Oscillatory contractions in tail arteries from genetically hypertensive rats.

Lamb, Fred S.; Myers, Jack D.; Hamlin, Michael N.; Webb, R. Clinton

doi:10.1161/01.hyp.7.3_pt_2.i25

Cited by 34 publications

(29 citation statements)

References 12 publications

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“…The vascular trait examined in this regard was the development of oscillations in generated force in response to norepinephrine in isolated tail arteries of stroke-prone SHR (SHRSP). This norepinephrineinduced oscillatory activity has been described previously 9 ' 10 and has been observed only in SHRSP under the conditions of our experiments. A genetic analysis of blood pressure and the frequency of occurrence of norepinephrine-induced oscillations in tail arteries was performed on the offspring of matings of SHRSP and normotensive Wistar-Kyoto rats (WKY).…”

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confidence: 88%

Genetic association of hypertension and vascular changes in stroke-prone spontaneously hypertensive rats.

et al. 1986

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Isolated tail arteries from stroke-prone spontaneously hypertensive rats (SHRSP) exhibit oscillatory contractile activity in response to norepinephrine, whereas those from normotensive Wistar-Kyoto rats (WKY) do not. To determine whether the norepinephrine-induced oscillations are related to high blood pressure or to separable genetic differences between strains, the response to norepinephrine was studied in adult SHRSP, WKY, and progeny of genetic crosses of SHRSP and WKY (F1, F2, F1 X SHRSP, F1 X WKY). Helical tail artery strips were mounted in a tissue bath for isometric force recording. Rats were classified as responders if oscillatory activity in the presence of 1.8 X 10(-7) M norepinephrine exceeded 250 mg/10 min (milligrams of force amplitude during a 10-minute interval). The blood pressures (mm Hg +/- SEM; tail cuff method) and percentage of rats exhibiting norepinephrine-induced oscillations were as follows: WKY: 109 +/- 3, 0%; F1: 129 +/- 4, 0%; F2: 150 +/- 4, 38%; F1 X WKY: 137 +/- 3, 9%; F1 X SHRSP: 188 +/- 7, 71%; SHRSP: 207 +/- 7, 100%. The distribution of the frequency of animals with oscillatory activity among the progenies was consistent with the hypothesis that a single gene locus determines the observed difference in oscillatory activity between the WKY and SHRSP strains. The allele from the SHRSP that determines the activity phenotype is recessive to the allele contributed by the normotensive WKY strain. In the segregating F2 progeny, the blood pressure of the responders was higher than that of the nonresponders (161 +/- 6 vs 144 +/- 4 mm Hg; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

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confidence: 88%

Genetic association of hypertension and vascular changes in stroke-prone spontaneously hypertensive rats.

et al. 1986

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“…Lamb et al 22 and Myers et al 23 reported another aspect of abnormal Ca 2+ entry in the artery of hypertensive rats; the tail artery isolated from strokeprone SHR (SHRSP), but not from WKY rats, exhibited an oscillatory contractile response to NE. This abnormal behavior of the tail artery was also not corrected by prolonged administration of hydralazine and hydrochlorothiazide; this behavior suggests a genetic defect in the artery of SHRSP.…”

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confidence: 99%

Chronic inhibition of angiotensin converting enzyme decreases Ca2+-dependent tone of aorta in hypertensive rats.

et al. 1989

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“…In contrast, many previous studies have shown that some isolated smooth muscle preparations generate rhythmic contractions (RCs), mainly arterial beds isolated from hypertensive animals. [4][5][6][7][8] Gap junctions are membrane-localized channels which allow intercellular movement of small molecules (relative molecular mass Յ1000), thereby greatly facilitating intercellular communication and coordination of cellular activities. 9,10) Gap junctions are blocked by heptanol 10,11) and they can be activated or recruited by tetraethylammonium.…”

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The Effects of Gap Junction Modulators on the Rhythmic Contractions in Aortas Isolated from Rats Subjected with Sinoaortic Denervation

Rocha

Araújo

Andrade

et al. 2011

Biological & Pharmaceutical Bulletin

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The sinoaortic denervation (SAD) is a proceeding that interrupts the arterial baroreceptor reflex system. The hemodynamic alterations produced by SAD have been extensively studied in many mammals, including rats. There is general agreement that SAD causes a substantial increase in arterial pressure lability with no changes in the mean level of blood pressure.1-3) Therefore, SAD rats can be used to study physiological changes caused by high arterial pressure lability without sustained hypertension. There are few studies analyzing physiological aspects of isolated vessels of SAD rats.Smooth muscle is frequently classified by the manner in which it responds to excitatory stimulation. Therefore, tonic smooth muscle such as that often found in vasculature, airways, gastrointestinal and urogenital systems responds to contractile agonists by producing a simple steady contraction. In contrast, many previous studies have shown that some isolated smooth muscle preparations generate rhythmic contractions (RCs), mainly arterial beds isolated from hypertensive animals. [4][5][6][7][8] Gap junctions are membrane-localized channels which allow intercellular movement of small molecules (relative molecular mass Յ1000), thereby greatly facilitating intercellular communication and coordination of cellular activities.9,10) Gap junctions are blocked by heptanol 10,11) and they can be activated or recruited by tetraethylammonium. 12,13) Gap junctions play a significant role in establishing smooth muscle cell communication in the uterus, which display intense RCs. 14,15) This oscillatory behavior in the uterus is straight associated with an increase in gap junction complex formation between smooth muscle cells.15) Furthermore, inhibitors of gap junctions such as heptanol 16,17) reduce the RCs in the uterus. Isolated rat aortas normally present tonic and stable contractions when stimulated to contract. However, SAD rat aortas present RCs, which are characterized by cycles of fluctuations in tension. 18) In the present study, we also demonstrated an oscillatory behavior in aortas isolated from SAD rats. Additionally, the effect of heptanol and tetraethylammonium (TEA) was investigated in order to explore the role of gap junctional communication on the RCs and supply a pharmacological consideration of the participation of these cellular coupling on vascular reactivity and RCs in aortas from rats with arterial pressure lability evoked by SAD. MATERIALS AND METHODSSinoaortic Denervation All the procedures were carried out in accordance with the Ethical Animal Committee, Ribeirão Preto Campus, University of São Paulo, Brazil. Male Wistar rats (180-210 g) were used throughout the study. Bilateral sinoaortic denervation was performed according to the method reported by Krieger.19) Briefly, the rats were anesthetized with ketamine (50 mg/kg, intraperitoneally (i.p.)) and xylazine (5 mg/kg, i.p.), and suitably fixed in a supine position. An extensive (3-4 cm) middle incision was made into the neck, and the bilateral sternohyoid muscle was rese...

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Oscillatory contractions in tail arteries from genetically hypertensive rats.

Cited by 34 publications

References 12 publications

Genetic association of hypertension and vascular changes in stroke-prone spontaneously hypertensive rats.

Genetic association of hypertension and vascular changes in stroke-prone spontaneously hypertensive rats.

Chronic inhibition of angiotensin converting enzyme decreases Ca2+-dependent tone of aorta in hypertensive rats.

The Effects of Gap Junction Modulators on the Rhythmic Contractions in Aortas Isolated from Rats Subjected with Sinoaortic Denervation

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