Background: Angiotensin converting enzyme (ACE) upregulation in stromal cells of joints affected by rheumatoid arthritis may lead to higher tissue angiotensin II that is a vasoconstrictor and mitogen factor. To date, the role of angiotensin II on regulating blood flow in inflamed joints has not been studied. Methods: Acute and chronic joint inflammation was induced in rabbits by intra-articular...

The levels of noradrenaline, neuropeptide Y, 5-hydroxytryptamine, and substance P were measured and compared between the large arteries of the circle of Willis and the small cerebral vessels of the pia mater in the rat, rabbit, cat, and monkey. In all species, noradrenaline and neuropeptide Y concentrations were greater in the larger arteries than in small pial vessels. Noradrenaline concentrat...

BACKGROUND JM-1232(-) is a novel anesthetic agent which acts through gamma-aminobutyric acid receptors. Cerebral pial vascular effects of JM-1232(-) are unknown. We thus evaluated topical and intravenous effects of JM-1232(-) on cerebral pial microvessels in rabbits, and the extent to which carbon dioxide (CO2) reactivity is preserved. METHODS Closed cranial windows were used to visualize cer...

Human vascular malformations cause disease as a result of changes in blood flow and vascular hemodynamic forces. Although the genetic mutations that underlie the formation of many human vascular malformations are known, the extent to which abnormal blood flow can subsequently influence the vascular genetic program and natural history is not. Loss of the SH2 domain-containing leukocyte protein o...

BACKGROUND AND PURPOSE Nicorandil, a potent antianginal agent characterized as a potassium channel opener, could produce cerebrovascular dilation in in vitro studies. Our aim was to investigate the pharmacologic response to the topical application of nicorandil on the vasomotor tone of pial vessels in vivo. To elucidate its mechanism, we also studied the inhibitory action of methylene blue and ...

The blood supply of the optic nerve has been a subject of controversy for at least 200 years, since the description of the arterial circle around the optic nerve head by Zinn (1755) and Haller (1754). Numerous papers have been written concerning the subject and in the past few years new techniques of injection, micro-angiography, and dissection and Neoprene casts have resulted in further papers...

Little is known regarding the changes in blood oxygen tension (P(O2)) with changes in brain function. This work aimed to measure the blood P(O2) in surface arteries and veins as well as tissue with evoked somato-sensory stimulation in the anesthetized rat. Electrical stimulation of the forepaw induced average increases in blood flow of 44% as well as increases in the tissue P(O2) of 28%. More i...

We studied pial vessels in vivo in mice, examining under mercury light the permeability of these vessels to sodium fluorescein. Topical application of hypertonic solutions of NaCl caused leakage of fluorescein. However, putative chemical mediators of leakage, such as histamine, serotonin, arachidonic acid, and bradykinin, all failed to increase permeability to the dye. Apparent increases in per...

We induced experimental concussive brain injury by a fluid percussion device in anesthetized cats equipped with a cranial window for the observation of the pial microcirculation of the parietal cortex. Brain injury resulted in transient but pronounced increases in arterial blood pressure and in sustained arteriolar vasodilation associated with reduced or absent responsiveness to the vasoconstri...

adenosine has many of the characteristics of a regulator of cerebral blood flow and adenosine receptors change in morphine dependency. in this study the changes in adenosine receptors' responsiveness of pial vessels in the hind limb area of the sensory cortex were evaluated in morphine dependent rats (mdr) using the laser doppler flowmetry technique. adult male sprague dawley rats (250-350...