摘要:

For several years, an in vivo model for the induction and on-line quantification of arterial platelet thrombosis in mesenteric arteries of a small laboratory animal species has been developed in our laboratory. In the present paper, we further document the intimal lesions and the ADP superfusion-induced local platelet thrombus as seen in the scanning electron microscope. The surface morphology of the intimal lesion, induced by electric current, shows a circular or slightly oval denuded area, affecting about 15–20 endothelial cells. The edge of this lesion is often occupied by partially disrupted and detached endothelial cells. The successive embolizations of several ADP thrombi clean this edge and augment the denuded area. The final lesion never exceeds the area of 30–40 endothelial cells. ADP-induced platelet thrombi invariably appear as loose, sponge-like platelet aggregates, very bloodstream-lined, anchored on the denuded subendothelium. There is an excellent correlation between the in vivo light microscopic observations and the actual ultrastructure of this platelet m

ISSN:1018-1172    

DOI:10.1159/000158620

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

We measured blood vessel wall oxygen tension (PO2) in vivo in the tissue and on the surface of dog thoracic aortas and femoral arteries. The overall mean tissue PO2 in the outer vascular wall supplied by vasa vasorum for both blood vessels was 49.4 ± 2.6 (SE) Torr for 42 sites in 8 dogs. Changes in PO2 were measured after intravenous injections of adenosine and epinephrine. There was some tendency for the PO2 to decrease with epinephrine for both vessels. With adenosine the thoracic aorta wall tissue PO2 increased significantly (+23.2 ± 6.0 Torr, p < 0.025), while the femoral artery did not. One possible interpretation of these results is that the vasa vasorum of the thoracic aorta are capable of changing blood flow and oxygen supply to the outer wall to a greater degree than the femoral arter

ISSN:1018-1172    

DOI:10.1159/000158621

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

Plasma-membrane-enriched fractions of canine aortic smooth muscle possess an ATP-supported Ca2+ accumulation which has an absolute requirement for Mg2+ and a high affinity for Ca2+ (Km ∼ 0.5 µM). The rate of ATP-supported Ca2+ transport is not affected by several calmodulin antagonists, but is stimulated by exogenously added calmodulin. The maximal effect of calmodulin on the rate of ATP-dependent Ca2+ transport (at 5.0 µM Ca2+) occurs at 10 µg/ml calmodulin and represents an approximately 3-fold stimulation. This calmodulin stimulation of Ca2+ transport does not require pretreatment of the membranes by EGTA and is an intrinsic property of the plasma membranes. A high-affinity Ca2+-ATPase (Km for Ca2+ ∼0.5 µM) is also present in the aortic smooth muscle plasma membrane. This high-affinity Ca2+-ATPase does not require Mg2+ for catalytic activity, but is in fact inhibited by increasing Mg2+ concentrations. Calmodulin at concentrations effective for the stimulation of the ATP-dependent Ca2+ transport has no effect on the high-affinity Ca2+-ATPase activity or on the basal ATPase activity stimulated by 5 mM Mg2+ or Ca2+. Our results indicate that isolated plasma membranes of canine aortic smooth muscle contain no endogenous calmodulin. The ability of exogenously added calmodulin to stimulate the rate of ATP-dependent Ca2+ transport by vascular smooth muscle plasma membranes suggests that calmodulin may play a role in lowering the cytoplasmic concentration of ionized calcium during vasodilatation. An Mg2+-independent, but not an Mg2+-dependent high-affinity Ca2+-ATPase, was identified in the plasma membranes. This may be separate from the plasmalemmal Ca2+

ISSN:1018-1172    

DOI:10.1159/000158622

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

An understanding of blood flow requires a detailed picture of vascular and microvascular anatomy. To this end an investigation of the arteries feeding the spinotrapezius muscle in normotensive and spontaneously hypertensive rats was performed. Arteries were dilated and filled with resin materials and analyzed quantitatively for their network pattern and vessel geometry. The results show that there exists extensive meshworks of interconnected arteries forming an interorgan plexus. The spinotrapezius muscle has multiple inflows from the thoracodorsal and intercostal arteries which interconnect in an arcade network in the muscle. Some but not all arteries of hypertensive rats are narrower in the dilated state at 100 mm Hg inflation pressure than their controls. Arterioles within the muscle proper, however, are not significantly different, suggesting that lumen narrowing of structural origin is progressively reduced towards the microcirculation.

ISSN:1018-1172    

DOI:10.1159/000158623

出版商:S. Karger AG    

年代:1986

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158624

出版商:S. Karger AG    

年代:1986

数据来源: Karger