SOME ULTRASTRUCTURAL CHARACTERISTICS OF RENAL-ARTERY AND ABDOMINAL-AORTA IN RAT

  • 1 January 1978
    • journal article
    • research article
    • Vol. 125  (MAR) , 641-652
Abstract
The rat renal artery and abdominal aorta were studied by light microscopy and EM. In rats of 200 g body wt the extracellular space in aortic media ranges between 50-60% and that of the distal renal artery between 15-25%. The surface to volume ratio of aortic smooth muscle cells was 2.7 .mu.m2/mm3 compared to 1.6 .mu.m2/.mu.m3 in the distal renal artery. Dense bodies were rare in aortic smooth muscle cells but were abundant in those of the distal renal artery. Other ultrastructural details of the smooth muscle cells were similar in the 2 types of artery. Cell-to-cell contacts consisted of simple apposition of plasma membranes, and their number was proportional to the total length of cell membrane profile. Mitochondria represented 7-8% of cell volume in both arteries. The proximal renal artery showed structural characteristics which were intermediate between those of the aorta and distal renal artery. In all renal arteries examined, bands of longitudinal smooth muscle were present in the adventitia, principally at branch points. In older rats, regions of discontinuity of the internal elastic lamina were observed.