Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Labile hypertension in patients under 50 years of age (the non-atherosclerotic form) was found to be characterized by higher urinary excretion of catecholamines and particularly of homovanillic acid; when further analyzed it was shown to be a heterogeneous entity with two types of patients clinically and biochemically distinguishable from each other, from control subjects and from patients with stable hypertension. Reactivity to assuming an upright posture distinguishes one type of labile hypertension having a normal postural pulse rate response from another having an excessive postural increase in pulse rate. The first group also showed normal responses of plasma norepinephrine concentration and of urinary cyclic AMP to posture. The group with excessive pulse rate response, in contrast, showed a decrease in plasma norepinephrine and an excessive increase of urinary cyclic AMP excretion in response to upright posture. The results suggest that not only circulating catecholamines but also the reactivity of their target tissues (as probably reflected by cyclic AMP measurements) are important in bringing about signs of adrenergic excess. The hypothesis that cyclic AMP changes reflect beta-adrenergic receptor reactivity is strongly favoured by data indicating qualitative differences in cyclic AMP responses to beta-adrenergic stimulation or inhibition between control subjects and those labile hypertensive patients with clinical signs of excessive sympathetic reactivity. The study stresses the need for more precise definition of labile hypertension, for dynamic clinical and biochemical correlative studies, and for consideration not only of the circulating hormones but also of the "second messengers" (such as cyclic AMP and cyclic GMP) which reflect the cellular action of hormones. Blood pressure is a very labile parameter in health and disease. In one sense, therefore, hypertension can be considered "labile" in every hypertensive patient. Usually, however, labile (or borderline) hypertension is regarded as characterized by a blood pressure over 140/90 mmHg, falling below these values with physical and emotional rest. This clinical entity, which affects some 20% (variously estimated between 16 and 30%) of the adult population, gives rise to uncertainties in both definition and prognosis. In some patients labile hypertension represents the precursor of a fixed hypertensive state, whereas in many others it remains labile throughout life, never progressing to the stable phase nor becoming associated with hypertensive cardiovascular disease.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Labile (borderline) hypertension--new aspects of a common disorder. 23 54

Changes in cyclic nucleotide metabolism similar to those characteristic of the chronic forms of hypertension were observed in an acute neurogenic form of hypertension in rats produced by electrolytic lesions of the nucleus tractus solitarii. These changes that were evident 2 hr after the lesions were made included decreased cyclic AMP levels in the heart, increased cGMP:cAMP ratio, cAMP phosphodiesterase (3':5'-cAMP 5'-nucleotidohydrolase, EC 3.1.4.17) and guanylyl cyclase (GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2) activities in the aorta and decreased snesitivity of adenylyl cyclase (ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1) in both the aorta and heart to stimulation by the beta-adrenergic stimulant isoproterenol. These changes appear to depend on catecholamine release and are not due to mechanical distortion secondary to the increased arterial pressure. These studies provide biochemical support to the concept that the sympathetic nervous system may play a critical role in the initiation of the hypertensive syndrome and that chronic hypertension could result from the fixation of the biochemical effects of increased sympathetic activity.
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PMID:Changes in cyclic nucleotide metabolism in aorta and heart of neurogenically hypertensive rats: possible trigger mechanism of hypertension. 23 70

Angiotensin II (Ang II) inhibits renin secretion and production from the kidney, but the effect of Ang II on adrenal renin is not clear. Nephrectomy, via elevated plasma adrenocorticotropic hormone (ACTH) and potassium, is a strong stimulator of adrenal renin production in the rat. This stimulation is inhibited by the infusion of Ang II, suggesting a negative feedback between Ang II and adrenal renin. In the present study, we examined the effect of Ang II on adrenal renin using a primary culture of rat glomerulosa cells. Cells were exposed to ACTH (10(-11) M), high potassium (8 and 12 mM), db-cyclic AMP (db-cAMP), (10(-3) M), or Ang II (10(-11) to 10(-5) M) for 24 hours, and active renin and inactive renin were measured. Active renin was predominant in the cells, whereas inactive renin predominated in the medium. Ang II stimulated renin production in a dose-dependent fashion (cell-active renin, 1.21 +/- 0.20 to 2.39 +/- 0.16; medium-inactive renin, 2.59 +/- 0.40 to 6.14 +/- 0.49 ng Ang I/10(6) cells). Both ACTH and db-cAMP significantly stimulated active renin in the cells (ACTH, 1.73 +/- 0.14 to 9.44 +/- 0.98; db-cAMP, 1.45 +/- 0.16 to 3.96 +/- 0.71 ng Ang I/10(6) cells) and inactive renin in the medium (ACTH, 4.98 +/- 0.38 to 43.7 +/- 5.63; db-cAMP, 3.80 +/- 0.32 to 33.55 +/- 5.62 ng Ang I/10(6) cells). The addition of Ang II (10(-7) M) blunted the stimulation of renin production by both ACTH and db-cAMP by 60%. High potassium-stimulated renin production was not inhibited by Ang II.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1992 Mar
PMID:Effect of angiotensin II on renin production by rat adrenal glomerulosa cells in culture. 131 12

In order to elucidate the influence of acute ocular inflammation on the aqueous humor dynamics and intraocular pressure (IOP), we carried out argon laser photo-coagulations on the rabbit irises and determined the concentrations of aqueous humor prostaglandins (PGs), cyclic AMP and protein. The IOP changed in a biphasic manner, i.e. initial hypertension and later hypotension. The concentrations of aqueous humor PG E2, PG F2 alpha and protein increased markedly after laser irradiation and then decreased gradually, although the concentrations of PG E2 and protein remained significantly higher than the baseline values at 24 hours after the irradiations. The concentrations of aqueous cyclic AMP of the irradiated eyes and control eyes were 67.8 pmol/ml and 29.3 pmol/ml, respectively. We presumed that the increase in concentration of aqueous cyclic AMP and breakdown of the blood-aqueous barrier by PGs caused the reactive hypotension.
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PMID:[Effects of argon laser irradiation of the iris on the concentration of aqueous prostaglandins and cyclic AMP]. 131 34

Hypercholesterolemia and hypertension are two of the major risk factors associated with increased atherosclerotic vascular disease. An abnormal platelet function is one of the mechanisms proposed to participate in atherogenesis. This study was undertaken to find out whether hypercholesterolemia in hypertensive patients can change platelet lipid composition and reactivity. Twenty-nine untreated hypertensive patients were distributed into 3 age, body mass index and blood pressure-matched groups according to their plasma cholesterol levels (normal, borderline or elevated, group NC, BC and HC respectively). Their platelet lipid composition, cytosolic Ca2+ concentration, cyclic AMP content and aggregating response to ADP and collagen were determined. Platelet from group HC patients were characterized by reduced cyclic AMP content (evaluated in the presence and absence of a platelet phosphodiesterase inhibitor) and aggregating responses to ADP and collagen, increased palmitic acid content and decreased arachidonic, eicosapentaenoic and docosatetraenoic and pentaenoic acid content, resulting in a lowered polyunsaturated to saturated fatty acid ratio (P less than 0.001). In contrast, platelet cytosolic Ca2+ concentration, DPH steady-state anisotropy and cholesterol to phospholipid molar ratio were not significantly changed. This indicates that hypercholesterolemia is accompanied in hypertensive patients by marked changes in platelet fatty acid composition, cyclic AMP content and response to aggregating agents. These changes, which clearly differ from those induced by in vitro cholesterol loading, could reflect not only the balance between LDL and HDL stimulation but also an adaptation to hemodynamic perturbations.
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PMID:Biochemical and functional alterations associated with hypercholesterolemia in platelets from hypertensive patients. 132 32

The effects of prostaglandin E2 (PGE2) infusions on lymphocyte beta 2-adrenoceptor-dependent adenylate cyclase (beta 2ARAC) system were studied in 26 patients with resistant hypertension (RH). The density of beta 2-adrenoceptors and their affinity for 1-isoproterenol were measured with 125ICYP and adenylate cyclase activity was determined by alpha-[32P]AMP generation in mononuclear lymphocytes of RH patients before and 1, 7, and 14 days after the last PGE2 infusion. Plasma epinephrine and norepinephrine concentrations were analyzed by using HPLC. The resistance to the four-component drug therapy was overcome with PGE2 infusions in patients, leading to a decrease in lymphocyte beta 2-adrenoceptor density and an increase in beta 2-receptor affinity for catecholamines and in adenylate cyclase activation by stimulating agents. PGE2 infusions unchanged the sensitivity to antihypertensive drugs in patients resulting in an increase in lymphocyte beta 2-adrenoceptor density, a decrease in beta 2-receptor affinity for catecholamines and in adenylate cyclase activation.
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PMID:[Regulation of the adenylate cyclase system of lymphocytes in patients with therapy-resistant arterial hypertension and during PGE2 administration]. 132 77

Exposure to vanadate was found to induce arterial hypertension through effects on renin-angiotensin-aldosterone, renal peptidergic, and central and peripheral catecholaminergic systems. Vanadate increased, mainly in vascular myocells, both receptor-operated Ca2+ channel- and cyclic-AMP-dependent availability of Ca2+ for contractile processes. Vanadate was selectively accumulated by tissues in the +4 oxidation state (vanadyl).
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PMID:Kallikrein-kinin,enkephalin, renin-aldosterone and catecholamine systems in the vanadate (as vanadyl)-induced arterial hypertension. 133 53

We isolated the human C-type natriuretic peptide gene and identified the peptide in the brain. The human C-type natriuretic peptide gene appeared to be composed of at least two exons and one intron. In the 5'-flanking region, there is an array of cis elements (an inverted CCAAT box, two GC boxes, and a cyclic AMP response element-like sequence) that is not present in upstream sequences of the atrial and brain natriuretic peptide genes. Analysis of the deduced amino acid sequence revealed that human prepro C-type natriuretic peptide comprises 126 amino acids and that the C-terminal 22-residue peptide (G-L-S-K-G-C-F-G-L-K-L-D-R-I-G-S-M-S-G-L-G-C) preceded by Lys-Lys is identical to the porcine counterpart. However, replacement of two amino acids took place in the C-terminal 53-residue sequence, corresponding to another endogenous form of the peptide. Reverse-phase high-performance liquid chromatography coupled with a radioimmunoassay for C-type natriuretic peptide demonstrated that it occurs in the human brain. C-type natriuretic peptide-like immunoreactivity was detected in discrete regions of the human brain, and its level was 10-fold higher than the atrial and brain natriuretic peptide levels, raising the possibility that C-type natriuretic peptide is the major natriuretic peptide in the human brain.
Hypertension 1992 Jun
PMID:Human C-type natriuretic peptide. Characterization of the gene and peptide. 133 2

1. The abilities of various serotonergic drugs to bind with the 5-HT receptor of Ascaris suum muscle and to affect cyclic AMP levels in muscle tissue were examined. 2. Ligands which selectively interact with either the 5-HT1 or the 5-HT2 receptor in mammalian systems interact with the 5-HT receptor from A. suum muscle and increase cyclic AMP levels. 3. No binding of 5-HT3 ligands to 5-HT receptors from A. suum muscle was observed. 4. The 5-HT receptor of A. suum muscle should be called the 5-HTN (for Nematoda) receptor because its pharmacological and biochemical behaviors were different from those of mammalian 5-HT receptors.
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PMID:Identification of a novel 5-HTN (Nematoda) receptor from Ascaris suum muscle. 135 23

Regulation of catecholamine biosynthesis is crucial in the adaptation to various physiological conditions, such as stress, and in several disorders, including hypertension and depression. In this study we have found that in PC12 cells, the mRNA levels of dopamine beta-hydroxylase (DBH), the enzyme that catalyzes the formation of norepinephrine from dopamine, can be regulated by glucocorticoids and cyclic AMP (cAMP) analogues. Treatment with dexamethasone increased DBH mRNA levels by 6 h. with maximal elevation (four- to fivefold) obtained after 1 day of exposure, and these levels were maintained for up to 4 days. DBH mRNA levels were also elevated on treatment of PC12 cells with 8-bromo cAMP for 8 h to 1 day. The response to 8-bromo cAMP, however, was bimodal, because DBH mRNA levels declined below control values on treatment for > 1 day. In combined treatments with 8-bromo cAMP and dexamethasone, the cAMP effect was dominant. To begin to characterize the regulation of DBH mRNA, genomic clones for rat DBH were isolated, and 1 kb of the 5' flanking region was sequenced. Several putative regulatory elements, which may be involved in cAMP and glucocorticoid regulation, were identified, including two adjacent cAMP response elements, another element that can also bind members of the ATF/CREB family of transcription factors, a NF-kappa B-like sequence, several AP-2 sites, and three core glucocorticoid receptor binding sequences.
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PMID:Regulation of expression of dopamine beta-hydroxylase in PC12 cells by glucocorticoids and cyclic AMP analogues. 135 11


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