Astrocytes are increasingly believed to play an important role in neurovascular coupling. Recent in vivo studies have shown that intracellular calcium levels in astrocytes correlate with reactivity in adjacent diving arterioles. However, the hemodynamic response to stimulation involves a complex orchestration of vessel dilations and constrictions that spread rapidly over wide distances. In this...

9. Iwayama T, Furness JB, Burnstock G: Dual adrenergic and cholinergic innervation of the cerebral arteries of the rat. Circulation Research 26:635-646, 1970 10. Rosenblum WI, Kontos HA: The importance of studies of the pial microcirculation. Stroke 5:425-428 (July-Aug) 1974 11. Rosendorff C: The neural control of cerebral vessels — a brief review and a new hypothesis. In Cervos-Navarro J (ed):...

Acute hypertension disrupts the blood-brain barrier and may neutralize the negative charge on cerebral endothelium. The goal of this study was to determine the effects of molecular charge on permeability of the blood-brain barrier during acute hypertension. Intravital fluorescent microscopy and fluorescein-labeled dextrans were used to evaluate disruption of the blood-brain barrier during acute...

Disturbance of capillary perfusions due to leukocyte adhesion, disseminated intravascular coagulation, tissue edema is critical components in the pathophysiology of sepsis. Alterations in brain microcirculation during sepsis are not clearly understood. The aim of this study is to gain an improved understanding of alterations through direct visualization of brain microcirculations in an experime...

BACKGROUND AND PURPOSE The flow-induced relaxation of a branch of the rabbit middle cerebral artery was examined to determine if an endothelial-independent as well as -dependent component occurs in pial as well as systemic small arteries and the possible role of products of the cyclooxygenase and the L-arginine nitric oxide synthase pathways. METHODS Intraluminal flow was achieved by the infu...

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 ...

Microsurgical and microscopic methods were employed in guinea pigs to expose, observe, and measure response characteristics of cerebral cortical pial microvessels and microcirculation to traumatic and nontraumatic experimental subarachnoid hemorrhage. Bleeding produced by vascular micropuncture was associated with a 44.3% arteriolar constriction. Topical application of homologous blood alone pr...

the mechanisms underlying cerebral vasodilatation during hypercapnia are not fully understood. to examine the role of nerves and prostaglandins in the regulation of basal blood flow and in hypercapnia-induced vasodilatation in the cerebral blood vessels of rabbit. cerebral blood flow was measured by laser doppler flow-meter in 18 nzw rabbits anesthetized with sodium pentobarbital.  tetrodetoxin...

Introduction: Inflammatory joint diseases are common in elderly, and regulation of joint blood flow (JBF) is important in these conditions. The aim of this study was to investigate the response of inflamed joint blood vessels to angiotensin (Ang ), a vasoconstrictor factor which has been shown to be produced in inflamed joints locally. Identification of Ang receptor subtypes in joint blood ve...

BACKGROUND AND PURPOSE Middle cerebral artery (MCA) stenosis and occlusion may cause ischemic symptoms through both hemodynamic and embolic mechanisms. The purpose of this investigation was to determine the hemodynamic effects of these lesions. METHODS Ten patients with angiographically confirmed symptomatic occlusion (n = 5) or stenosis (n = 5) of the M1 segment of the MCA were studied by cl...