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

The hypertension induced in adult male rats by doca/salt was found to be accompanied by a significant rise in whole brain tyrosine hydroxylase (TH) activity. A smaller hypertensive effect, produced by angiotensin (750 ng kg-1 daily) was also accompanied by a proportional rise in whole brain TH activity. The specific antagonists spironolactone and saralasin completely blocked both responses in the doca/salt- and angiotensin-treated animals respectively and spironolactone showed a partial inhibition of the effects of angiotensin. In all the animals treated there was a clear correlation between systolic blood pressure and whole brain TH activity. The significance of these changes is discussed in the light of the central mechanism of hypertension.
 ...
PMID:Brain tyrosine hydroxylase activity and systolic blood pressure in rats treated with either deoxycorticosterone and salt or angiotensin. 0 9

1. Activity of peripheral and central catecholaminergic neurons was studied in spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats. 2. In young SHR (4 weeks) the plasma values of bpth noradrenaline and dopamine-beta-hydroxylase activity were increased compared with those of normotensive rats of the Wistar/Kyoto strain. Total catecholamines (mostly adrenaline) were not significantly different. 3. In the adrenal glands of 2-weeks-old and 4-weeks-old SHR activities of tyrosine hydroxylase, dopamine-beta-hydroxylase, phenylethanolamine-N-methyl transferase were decreased, compared to Wistar/Kyoto rats. 4. The adrenaline-forming enzyme was elevated in the A1 and A2 regions of the brain stem of 4-weeks-old SHR and in the A1 region of adult DOCA-salt hypertensive rats. 5. In the adrenal glands of adult DOCA-salt hypertensive rats tyrosine hydroxylase activity was increased. 6. These results implicate peripheral noradrenaline-containing neurons and central adrenaline-containing neurons in the development of genetic and experimental hypertension in rats.
 ...
PMID:Peripheral and central catecholaminergic neurons in genetic and experimental hypertension in rats. 1 56

A 12-year-old boy with a norepinephrine-secreting pheochromocytoma that caused hypertension resistant to oral alpha adrenergic blockade is reported. Resistance to alpha adrenergic blocking agents developed when the patient's daily propranolol dosage was lowered from 10 to 1 mg/kg. Subsequently, alpha methyl tyrosine, an inhibitor of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, controlled the patient's blood pressure and was associated with reduction in total urinary catecholamine excretion. Norepinephrine content of the tumor and uninvolved adrenal gland removal at surgery was reduced. These findings confirm that alpha methyl tyrosine inhibited in vivo synthesis of catecholamines.
 ...
PMID:Childhood pheochromocytoma: treatment with alpha methyl tyrosine for resistant hypertension. 1 59

The activities of monoamine biosynthetic enzymes were measured in brain regions of several hypertensive rat models at various ages. The types of hypertensive rats were the spontaneously hypertensive rat (SHR) and a stroke-prone substrain of the SHR as well as DOCA-salt and renal hypertensive rats. The genetically hypertensive rats had significantly elevated blood pressures as compared to the Wistar-Kyoto control rat after 5 weeks of age. During the early development of hypertension in the SHR, the activities of tyrosine hydroxylase in the hypothalamus and corpus striatum and of dopamine-beta-hydroxylase in the hypothalamus and pons-medulla were significantly higher than in the control rats. Tryptophan-hydroxylase was also elevated in the hypothalamus in SHR. From 3 to 8 weeks of age there appeared to be a significant correlation between hypothalamic dopamine-beta-hydroxylase activity and blood pressure in the hypertensive rats. In contrast, the activities of tyrosine hydroxylase and dopamine-beta-hydroxylase were slightly decreased in the DOCA-salt and renal hypertensive rats. It is suggested that noradrenergic or adrenergic neurons in the hypothalamus may participate in the initiation of elevated blood pressure in the genetic, but not in the DOCA-salt or renal hypertensive rats.
 ...
PMID:Regional changes in the activities of aminergic biosynthetic enzymes in the brains of hypertensive rats. 1 54

In young, spontaneously hypertensive rats (SHR), a preganglionic, nerve-dependent, elevation of choline acetyltransferase (ChAc) and tyrosine hydroxylase (TH) activities was found in celiac ganglia as compared with those in young, normotensive Kyoto Wistar rats, that was not present in superior cervical ganglia, stellate ganglia and adrenal glands. The rise in both enzyme activities in the celiac ganglion disappeared in adult SHR. An elevation of plasma norepinephrine and dopamine beta-hydroxylase levels found in prehypertensive SHR, a probable indication of peripheral sympathetic activation, disappeared after the bilateral removal of the celiac ganglion. However, ganglionectomy did not change the subsequent development of hypertension. These results indicate that the faster maturation of the celiac ganglion and the end organs it innervates in yount SHR are causally related to the activation of the peripheral sympathetic nervous system. The peripheral sympathetic activation in young SHR is regarded as a warning sign but this does not trigger the development of hypertension.
 ...
PMID:Enhanced sympathetic activity in young spontaneously hypertensive rats is not the trigger mechanism for genetic hypertension. 2 May 86

Dopamine-beta-hydroxylase (DBH) activity in serum, DBH and tyrosine hydroxylase (TH) activities in mesenteric vessels, and DBH and TH activities in locus coeruleus and hypothalamus of brain did not differ significantly between spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKR) at 16 weeks of age when hypertension of SHR was fixed. In contrast, DBH and TH activities in vas deferens and adrenal glands were significantly higher in SHR than in WKR. These changes in SHR at 16 weeks of age after establishment of hypertension are directly opposite those reported previously in SHR at 3 weeks of age before the onset of hypertension.
 ...
PMID:Norepinephrine-synthesizing enzymes in brain, adrenals and peripheral sympathetic nerves of spontaneously hypertensive rats. 2 83

By repeated inbreeding, 2 strains of spontaneously hypertensive and normotensive rats have been simultaneously selected. The activities of tyrosine hydroxylase and phenylethanolamine-N-methyltransferase were determined in various central catecholaminergic nuclei (C1, C2, A6 and A9) and in two peripheral tissues (adrenal glands and superior cervical ganglion). These assays were performed on rats belonging to the normotensive or the hypertensive strain at 3 ages which characterize the development of hypertension (5, 9 and 21 weeks). Except for a decrease in the C1 region of 9-week-old rats, no significant change in tyrosine hydroxylase activity occurred in central or peripheral structures of the spontaneously hypertensive rats when compared to the normotensive rats. In contrast, the activity of the phenylethanolamine-N-methyltransferase (PNMT), was increased in the C2 adrenergic group of the medulla oblongata in young spontaneously hypertensive rats: +43% (P less than 0.001) at 5 weeks of age and +32% (P less than 0.001) in 9-week-old rats. However, there was no significant difference between the 21-week-old rats. No modification of the PNMT activity was found in the C1 adrenergic group of the medulla oblongata. PNMT activity was increased significantly in the adrenal glands of 5-week-old hypertensive rats (+22%, P less than 0.001). By 9 weeks, the difference in PNMT activity in the adrenals was no longer significant. Thus, in young rats of the hypertensive strain, there was an increase in the capacity to synthetize adrenaline in the C2 area of the medulla oblongata and in the adrenal glands. While the enzymatic change present in the adrenals seems to be specific to this new strain of hypertensive rats, the elevation of PNMT activity in a specific region of the medulla oblongata (C2 group) is a characteristic common to at least two independently derived strains of genetically hypertensive rats.
 ...
PMID:Early increase in phenylethanolamine-N-methyltransferase activity in a new strain of spontaneously hypertensive rats. 3 64

1. Noradrenaline content of several rat brain stem and hypothalamic nuclei falls transiently at 72 h after initiation of renovascular hypertension (one-kidney Goldblatt model). 2. Tyrosine hydroxylase activity is significantly reduced in posterior, paraventricular and periventricular nuclei of hypothalamus at this time but returns to control value by 7 days. 3. Treatment with hydrallazine, 5 mg/kg intraperitoneally, twice daily or methaoxamine, 5 mg/kg, three times daily for 3 days respectively raises and lowers the noradrenaline content of brain nuclei, suggesting that short-term changes in noradrenaline may be secondary to afferent baroreceptor input. 4. At later times after the development of renovascular hypertension (7 and 28 days) activity of phenylethanolamine-N-methyl transferase is increased in the nucleus of the solitary tract and the locus coeruleus. 5. Brain catecholamines may participate both early in the development and later in the maintenance of renovascular hypertension.
 ...
PMID:Brain catecholamines and catecholamine-synthesizing enzymes in renovascular hypertension in the rat. 3 99

1. Hypertension was induced in rats by renal artery clip with the contralateral kidney removed (Goldblatt I) or left intact (Goldblatt II). 2. Plasma noradrenaline was increased 62% in the Goldblatt I animals after 3 weeks. 3. Hypothalamic tyrosine hydroxylase and dopamine beta-hydroxylase activities, and the concentration of noradrenaline were increased in the Goldblatt I animals after 3 weeks. 4. Enhanced hypothalamic noradrenaline synthesis may be a pathogenic factor in Goldblatt I renovascular hypertension.
 ...
PMID:Enhanced hypothalamic noradrenaline biosynthesis in Goldblatt I renovascular hypertension. 3

The activities of tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT) have been measured in brain stem and hypothalamic nuclei during the development of renovascular hypertension. TH activity fell at 72 h in the posterior hypothalamic and peri- and paraventricular nuclei of the hypothalamus, but had returned to control levels by 7 days. PNMT activity was raised in the nucleus of the solitary tract at 7 days and was also elevated in the nucleus of the solitary tract, parahypoglossal nucleus, locus coeruleus and cerebellar cortex at 4 weeks. No change in PNMT was noted in hypothalamus. It appears from these results that both central noradrenergic and adrenergic pathways are involved in the development of this model of experimental hypertension.
 ...
PMID:Catecholamine synthesizing enzymes in brain stem and hypothalamus during the development of renovascular hypertension. 3 65


1 2 3 4 5 6 7 8 9 10 Next >>