The correlation between the development of sympathetic innervation and the development of medial hypertrophy in jejunal arteries in normotensive and spontaneously hypertensive rats

Scott, T. M.; Pang, S C

doi:10.1016/0165-1838(83)90020-6

Cited by 68 publications

(34 citation statements)

References 9 publications

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“…7 - 8 Two major factors may play significant roles in determination of the contractile responses of an artery: the perivascular nerves 9 and the endothelium. 10 n In the SHR, the picture is further complicated by additional changes in the innervation 12 - 13 and the endothelium. ".14,15 Therefore, a valid comparison of the properties of vascular smooth muscle between the SHR and the WistarKyoto (WKY) rat using intact arteries cannot be achieved unless both neural and endothelial factors have been eliminated.…”

Section: ;14:137-144)mentioning

confidence: 99%

Isolation and characterization of single vascular smooth muscle cells from spontaneously hypertensive rats.

Bolzon

Cheung

1989

Hypertension

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To study the properties of vascular smooth muscle in hypertension without the influence of the nerves and endothelium, a procedure was developed to isolate single smooth muscle cells from tail arteries of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) normotensive control rats. Perfusion of intact arteries with a solution of papain and collagenase produced dense populations of viable cells (more than 10 4 cells/ml) that remained relaxed in the presence of physiological levels of calcium. Contractile responses of smooth muscle cells from the SHR were significantly more sensitive to noradrenallne, potassium depolarization, and the calcium channel agonist Bay K 8644 compared with those from WKY rats. Enhanced sensitivity to calcium in the SHR was also observed on readdition of calcium to cells preincubated in noradrenaline or KC1 in a calcium-free medium. These results provide evidence for alterations in the properties of vascular smooth muscle in the SHR at the single cell level. {Hypertension 1989;14:137-144)

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Section: ;14:137-144)mentioning

confidence: 99%

Isolation and characterization of single vascular smooth muscle cells from spontaneously hypertensive rats.

Bolzon

Cheung

1989

Hypertension

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“…Sympathetic nerve activity is enhanced both in human hypertension (Manica et al, 1993) and in the most similar animal model, spontaneously hypertensive rats (SHR;Judy et al, 1976;Lundin et al, 1984). The density of innervation in arteries of SHR is significantly increased (Scott & Pang, 1983) with a widespread increase in noradrenaline (NA) content in the peripheral vasculature . Morphological changes observed in SHR include thickening of the medial layer of both large and small arteries and increased wall thickness due to hypertrophy and hyperplasia of the smooth muscle cells (Owens et al, 1981).…”

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confidence: 99%

Enhanced sympathetic neurotransmission in the tail artery of 1,3‐dipropyl‐8‐sulphophenylxanthine (DPSPX)‐treated rats

Karoon

Rubino

Burnstock

1995

British J Pharmacology

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1 Sympathetic neurotransmission and noradrenaline content of the tail artery of Wistar rats treated for 7 days with the adenosine antagonist, 1,3-dipropyl-8-sulphophenylxanthine (DPSPX), were examined. 2 Systolic blood pressure of the DPSPX-treated rats (164.0 2.9 mmHg; n = 6) was significantly greater than saline-treated controls (140.0 2.8 mmHg; n= 5) after 7 days treatment. 3 The pressor responses of the arterial rings to transmural nerve stimulation (65 V, 0.1 ms, 4-64 Hz, for 1 s) were markedly enhanced in the DPSPX-treated compared with the saline-treated animals. Both noradrenergic and purinergic components of perivascular sympathetic neurotransmission were enhanced during DPSPX-induced hypertension. 4 Vasoconstrictor responses to exogenous noradrenaline (0.1 -300 pM) and adenosine 5'-triphosphate (0.01-3 mM) were unaffected after DPSPX treatment, indicating prejunctional alteration of sympathetic cotransmission during DPSPX-induced hypertension. 5 Acute exposure to DPSPX (10 pM) did not modify vasoconstrictor responses to transmural nerve stimulation, thus supporting the claim that the enhancement of sympathetic neurotransmission only results from long-term DPSPX treatment. 6 The noradrenaline content of the tail arteries of DPSPX-treated (4.498 ± 0.26 ng cm-; n = 4) was significantly greater than saline-treated (3.440 ± 0.30 ng cm-; n = 5) animals. 7 These findings show that chronic inhibition of the actions of endogenous adenosine by DPSPX results in an elevation of systolic blood pressure accompanied by enhanced sympathetic cotransmission and enhanced noradrenaline content of the rat tail artery.

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“…3 Cerebral arteries have a dense sympathetic nerve innervation although the sympathetic effects on CBF have been the subject of intense controversy. 5 Increased sympathetic activity and hyperinnervation are evident in young SHR, 6 suggesting that if an exaggerated sympathetic discharge is interrupted, vascular constrictor response to a rise in blood pressure might be altered. In the present study, we examined whether the upper limit of autoregulation is altered with a rise of resting blood pressure during states of development of hypertension, and whether acute or chronic sympathetic denervation influences CBF autoregulation.…”

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Upper limit of cerebral autoregulation during development of hypertension in spontaneously hypertensive rats--effect of sympathetic denervation.

Sadoshima¹,

Yoshida²,

Ibayashi³

et al. 1985

Stroke

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SUMMARY The upper limit of cerebral autoregulation was studied in pre-or early established hypertension in spontaneously hypertensive rats (SHR). Cerebral blood flow (CBF) was measured with the hydrogen clearance method, and wall/lumen ratio of cerebral arteries was morphometrically measured with the freeze-substitution technique. To test autoregulation, phenylephrine was intravenously infused to cause stepwise increments of blood pressure. Unilateral superior cervical ganglionectomy was carried out to examine the effects of sympathetic denervation on CBF autoregulation and thickness of vascular wall.Resting blood pressure at 4 weeks, 3 months and 6 months of age were 89 ± 3 mm Hg (mean ± SEM), 140 ± 6 and 165 ± 6, respectively. Baseline CBF was slightly diminished with age; 50.6 ± 9.2 ml/100 g/min at 4 weeks, 49.8 ± 8.1 at 3 months and 44.1 ± 5.6 at 6 months. The upper limit of autoregulation was markedly raised with age; 118 ± 5 mm Hg at 4 weeks, 180 ± 7 at 3 months and 208 ± 10 at 6 months. Acute sympathetic denervation lowered the upper limits to 105 ± 2, 162 ± 4 and 185 ± 7 mm Hg, respectively. On the other hand, in chronic denervation which was made at 4 weeks of age, the upper limit of autoregulation in the denervated hemisphere was slightly lower than that in innervated hemisphere at 2 months (165 ± 5 and 178 ± 6 mm Hg), and at 5 months (202 ± 8 and 215 ± 8 mm Hg) after ganglionectomy.Wall to lumen ratio was increased with the elevation of basal blood pressure; 0.131 ± 0.008 at 4 weeks, 0.170 ± 0.005 at 3 months and 0.223 ± 0.007 at 6 months. Chronic denervation reduced such increased ratio to 0.128 ± 0.004 at 2 months and 0.196 ± 0.007 at 5 months after ganglionectomy.We conclude that during development of hypertension, the upward shift of CBF autoregulation is closely related to an elevation of basal blood pressure, which is also correlated to the thickness of vessel wall. By means of tonic and trophic effects, sympathetic innervation appears to play an important role in regulation of CBF in response to acute elevations of systemic blood pressure.Stroke Vol 16, No 3, 1985 IN CHRONIC HYPERTENSION, the upper as well as lower limits of cerebral autoregulation are raised as tested by acute elevations of basal blood pressure. Although the mechanisms are not fully understood, results obtained from observations in both humans and experimental animals indicate that hypertensive vascular alterations are primarily responsible for these shifts of autoregulation. 1 -2 Therefore long-term antihypertensive treatment lowers the limits of autoregulation towards those seen in normotensives, 2 which supports the concept that structural adaptations of cerebral vessels to high blood pressure are reversible.The present study was designed to investigate the changes of autoregulatory capacity in early, middle and late phases of sustained hypertension in spontaneously hypertensive rats (SHR). Recent findings of Nordborg and Johansson have shown that the muscularis media/radius ratio of cerebral arteries in early or prehype...

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The correlation between the development of sympathetic innervation and the development of medial hypertrophy in jejunal arteries in normotensive and spontaneously hypertensive rats

Cited by 68 publications

References 9 publications

Isolation and characterization of single vascular smooth muscle cells from spontaneously hypertensive rats.

Isolation and characterization of single vascular smooth muscle cells from spontaneously hypertensive rats.

Enhanced sympathetic neurotransmission in the tail artery of 1,3‐dipropyl‐8‐sulphophenylxanthine (DPSPX)‐treated rats

Upper limit of cerebral autoregulation during development of hypertension in spontaneously hypertensive rats--effect of sympathetic denervation.

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