Effects of aortic pressure and vasoactive agents on the vascular resistance of the vasa vasorum in canine isolated thoracic aorta.

Abstract

SUMMARY1. We have developed a new preparation for continuously measuring changes in vascular resistance of the vasa vasorum of the canine isolated thoracic aorta perfused at a constant flow rate with Krebs-bicarbonate solution.2. An increase of more than 150 mmHg in aortic pressure caused a significant increase in the vascular resistance of the vasa vasorum.3. 5-Hydroxytryptamine (5-HT), noradrenaline (NA), adrenaline and dopamine caused dose-dependent increases in the vascular resistance of the vasa vasorum. The decreasing order of potency in the vasoconstrictor responses was as follows: 5-HT >> NA = adrenaline >> dopamine. The 5-HT-and adrenaline-induced vasoconstrictor responses were inhibited by methysergide and by phentolamine plus propranolol, respectively. 4. Acetylcholine (ACh), isoprenaline (ISP), histamine (His), ATP, ADP and adenosine produced dose-related decreases in the vascular resistance of aortic vasa vasorum perfused with the Krebs solution containing 10-5 M-NA. The decreasing order of potency in the response was as follows: ACh = ISP > His > > adenosine = ATP = ADP. The ACh-, ISP-and His-induced vasodilator responses were antagonized by atropine, propranolol and famotidine, respectively.5. The results suggest that the preparation described is useful for studying the regulation of vascular resistance of aortic vasa vasorum and that aortic pressure and vasoactive compounds may directly regulate the vascular resistance of the vasa vasorum in canine isolated thoracic aorta.

Neovascularization in Human Atherosclerosis

“…3 The vasa vasorum are also sensitive to acetylcholine, histamine, isoprenaline, adenosine triphosphate, adenosine diphosphate, adenosine, and sodium nitroprusside. 4 Additionally, precontracted vasa exhibit endothelium-dependent vasodilatation to bradykinin and substance P, which are mediated by endothelium-dependent hyperpolarization and nitric oxide, respectively. 4 As a result, vasa response to some agonists seems different from that of other vessels of similar caliber.…”

“…4 Additionally, precontracted vasa exhibit endothelium-dependent vasodilatation to bradykinin and substance P, which are mediated by endothelium-dependent hyperpolarization and nitric oxide, respectively. 4 As a result, vasa response to some agonists seems different from that of other vessels of similar caliber. The molecular mechanisms underlying this selectivity are not completely elucidated but may involve hypoxia, primarily mediated by the hypoxiainducible factor-1␣ (HIF-1␣).…”

Types of vascular wall as related to vasa vasorum in common tree shrew (Tupaia glis)

“…They are called vasa vasorum interna and vasa vasorum externa, respectively (Gössl et al, 2003;Lametschwandtner et al, 2004;Schoenenberger and Mü ller, 1960). Beyond being the channels for passive blood flow, the vasa vasorum actively regulate the amount of blood supplying the vascular wall (Heistad et al, 1978;Ohhira and Ohhashi, 1992;Scotland et al, 1999). For a number of reasons, the vasa vasorum are not found in all blood vessels.…”

Ruptura dos vasa vasorum e hematoma intramural da aorta: um paradigma em mudança

“…The inner media remains nourished by diffusion from the arterial lumen. [15][16][17][18][19][20][21][22] These factors result in two regions with distinct characteristics in the media: a more elastic inner region and a stiffer outer region. Due to the differences in the two regions' elastic moduli, an increased shear stress occurs in this interface.…”