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)

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.
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PMID:Enhanced sympathetic activity in young spontaneously hypertensive rats is not the trigger mechanism for genetic hypertension. 2 May 86

The decrease of sympathetic activity by the beta-blocking drug, as demonstrated by the decreased electric activity of the splanchnic nerve and by the decreased urinary catecholamine reponse to tilt as well as by the decreased levels of plasma dopamine beta-hydroxylase exists not only in hypertension with elevated PRA but also in hypertension with normal or low PRA. In these latter cases the antihypertensive effect is better explained by the decrease in the sympathetic nervous system activity than by the decrease of PRA. This effect seems to be indirect and probably, as suggested by Lewis, as a result of damping sensory input to the central nervous system from the heart, whose capacity to respond to exercice and stress is blunted by beta-adreno-receptor blockade.
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PMID:[The sympathetic nervous system inhibition in the antihypertensive effect of beta-blockers (author's transl)]. 2 20

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.
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PMID:Enhanced hypothalamic noradrenaline biosynthesis in Goldblatt I renovascular hypertension. 3

Knowledge of the vesicular origin of circulating dopamine beta-hydroxylase (DbetaH) is indispensable for any attempts to explain the parallelism or lack of it between circulating enzyme and catecholamines as they may relate to physiological stress, forms of hypertension, neurological disorders, and the response to pharmacological agents. The present study represents an effort to evaluate and to place in proper perspective data based on the DbetaH activity found in the region of the light vesicle peak of noradrenaline (NA), which is used as a quantitative measure of a population of small terminal vesicles. Distributions of vesicles and subvesicular components are compared with DbetaH and NA in sucrose-D2O density gradients used to prepare relatively pure fractions of large dense cored vesicles (LDV) from bovine splenic nerve. Although NA in sedimentable particles of the light vesicle peak is likely to be a valid measure of a small vesicle population, the following is demonstrated: (1) A substantial fraction (25%-37%) of the total sedimentable DbetaH activity can be proven to distribute in the region of the light vesicle peak from a tissue with an insignificant small vesicle population. Based on studies of vesicles from sequential nerve segments, this enzyme activity probably corresponds to a population of "immature" LDV which are undergoing axoplasmic transport and have not synthesized their full complement of transmitter. (2) Physical lysis which depletes the matrix of LDV causes redistribution of DbetaH activity from the heavy vesicle peak into the region of the light vesicle peak. Analogously, DbetaH associated with exocytosed LDV and retrograde transport particles is also likely to contaminate the region of the light vesicle peak. (3) Based on available data, it can be calculated that each small dense cored vesicle could contain only 0.1-0.5 molecules of DbetaH and that a contamination of only 0.016% LDV can account for all of the DbetaH reported to occur in the light vesicle peak of normal rat vas deferens preparations.
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PMID:Dopamine beta-hydroxylase distribution in density gradients: physiological and artefactual implications. 45 40

Racial differences in prevalence of essential hypertension are well known. In order to explore these differences at an early age in terms of etiology, we investigated schoolchildren in an entire, biracial community. A sample of 278 children, stratified by diastolic (fourth-phase) blood pressure and specific for age, race, and sex, was reexamined 1--2 yr after initial observation for the following: (1) a physical examination and urinalysis to exclude secondary hypertension; (2) 24-hr urine sodium, potassium, plasma renin activity, and serum dopamine beta-hydroxylase; (3) 1-hr oral glucose tolerance test; and (4) heart rate and blood pressure at rest and under standarized physical stress. We found that 24-hr urine sodium was positively associated with blood pressure level as measured on the same day for the high blood pressure strata of black children. Urine potassium excretion was lower in blacks than in whites, although their intakes seemed equal. In the high blood pressure strata especially, black boys had lower renin activity than whites, and the resting-supine and stressed systolic blood pressures were higher in black boys than in any other group. In these black boys, resting and stressed systolic pressures were negatively related to plasma renin activity. On the other hand, dopamine beta-hydroxylase levels in white children were higher than in blacks for all blood pressure strata, and in the high blood pressure strata white children had higher 1-hr glucose levels and faster resting heart rates than black children. Different mechanisms may play a role in and contribute to the early stage of essential hypertension.
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PMID:Racial differences of parameters associated with blood pressure levels in children--the Bogalusa heart study. 51 82

The relation of plasma dopamine beta-hydroxylase (DBH) activity to age was examined in normotensive and hypertensive subjects. Plasma DBH activity was the highest in the group of 25--34 years and gradually decreased with age. Plasma DBH activity was higher in the hypertensives than in the normotensives in all age groups, and the difference was significant between the groups of 45--54 and 55--64 years. Plasma DBH activity was increased in labile hypertension. Plasma DBH activity was higher in the group of essential hypertension with normal renal function than in that with reduced renal function. It was lower in the severe hypertensives than in the mild cases. Plasma DBH activity was also decreased in the hypertensive patients with cerebrovascular disorders. Plasma DBH activity was lower in the hypertensive patients with renal parenchymal diseases than those of essential hypertension with normal renal function. Plasma DBH activity was also decreased in primary aldosteronism, while it was increased in pheochromocytoma. These observations suggest that measurement of plasma DBH activity may be valuable in the differentiation of essential hypertension from the secondary forms of hypertension, and the evaluation of the hypertensive processes. To evaluate plasma DBH activity, it is important to consider its age-related changes.
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PMID:The evaluation of plasma dopamine beta-hydroxylase activity in essential and secondary hypertension. 57 40

In young spontaneously hypertensive rats (SHR), dopamine beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) activities were examined in the brainstem nuclei. Activation of noradrenergic neurons in the locus coeruleus, A2 and spinal intermediolateral cell areas, resulting in enhanced sympathetic nervous activity in the periphery, initiates hypertension. Adrenergic neurons, unchanged in these and A1 cell areas of young SHR, are not involved in the development of hypertension in SHR.
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PMID:Selective activation of noradrenergic neurons in the brainstem and spinal cord of young spontaneously hypertensive rats. 70 20

1. Plasma noradrenaline concentrations and dopamine beta-hydroxylase activity have been measured at various stages in the development of hypertension in the one-kidney Goldblatt rat (unilateral renal arterial constriction and contralateral nephrectomy). 2. Although plasma noradrenaline concentrations were significantly elevated from control values at 7, 14 and 28 days, plasma dopamine beta-hydroxylase activity was not significantly different from control values except at 24 h. 3. These findings suggest that peripheral sympathetic activity is increased in the one-kidney Goldblatt model of experimental hypertension but that plasma dopamine beta-hydroxylase activity is poor index of this increase. 4. Both the rise in blood pressure and the rise in plasma noradrenaline concentrations were prevented by pretreatment with intracisternal 6-hydroxydopamine, suggesting that the increased sympathetic activity is at least in part centrally mediated.
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PMID:Plasma noradrenaline concentrations in experimental renovascular hypertension in the rat. 86 41

The cardiovascular effects of a new antihypertensive drug, bupicomide, were compared with those of hydralazine in 6 patients with mild to moderate hypertension. The mean supine arterial pressure of patients was reduced 15.2 mm Hg by bupicomide (900 to 2,000 mg/day) and 15.7 mm Hg by hydralazine (300 to 600 mg/day). Heart rate increased an average of 11.3 bpm during bupicomide and 14.5 bpm by hydralazine. Neither drug was associated with a postural decrease in mean arterial pressure. The heart rate response during maximum tolerated treadmill exercise was not diminished by either drug. Cardiac index was increased during administration of both drugs. Bupicomide and hydralazine reduced forearm vascular resistance, while renal blood flow and renal vascular resistance were not significantly modified. Evidence of equivalent augmentation of sympathetic nervous activity during administration of both drugs consisted of equal and significant increases in heart rate and urinary norepinephrine excretion, and decreases in duration of the pre-ejection period. The absolute values of these parameters were correlated with mean arterial pressure, which may indicate that the increase in sympathetic nervous activity was mediated by baroreceptor reflexes. Although bupicomide inhibits dopamine beta-hydroxylase, our results suggest that it is acting as a direct vasodilator.
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PMID:Antihypertensive effect of a dopamine beta hydroxylase inhibitor, bupicomide: a comparison with hydralazine. 109 50

Serum dopamine beta-hydroxylase (DBH) activity was comparable in eight adrenalectomized patients and in 41 normal volunteers (37.8 +/- 3.6 vs. 40.0 +/- 4.0 IU), but were very low in four patients with severe diabetic autonomic neuropathy (6.7 +/- 4.2). These observations suggest that the major source of DBH activity in human serum is probably the sympathetic nervous system. Serum DBH activity was also significantly lower in seven patients with low renin essential hypertension than in 17 patients with normal renin hypertension (19.9 +/- 4.3 vs. 43.9 +/- 5.0 IU, P less than 0.05). Dietary sodium depletion, a stimulus for catecholamine secretion, produced only a small increase in serum DBH activity in supine normal volunteers (26.5 +/- 10.4 to 33.9 +/- 11.4, P less than 0.05; n = 7) and in five adrenalectomized patients (33.0 +/- 12.7 to 44.1 +/- 15.2, P = 0.06). Plasma renin activity increased more than 3-fold in these same subjects, and did not correlate with serum DBH activity. Similarly, 4 hours of ambulation produced only a small increase in serum DBH activity which did not correlate with plasma renin activity. The small magnitude of these responses to physiological stimuli of the sympathetic nervous system diminishes the potential clinical usefulness of measurement of serum DBH activity. Further studies utilizing direct correlation of plasma and urine catecholamines with serum DBH activity are needed to establish its relationship to sympathetic nervous system activity.
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PMID:Serum dopamine beta-hydroxylase as an index of sympathetic nervous system activity in man. 124 23


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