Syrian hamsters of strain BIO 14.6.
abstract: In order to clarify the pathological involvement of the sympathetic nervous system in the development of cardiomyopathy, a receptor-binding study was carried out on cardiomyopathic Syrian hamsters of strain BIO 14.6 (BIO) at 21 days (prenecrotic stage); 35-42 days (onset of cardiomyopathy); and 70-84 days of life (early cardiac hypertrophy). The newly developed alpha 1-blocker (bunazosin hydrochloride) was initially administered at doses of 100 micrograms/kg or 10 mg/kg to BIO hamsters at 21 days of life and continued for 70 days. At the onset of cardiomyopathy and early cardiac hypertrophy, there was an increase in the number of alpha 1-receptors in the BIO hamsters compared to controls, but there were no significant changes at the prenecrotic stage. On histopathological examination, 10 mg/kg bunazosin had a significant beneficial effect on cardiomyopathy [area of necrosis 1.38% in untreated vs 0.33% in treated animals; area of calcification 2.70% (untreated) vs 0.60% (treated); area of all myocardial injuries 6.97% (untreated) vs 3.19% (treated)]. However, 100 micrograms/kg bunazosin had no effect. It was concluded that the increase in the number of alpha 1-receptors may not be involved in the pathogenesis of cardiomyopathy but that alpha 1-receptors could be implicated in the later progression of the condition.
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D009202:Cardiomyopathies / Q000378:metabolism* / Q000473:pathology; D006224:Cricetinae; D005260:Female; D008297:Male; D008647:Mesocricetus; D009206:Myocardium / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism
chemical_list: D000317:Adrenergic alpha-Antagonists; D011799:Quinazolines; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; C018176:bunazosin