Showing papers by "Suzanne Oparil published in 1995"

Endothelin-receptor antagonist bosentan prevents and reverses hypoxic pulmonary hypertension in rats

Abstract: The current study examined the effects of bosentan, an orally active antagonist of endothelin-A and -B receptors, on the development and maintenance of hypoxia (10% O2)-induced pulmonary hypertensi...

ETA-receptor antagonist prevents and reverses chronic hypoxia-induced pulmonary hypertension in rat

Abstract: The selective endothelin-A (ETA)-receptor antagonist BQ-123 has been shown to prevent chronic hypoxia-induced pulmonary hypertension in the rat. Therefore in the current study we utilized BQ-123 to...

Endothelin-A receptor antagonist prevents acute hypoxia-induced pulmonary hypertension in the rat.

Abstract: Exposure to hypoxia is associated with increased pulmonary artery pressure and plasma endothelin-1(ET-1) levels and with selective enhancement in ET-1 peptide and mRNA and endothelin-A (ETA) recept...

Gender and Dietary NaCl in Spontaneously Hypertensive and Wistar-Kyoto Rats

Abstract: We recently reported that high dietary NaCl exposure significantly increases both daytime and nighttime mean arterial pressure in male spontaneously hypertensive rats (SHR) but only nighttime values in male normotensive Wistar-Kyoto rats (WKY). In the present study we used a telemetry monitoring system to evaluate the effects of high dietary NaCl exposure on diurnal variation of mean arterial pressure and heart rate in male and female SHR and WKY. After implantation of a radio-frequency transducer, rats were fed either high (8%) or basal (1%) NaCl diets for 2 weeks. High dietary NaCl ingestion significantly increased both daytime and nighttime mean arterial pressure in male SHR compared with males receiving a basal NaCl diet, resulting in greater 24-hour values (163±1 versus 154±1 mm Hg, high versus basal NaCl diet; P <.05). High dietary NaCl ingestion significantly increased only nighttime blood pressure in male WKY, with no significant effect on 24-hour mean arterial pressure (102±2 versus 101±3 mm Hg, high versus basal). High dietary NaCl exposure did not affect daytime or nighttime mean arterial pressure in female SHR (24-hour mean arterial pressure, 144±2 versus 141±2 mm Hg, high versus basal NaCl diet). Twenty-four-hour mean arterial pressure tended to be lower in female WKY receiving a high NaCl diet than females ingesting a basal diet (101±3 versus 106±1 mm Hg), but the difference was not significant. These results indicate a sexually dimorphic response to dietary NaCl ingestion, with males of both strains manifesting some degree of NaCl sensitivity, whereas females are NaCl resistant.

Selective downregulation of ANP-clearance-receptor gene expression in lung of rats adapted to hypoxia

Abstract: To test the hypothesis that expression of atrial natriuretic peptide (ANP)-receptor genes is modified to provide a compensatory mechanism against hypoxic pulmonary hypertension, steady state mRNA l...

Hypertensive crisis since FDR--a partial victory.

Abstract: Accelerated, or malignant, hypertension is a disorder whose natural history has been so greatly changed by the availability of effective diagnosis and therapy that many physicians no longer encount...

Hypertension in postmenopausal women: pathophysiology and management.

Abstract: Hypertension, particularly systolic hypertension, afflicts over 50% of postmenopausal women and is an important risk factor for cardiovascular disease in this group. Hormone replacement therapy with estrogen or an estrogen/progestin combination does not alter blood pressure but has beneficial effects on other cardiovascular risk factors, so should be considered in all postmenopausal women unless contraindicated.

Acute Hypertension Increases Norepinephrine Release in the Anterior Hypothalamic Area

Abstract: Neurons in the anterior hypothalamic area play an important role in NaCl-sensitive hypertension in spontaneously hypertensive rats, and previous studies have suggested that baroreceptor feedback modifies the activity of these neurons. To test the hypothesis that the release of norepinephrine in the anterior hypothalamic area is modified by arterial baroreceptor reflex feedback and that this reflex release is disturbed in spontaneously hypertensive rats on a high NaCl diet, we used the push-pull technique to measure the release of the norepinephrine metabolite 3-methoxy-4-hydroxy-phenylglycol in the anterior hypothalamic area. Seven-week-old male spontaneously hypertensive and normotensive Wistar-Kyoto rats were placed on a high (8%) or a basal (1%) NaCl diet for 2 weeks. The high NaCl diet elevated mean arterial pressure and greatly reduced basal norepinephrine metabolite levels in the anterior hypothalamic area of the spontaneously hypertensive (but not the control) rats (305 +/- 32 pg/10 min in the rats consuming 1% NaCl and 93 +/- 9 pg/10 min in the rats consuming 8% NaCl). An infusion of tramazoline (an imidizoline that causes long-lasting hypertension) that increased arterial pressure by 25 mm Hg elevated anterior hypothalamic area norepinephrine metabolite concentrations significantly more in the spontaneously hypertensive rats on the 1% NaCl diet (to 392 +/- 46 pg/10 min) than in those on the 8% NaCl diet (to 113 +/- 18 pg/10 min). In contrast, in Wistar-Kyoto rats the tramazoline-induced increase in arterial pressure elevated anterior hypothalamic area norepinephrine metabolite concentrations slightly more in rats on the 8% NaCl diet than in those on the 1% NaCl diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Initial Medication Selection For Treatment Of High Blood Pressure

Abstract: In this issue of JABFP, Jerome, et al. l report on a study in which they utilized paid claims data from an open-panel health maintenance organization (HMO) in the midwestern United States to determine prescribing patterns for antihypertensive therapy of patients with newly diagnosed disease. They found that most patients received monotherapy, with a minority receiving either stepped care or sequential monotherapy. Calcium channel blockers and angiotensin-converting enzyme (ACE) inhibitors were used most frequently as initial mono therapy, and treatment did not appear to be customized for comorbid conditions. The authors concluded that costs for treating hypertension could be reduced and care improved if thiazide diuretics, combination potassium-sparing thiazide diuretics, or ~-blockers were used more frequently as initial monotherapy. In choosing calcium channel blockers and ACE inhibitors most often as initial monotherapy for essential hypertension, the physicians in this HMO are consistent with current prescribing practices in the United States, where calcium channel blockers are the most widely prescribed and ACE inhibitors are the second most widely prescribed drugs for hypertension. These prescribing patterns prevail even though expert panels in the United States,2 Canada,3 Great Britain,4 and New Zealand5 have designated the diuretics (often along with ~-blockers) \"preferred\" therapy for hypertension. The World Health Organization International Society of Hypertension has made similar, but less emphatic, recommendations.6 The rationale for this recommendation is that diuretics and ~-blockers