Increased density of fluorescent adrenergic fibers around the middle cerebral arteries of stroke-prone spontaneously hypertensive rats

1992 ◽  
Vol 61 (1) ◽  
pp. 117-122 ◽  
Author(s):  
Mari Kondo ◽  
Tatsuhiko Miyazaki ◽  
Takashi Fujiwara ◽  
Akemi Yano ◽  
Ryo Tabei
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Cerebral Arteries ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Middle Cerebral Arteries ◽  
Adrenergic Fibers

Hypertension increases middle cerebral artery resting tone in spontaneously hypertensive rats: role of tonic vasoactive factor availability

2008 ◽  
Vol 114 (10) ◽  
pp. 651-659 ◽  
Author(s):  
José M. González ◽  
Beatriz Somoza ◽  
M. Victoria Conde ◽  
Maria S. Fernández-Alfonso ◽  
M. Carmen González ◽  
...  
Keyword(s):  
Cerebral Artery ◽  
Spontaneously Hypertensive Rats ◽  
Cerebral Arteries ◽  
Mesenteric Arteries ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Middle Cerebral Arteries ◽  
Myogenic Responses ◽  
Resting Tone

The present study explores the contribution of alterations in resting tone to cerebral artery narrowing in SHRs (spontaneously hypertensive rats) and the role of hypertension development. Young pre-hypertensive and adult fully hypertensive SHRs and age-matched Wistar–Kyoto rat controls were used. The contribution of basal vasoactive factors to resting tone was studied in middle cerebral arteries with pressure myography. Basal NO and O2− (superoxide anion) availability were determined with fluorescent indicators using confocal microscopy and lucigenin-enhanced chemiluminescence. Basal O2− was also assessed in mesenteric resistance arteries. Middle cerebral arteries from adult rats, but not young pre-hypertensive rats, had augmented myogenic responses and resting tone and decreased relaxation to sodium nitroprusside compared with their normotensive counterparts. Cerebral arteries from adult SHRs also had an increase in tonic NO associated with a decrease in basal O2− availability. Basal O2− was instead increased in mesenteric arteries from SHRs. The present results indicate that large cerebral arteries from SHRs have an increase in their resting tone as a consequence of sustained hypertension and that this is related to a decrease in NO responsiveness. We suggest that this increase in resting tone and myogenic responses could act as a protective mechanism against the development of stroke in SHRs. The present study also demonstrates some unusual findings regarding the current understanding of the NO/O2− balance in hypertension with important differences between vascular beds and draws attention to the complexity of this balance in cardiovascular health and disease.

Prevention of stroke and preservation of the functions of cerebral arteries by treatment with perindopril in stroke-prone spontaneously hypertensive rats

1998 ◽  
Vol 76 (1) ◽  
pp. 26-34 ◽  
Author(s):  
H Wang ◽  
J S Smeda ◽  
RMKW Lee
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Cerebral Arteries ◽  
Subsequent Development ◽  
Treatment Withdrawal ◽  
Prolonged Treatment ◽  
Control Group ◽  
Myogenic Response ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Middle Cerebral Arteries

The aim of this study was to determine whether the prevention of stroke with perindopril treatment in stroke-prone spontaneously hypertensive rats (SHRSP) is associated with the preservation of the myogenic properties of the cerebral arteries. After weaning at 4 weeks of age, male SHRSP were fed a Japanese-style rat diet with high salt to induce stroke development. Treatment with perindopril was given by gavage every morning beginning at 6 weeks of age. There were three experimental groups: two groups treated with 4 mg ·kg-1 ·day-1 perindopril for different durations (8 or 12 weeks) and one control group consisting of littermates given distilled water. All the control animals developed stroke and died within 14 weeks of age, and myogenic response of the middle cerebral arteries (MCA) to pressure increase was lost in these animals. In contrast, all the treated SHRSP survived during the treatment period, and myogenic response of the MCA was preserved. After withdrawal of the treatment, SHRSP treated for a longer period (12 weeks) also survived longer than those treated for a shorter period (8 weeks). The subsequent development of stroke and death following treatment withdrawal after 8 or 12 weeks of treatment was associated with the loss of pressure-dependent constriction in MCA. A longer treatment duration also increased the stiffness of the MCA. MCA from SHRSP after 12 weeks of treatment had smaller external and lumen diameters, and thicker walls than those from the 8-week treatment group. In a separate study, we found that treatment of SHRSP with 1 or 4 mg ·kg-1 ·day-1 of perindopril for 24 weeks beginning at 6 weeks of age also protected them against death related to stroke, because these rats survived up to 43 weeks of age, when the experiment was terminated. We conclude that there is an association between the absence of myogenic response in cerebral arteries and stroke development in SHRSP. Perindopril treatment preserves the myogenic response of MCA in SHRSP and prevents the stroke development in these animals. A prolonged treatment could increase the survival of SHRSP through a remodelling of the MCA and increasing the stiffness of the cerebral arteries.Key words: autoregulation, myogenic response, cerebral artery, stroke, perindopril, hypertension.

Alterations of the Nitric Oxide Pathway in Cerebral Arteries from Spontaneously Hypertensive Rats

2002 ◽  
Vol 39 (3) ◽  
pp. 378-388 ◽  
Author(s):  
Ana M. Briones ◽  
María J. Alonso ◽  
Raquel Hernanz ◽  
Marta Miguel ◽  
Mercedes Salaices
Keyword(s):  
Nitric Oxide ◽  
Spontaneously Hypertensive Rats ◽  
Cerebral Arteries ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Nitric Oxide Pathway

Effects of losartan on cerebral arteries in stroke-prone spontaneously hypertensive rats

1996 ◽  
Vol 14 (11) ◽  
pp. 1341-1348 ◽  
Author(s):  
Elisabeth Vacher ◽  
Christine Richer ◽  
Jean-Fran??ois Giudicelli
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Cerebral Arteries ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive
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