Electron microscopic evidence for innervation of intracerebral arterioles in the cat

Cervós-Navarro, J; Matakas, F.

doi:10.1212/wnl.24.3.282

Cited by 57 publications

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“…Those studies were based on immunofluorescence. More recent evidence, using electron microscopy, also indicates that intracerebral arterioles in the cat are innervated by noradrenergic nerve fibers (18).…”

Section: Resultsmentioning

confidence: 99%

“…Also, changes in hypothalamic blood flow have been shown to depend on the dose of norepinephrine administered (26). The immunofluorescence studies of Hartman and his colleagues (12,17) and the electron microscopic evidence of Cervos-Navarro and Matakas (18) have, thus far, been the most conclusive evidence for adrenergic innervation of cerebral microvessels. Demonstration of the presence in isolated brain microvessels of norepinephrine and the enzymatic machinery necessary for its biosynthesis and catabolism provides additional evidence for neuronal regulation of the cerebral microcirculation.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Presence of norepinephrine and related enzymes in isolated brain microvessels.

Lai¹,

Udenfriend²,

Spector³

1975

Proc. Natl. Acad. Sci. U.S.A.

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Norepinephrine and the enzymes involved in its synthesis and degradation were found to be associated with isolated brain microvessels. The significance of these results are discussed with respect to adrenergic innervation of the cerebral microvessels and thereby neural regulation of the cerebral microcirculation. The cerebral vasculature consists of two systems of blood vessels: intracerebral and extracerebral vessels. Physiological and pharmacological studies of the brain blood vessels have generally been performed on isolated extracerebral arteries, such as pial arteries and basilar artery (1, 2), probably due to the difficulty in isolating the intracerebral vessels. Studies on the intracerebral vessels have usually been confined to histochemical and morphological procedures (1, 3).We were able to isolate microvessels (arterioles, capillaries, and venules) from the rat brain with a modification of the method used by Brendel et al. (4). In the present study, we report on the presence of norepinephrine in these microvessels as well as the enzymes necessary for both its biosynthesis and catabolism. was loosely fitted to the tube (0.5 mm clearance). The homogenates were sieved over a 153-,um nylon fabric, and the filtrate was collected in a beaker immersed in an ice bath. This has been designated as brain filtrate. The brain tissues retained on the nylon cloth were transferred to another test tube and gently homogenized and sieved as before. A relatively homogeneous preparation of microvessels could be obtained by carrying out the homogenization and sieving procedure four times. Homogeneity of the microvessels was examined under a microscope during the course of isolation. The yield of cerebral microvessels obtained from one rat brain was approximately 2 mg wet weight. The combined brain filtrates were centrifuged at 150 X g for 10 min. The precipitate was then resuspended in suitable buffer for determination of enzyme activities. Tyrosine hydroxylase [tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase(3-hydroxylating); EC 1.14.16.2] was determined by a modification of the method of Nagatsu et al. (5). All tissues were homogenized in phosphate buffer (67 mM; pH 6.2): whole brain in 20 volumes, mesenteric arteries in 10 volumes, and microvessels (from four to eight brains) in 80,.ul. The reaction mixture consisted of 0.1 mM L-tyrosine containing about 2 X 105 cpm of L-[3,5-3H]tyrosine; 0.74 mM 2-amino-6-methyl-5,6,7,8,-tetrahydropteridine; 140 mM 2-mercaptoethanol; 200 mM sodium acetate buffer (1 M; pH 6.0); 1000 units of catalase; and tissue homogenates in a total volume of 500 ,ul for brain tissue and 100,u1 for blood vessels. The mixture was incubated for 15 min at 370, and the reaction was then terminated by adding 100 ,u1 of 12.5% trichloroacetic acid for brain, and 500 ,ul of 2.5% trichloroacetic acid for vessels. After centrifugation of the sample, the supernatant was passed over a Dowex column (+H, 200-400 mesh). The effluent and 1.4 ml of water, used to wash the column,...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Presence of norepinephrine and related enzymes in isolated brain microvessels.

Lai¹,

Udenfriend²,

Spector³

1975

Proc. Natl. Acad. Sci. U.S.A.

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“…A second system of neurons associated with the adventitial sheath which surrounds pene trating cortical arterioles, originates in the supe rior cervical ganglion. Some of these axons have been reported to form functional synapses with the vascular smooth muscle (Cervos-Navarro and Matakas, 1974). While the adventitial space can be observed encompassing some of the isolated microvessels ( fig.…”

Section: Discussionmentioning

confidence: 99%

Isolated Brain Microvessels: Preparation, Morphology, Histamine and Catecholamine Contents

Head¹,

Hjelle²,

Jarrott³

et al. 1980

J Vasc Res

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A method for the rapid preparation of parenchymal microvessels from rat, rabbit and bovine brains is described. Light and electron microscopic examination of the isolated microvessels showed the smooth muscle and endothelial cells to be intact and substantially free of neutrophil contamination. The observation of 0.2 to 2.0 µm electron dense granules in the adventitial space associated with some of the isolated arteriolar elements and the identification of histamine in microvessel extracts is suggestive of the presence of mast cells in the microvessel preparations. Age-dependent changes in histamine content and an increased histamine content in microvessels from hypertensive rats were noted. Using a sensitive radioenzymatic assay, the catecholamine (CA) contents of microvessels isolated from cow, rat and rabbit were measured. The total CA contents of all microvessel preparations were small (<0.35 µg g^–1) with norepinephrine being the predominant CA present. A large ratio of dopamine to norepinephrine was found in microvessels from rat and bovine brain. The possible origins of the CAs present in the isolated microvessels are discussed.

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“…The density of the cerebrovascular sympathetic plexus is comparable to that of various other peripheral vascular beds, and the nerve fibres extend at least in baboon and cat along the cerebrovascular tree down to the level of small intraparenchymal arterioles , Cerv6s-Navarro & Matakas 1974. The functional importance of this innervation has been extensively studied during the last few years (for review see …”

Section: Discussionmentioning

confidence: 99%

Cerebrovascular sympathetic denervation and blood‐brain barrier function in conscious rats

Hardebo

Edvinsson

Johansson

1980

Acta Physiologica Scandinavica

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Electrical stimulation of the sympathetic nerves to the cerebrovascular bed enables the resistance vessels to better withstand a high blood pressure in terms of blood-brain barrier integrity. Sympathetic denervation could hence be expected to lead to a decrease in cerebrovascular tone and increased vulnerability of the blood-brain barrier. In the present study acute hypertension was induced in conscious unrestrained rats by administration of angiotensin or bicuculline. The albumin leakage into the brain, as studied by Evans blue-albumin and 125I labelled human serum albumin, was not enhanced in acutely or chronically sympathectomized rats compared to controls.

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Electron microscopic evidence for innervation of intracerebral arterioles in the cat

Cited by 57 publications

References 0 publications

Presence of norepinephrine and related enzymes in isolated brain microvessels.

Presence of norepinephrine and related enzymes in isolated brain microvessels.

Isolated Brain Microvessels: Preparation, Morphology, Histamine and Catecholamine Contents

Cerebrovascular sympathetic denervation and blood‐brain barrier function in conscious rats

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