Expression of Smooth Muscle Myosin Heavy Chain B in Cardiac Vessels of Normotensive and Hypertensive Rats

• Published in: Circulation research Vol. 83; no. 2; pp. 204 - 209
• Main Authors: Wetzel, Ulrike, Lutsch, Gudrun, Haase, Hannelore, Ganten, Ursula, Morano, Ingo
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD American Heart Association, Inc 27.07.1998; Lippincott; Lippincott Williams & Wilkins Ovid Technologies
• Subjects: Animals; Aorta, Thoracic - metabolism; Aorta, Thoracic - pathology; Arterioles - metabolism; Arterioles - pathology; Biological and medical sciences; Blood vessels and receptors; Blotting, Western; Cerebrovascular Disorders - genetics; Coronary Vessels - metabolism; Coronary Vessels - pathology; Disease Susceptibility; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Heart Ventricles; Hypertension - genetics; Hypertension - metabolism; Hypertension - pathology; Liver - metabolism; Male; Microscopy, Fluorescence; Muscle, Smooth, Vascular - metabolism; Muscle, Smooth, Vascular - pathology; Myosin Heavy Chains - biosynthesis; Myosin Heavy Chains - genetics; Organ Specificity; Rats; Rats, Inbred SHR; Rats, Inbred WKY; RNA Splicing; Urinary Bladder - metabolism; Vertebrates: cardiovascular system; Heart; Hypertension; Rat; Arteriole; Rodentia; Cardiovascular disease; Smooth muscle; Heart ventricle; Gene expression; Microcirculation; Vertebrata; Mammalia; Heart disease; Myosin; Circulatory system; Immunofluorescence; Hypertrophy
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/01.res.83.2.204

We investigated expression of the 5[prime]-spliced isoform of smooth muscle myosin heavy chain (SM-MHC-B) in smooth muscle cells of cardiac vessels of the left ventricle of normotensive (Wistar-Kyoto) and spontaneously hypertensive rats of the stroke-prone strain by immunofluorescence microscopy. In parallel, liver and bladder were studied for characterization of the nature of vessels expressing SM-MHC-B and for semiquantitative evaluation of its abundance. Smooth muscle cells were detected by staining with a monoclonal antibody specific for alpha-smooth muscle actin. Abundance of the SM-MHC-B isoform in these cells was evaluated by using an antibody raised against the seven-amino acid insert at the 25K/50K junction of the myosin head (a25K/50K) that specifically recognized SM-MHC-B. In the ventricle, a25K/50K immunoreactivity was observed in smooth muscle cells of precapillary arterioles but not in larger vessels or aorta. The a25K/50K immunoresponse of those vessels with the highest expression level of SM-MHC-B closely resembled the signal observed in the smooth muscle layer of urinary bladder known to preferentially express SM-MHC-B. Interestingly, in left ventricles of stroke-prone spontaneously hypertensive rats, there was a significantly reduced fraction of a25K/50K-positive precapillary arterioles compared with normotensive control rats. (Circ Res. 1998;83:204-209.)