Hypertension and brain oedema: an experimental study on acute and chronic hypertension in the rat.

Johansson, Barbro; Linder, Lars

doi:10.1136/jnnp.44.5.402

Cited by 20 publications

(4 citation statements)

References 27 publications

(16 reference statements)

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“…Our results show a linear correlation between water content and specific gravity during development. In agreement with studies on adult brain, the standard deviation is consistently smaller with the specific gravity method, which facilitates the detection of differences between experimental groups (Nelson et al 1971, Johansson & Linder 1981.…”

Section: Discussionsupporting

confidence: 84%

Specific gravity of brain tissue during maturation

Johansson

Linder

2009

Acta Neurologica Scandinavica

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The water content of the brain is closely related to the maturation and degree of myelination. In control rats studied from the day of birth to the age of 26 days, brain specific gravity increased in parallel to the decrease in water content (r= 1.00). Rats treated with 6‐hydroxydopamine (6‐OHDA) 100 μg/g daily during the first 2 or 4 days of life had significantly lower specific gravity than controls in all parts of the brain at the age of 2 weeks. With the smaller dose 6‐OHDA, the specific gravity at the age of 1 month was lower than in controls in the occipital cortex; with the larger dose it was significantly reduced in all cortical regions as well as in the pons and the diencephalon. 2‐months old 6‐OHDA treated rats did not differ from controls. Rats pretreated with desipramine 30 min before administration of 6‐OHDA to prevent uptake of 6‐OHDA into catecholaminergic neurons did not differ from controls. Neonatal 6‐OHDA treatment affects predominantly noradrenergic terminals in the cerebral cortex with cell bodies in the locus coeruleus. The present results are consistent with the hypothesis that these neurons have a trophic influence on the brain development during the postnatal maturation.

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Section: Discussionsupporting

confidence: 84%

Specific gravity of brain tissue during maturation

Johansson

Linder

2009

Acta Neurologica Scandinavica

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“…Although all these factors may contribute to changes in BBB permeability, it is quite difficult to separate them from each other because they are interdependent, representing various manifestations of METH‐induced metabolic activation. For example, although acute hypertension, as the part of autonomic activation induced by psychomotor stimulant drugs, may affect BBB permeability (see Johansson, 1980; Johansson & Linder, 1981), it is unlikely that this factor alone is directly responsible for robust METH‐induced BBB leakage.…”

Section: Discussionmentioning

confidence: 99%

Brain edema and breakdown of the blood–brain barrier during methamphetamine intoxication: critical role of brain hyperthermia

Kiyatkin

Brown

Sharma

2007

Eur J of Neuroscience

121

139

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To clarify the role of brain temperature in permeability of the blood-brain barrier (BBB), rats were injected with methamphetamine (METH 9 mg/kg) at normal (23 degrees C) and warm (29 degrees C) environmental conditions and internal temperatures were monitored both centrally (nucleus accumbens, NAcc) and peripherally (skin and nonlocomotor muscle). Once NAcc temperatures peaked or reached 41.5 degrees C (a level suggesting possible lethality), animals were administered Evans blue dye (protein tracer that does not normally cross the BBB), rapidly anaesthetized, perfused and had their brains removed. All METH-treated animals showed brain and body hyperthermia associated with relative skin hypothermia, suggesting metabolic activation coupled with peripheral vasoconstriction. While METH-induced NAcc temperature elevation varied from 37.60 to 42.46 degrees C (or 1.2-5.1 degrees C above baseline), it was stronger at 29 degrees C (+4.13 degrees C) than 23 degrees C (+2.31 degrees C). Relative to control, METH-treated animals had significantly higher brain levels of water, Na(+), K(+) and Cl(-), suggesting brain edema, and intense immunostaining for albumin, indicating breakdown of the BBB. METH-treated animals also showed strong immunoreactivity for glial fibrillary acidic protein (GFAP), possibly suggesting acute abnormality or damage of astrocytes. METH-induced changes in brain water, albumin and GFAP correlated linearly with NAcc temperature (r = 0.93, 0.98 and 0.98, respectively), suggesting a key role of brain hyperthermia in BBB permeability, development of brain edema and subsequent functional and structural neural abnormalities. Therefore, along with a direct destructive action on neural cells and functions, brain hyperthermia, via breakdown of the BBB, may be crucial for both decompensation of brain functions and cell injury following acute METH intoxication, possibly contributing to neurodegeneration resulting from chronic drug use.

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“…Indeed, both RHR and SHR have been shown to be more susceptible to ischemic brain damage than normotensive WKY, after acute hypotension (Barry et al, 1982). On the other hand, RHR suffer brain ischemia and edema following a sudden increase in blood pressure, presumably due to rupture of the blood brain barrier induced by high blood pressure; this does not occur in normotensive rats (NR) or SHR (Fujishima et al, 1978;Johansson and Linder, 1981). This is also consistent with the observations that the lower limit of cerebral blood flow (CBF) autoregulation are reset to higher blood pressures in chronic hypertensive rats (Fujishima and Omae, 1976;Barry et al, 1982;Sadoshima and Heistad, 1983), in man (Strandgaard et al, 1973) and in the baboon (Jones et al, 1976).…”

Section: Functional Significance Of Cerebral Vessel Innervation In Chmentioning

confidence: 99%

Altered cerebral vessel innervation in the spontaneously hypertensive rat.

Lee¹,

Saito²

1984

Circulation Research

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SUMMARY. Autonomic innervation in the cerebral arterial walls of adult male spontaneously hypertensive rats and of normotensive Wistar-Kyoto rats was studied. When examined by fluorescence microscopy, dense catecholamine fluorescence was observed in anterior cerebral and middle cerebral arteries of both Wistar-Kyoto and spontaneously hypertensive rats. However, vertebral and basilar arteries and small pial arteries of Wistar-Kyoto rats received extremely sparse or no catecholamine fluorescence, whereas, in the respective regions of spontaneously hypertensive rats, catecholamine fluorescence was found to be significantly elevated. The endogenous norepinephrine content was also higher in cerebral arteries of spontaneously hypertensive than of Wistar-Kyoto rats. When examined ultrastructurally (potassium permanganate fixation), the incidence of granular vesicle-containing nerves, indicative of sympathetic nerves, was found to be significantly elevated in all cerebral arteries of spontaneously hypertensive rats examined. In contrast, the agranular vesicle-containing nerve, indicative of nonsympathetic nerves, with close synaptic cleft distance (<2 /im) was found to decrease or remain unchanged in the cerebral arteries of spontaneously hypertensive rats. These results suggest that cerebral sympathetic vasoconstriction may become more prominent than nonsympathetic vasodilation in spontaneously hypertensive rats. This finding lends further credence to the previous in vivo findings that cerebral sympathetic vasoconstrictor nerves become more functional and exhibit a protective effect against brain lesions during hypertension. The potential roles of neurogenic components involved in cerebral blood flow autoregulation are also discussed. (Circ Res 55: 392-403, 1984)

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Hypertension and brain oedema: an experimental study on acute and chronic hypertension in the rat.

Cited by 20 publications

References 27 publications

Specific gravity of brain tissue during maturation

Specific gravity of brain tissue during maturation

Brain edema and breakdown of the blood–brain barrier during methamphetamine intoxication: critical role of brain hyperthermia

Altered cerebral vessel innervation in the spontaneously hypertensive rat.

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