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Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serotonin (5-hydroxytryptamine; 5HT) kinetics and platelet activation by 5HT were studied in patients with essential hypertension (n = 45), and in matched normotensive subjects (n = 45). Platelet response to 5HT and plasma beta-thromboglobulin increased with age in men, both normotensives and hypertensives. Beta-thromboglobulin and 5-hydroxyindoleacetic acid (5HIAA) excretion were higher in hypertensive men than in women. In women, no changes in platelet activity or 5HIAA excretion were found. 5HT plasma concentrations increased with blood pressure. Platelet 5HT uptake (Vmax and KM) were the lowest in hypertensive men greater than or equal to 60 years of age. This may indicate that 5HT uptake in vivo in normotensives is far below maximum (VNT much less than Vmax), whereas in hypertensive men it may be close to maximum (VHT approximately Vmax). This could reflect significantly higher 5HT plasma concentrations in vivo hypertensives than in normotensives. The reduced uptake (which was found only in hypertensive men) may indicate an insufficient compensation of the enhanced 5HT release from aggregating platelets in older men, in whom platelet activity is enhanced in vivo. It is concluded that the defect in platelet 5HT uptake in hypertensives--along with the enhanced platelet aggregation--may contribute to a critical increase in 5HT plasma concentrations locally. An increase in 5HT concentrations leads to biochemical changes (higher 5HIAA excretion) as well as to an enhanced stimulation by 5HT. This may be of clinical relevance especially in older men, in whom 5HT2-receptor mediated responses are enhanced.
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PMID:Impaired uptake of 5 hydroxytryptamine platelet in essential hypertension: clinical relevance. 170 94

Serotonin (5HT), discovered in the 1950s, has been the subject of renewed interest for several years, in particular due to the subdivision of 5HT receptors into various types. Concomitantly, several more or less selective agonists and antagonists for these various receptor subtypes have been developed. Although the physiologic relevance of 5HT remains largely unknown, its role in certain pathologic processes is widely accepted. Certain symptoms of the carcinoid syndrome, thromboembolic processes at the level of the microcirculation, and possibly also coronary spasm and peripheral vascular disease are likely to be associated, at least in part, with endogenous 5HT and serotonergic mechanisms. However, a primary and causative role for such mechanisms in essential hypertension seems unlikely. The blockade of peripheral 5HT2 receptors with drugs may offer advantages, in particular in those disorders where an interaction between predamaged blood vessels and platelets is involved. Such a therapeutic approach seems to be a more generally applicable principle than the lowering of blood pressure as such, which appears not to be a general phenomenon provoked by 5HT2-receptor blockade.
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PMID:The role of serotonin in cardiovascular diseases and their treatment. 208 Nov 37

A survey shall be given on the physiological, pathophysiological and pharmacotherapeutic backgrounds of the biogenic amine 5-hydroxytryptamine (serotonin; 5HT), to be preceded by a few historical remarks. 5HT is biosynthesized from L-tryptophan via hydroxylation and subsequent decarboxylation. 5HT is predominantly found in enterochromaffin cells, platelets and in various structures of the central nervous system. Its concentration in circulating blood is low and probably subthreshold. Whereas the physiological role of 5HT is rather unclear, 5HT appears to play a relevant role in certain psychiatric disorders, in migraine and the carcinoid syndrome. Its role in essential hypertension remains uncertain. However, 5HT appears to contribute to and to exacerbate the damage to blood vessels which were already predamaged by atherosclerosis, diabetes mellitus or possibly old age as such. A major breakthrough in the pharmacology of the serotonergic system was achieved by the discovery of several subtypes of 5HT receptors, with a corresponding collection of selective agonists and antagonists towards these receptor subtypes. This development is the basis of various drugs which interact with the serotonergic system and its receptors, like the various 5HT2 receptor antagonists (of which ketanserin is the prototype), methysergide, pizotifen, urapidil, flesinoxan and a variety of psychoactive drugs. The most important of these drugs and their potential application will be discussed with an emphasis on cardiovascular disorders.
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PMID:Pathophysiological and pharmacotherapeutic aspects of serotonin and serotonergic drugs. 213 70

To investigate possible alterations in 5-hydroxytryptamine (5HT) kinetics and sensitivity of blood platelets in patients with essential hypertension, 45 essential hypertensive patients and 45 normotensive healthy subjects matched in pairs for age, sex, and smoking status were compared. There were 18 women and 27 men in each group, ranging from 30 to 73 years of age. Results of essential hypertensive patients differed in several ways from those of normotensive subjects. In essential hypertensive patients, maximal 5HT uptake velocity (Vmax) decreased with increasing blood pressure and age and was reduced the most in older men. Vmax was positively related to the EC50 of 5HT for inducing a shape change reaction. In essential hypertensive patients, both Vmax of 5HT uptake and the EC50 of 5HT for shape change showed positive correlations with the 5HT content in platelets; the former relation was different between the essential hypertensive and normotensive groups (F = 5.53; p = 0.02). These results indicate reduced uptake of 5HT by blood platelets and suggest enhanced 5HT plasma concentrations in local areas, especially vascular lesions in essential hypertensive patients. Increased periplatelet concentrations of 5HT may lead to preactivation of platelets and possibly stimulation of vascular smooth muscle via their 5HT2-receptors. These changes are likely to be involved in the pathogenesis of increased thromboembolic complications in essential hypertensive patients, particularly in older men.
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PMID:5-Hydroxytryptamine kinetics and activation of blood platelets in patients with essential hypertension. 213 32

In a cross-over study, the effect of 25 mg urapidil infusion (U, Ebrantil 25, Byk-Gulden, FRG) on serotonin (5HT) metabolism and platelet aggregation (PA) was compared with the effect of placebo (P) in 7 patients with essential hypertension. No changes in 5HT and 5-hydroxyindolacetic acid (5HIAA) plasma levels and platelet 5HT content were observed. PA induced ex vivo by ADP decreased significantly. 5HIAA urinary excretion and fractional excretion (FE) increased, while 5HT renal metabolism changed only moderately. No changes in adrenaline and noradrenaline excretion were observed. In in vitro studies, U in therapeutic levels decreased ADP-induced PA and completely inhibited 5HT-induced PA (platelets of healthy volunteers). It is suggested that U has a direct antiaggregatory effect through 5HT2 receptors of platelets.
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PMID:Acute effect of urapidil on peripheral serotonin metabolism. 222 76

Serotonin (5HT) released from activated platelets causes platelet aggregation and vasoconstriction which are both exaggerated in older age and contribute to the development of thromboembolic complications. Platelet 5HT kinetics and reactivity were investigated in 45 patients with essential hypertension and 45 healthy control subjects matched for age, sex and smoking status. An age-dependent attenuation of total 5HT turnover and platelet 5HT release was revealed in control subjects but not in patients with essential hypertension. In the latter, especially in men, platelet 5HT uptake decreased with age and high blood pressure, leading to elevated 5HT plasma concentration. In parallel, platelet reactivity was increased with advancing age as shown by a greater 5HT induced aggregation and higher beta-thromboglobulin plasma concentration. Antihypertensive treatment with ketanserin resulted in inhibition of 5HT-induced shape change reaction and aggregation as well as a decrease in platelet 5HT release. Age contributes to altered platelet 5HT kinetics and 5HT2-receptor reactivity thereby elevating thromboembolic risk. 5HT2-receptor blockade with ketanserin interferes with these events by inhibition of platelet 5HT release and by a greater antiaggregatory and antihypertensive action in older age.
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PMID:Age, platelet serotonin kinetics and 5HT2-receptor blockade in essential hypertension. 225 91

Platelet derived serotonin (5HT) contributes to blood pressure elevation and the development of thromboembolic complications. Among the pathophysiological mechanisms involved in these vascular events, derangements in 5HT kinetics and exaggerated platelet response to 5HT may be part of the major triggering factors. An age-dependent attenuation platelet 5HT kinetics was revealed in normotensive control subjects but not in patients with essential hypertension. In older hypertensive patients, particularly in men, platelet 5HT uptake was decreased. In parallel, platelet reactivity was increased with advancing age as shown by a greater 5HT induced platelet aggregation and higher plasma concentration of beta-thromboglobulin. Antihypertensive treatment with the 5HT2-receptor antagonist ketanserin attenuated platelet 5HT turnover and inhibited 5HT induced platelet aggregation; the latter was more pronounced in older patients. The clinical efficacy and tolerability of ketanserin 20-40 mg twice daily given as mono- or combination therapy was evaluated in 188 patients with mild to moderate essential hypertension for a period of 12 weeks. A greater fraction of patients greater than or equal to 60 years achieved diastolic target pressure of less than or equal to 95 mgHg. Complaints related to the central nervous system or the peripheral circulation were greatly reduced in patients older than 60 years. In older patients, over and above the antihypertensive effect, 5HT2-receptor blockade may play an important role in the prevention of thromboembolic complications by inhibition of 5HT induced platelet activation.
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PMID:Age and 5HT 2-receptor blockade with ketanserin in essential hypertension. 269 21

The antihypertensive efficacy and tolerability of the 5HT2-receptor antagonist ketanserin was investigated in 188 patients aged 41 to 82 years with mild to moderate essential hypertension. Ketanserin was given as monotherapy (n = 107) as well as in combination with either the diuretic hydrochlorothiazide/amiloride (n = 42) or the betablocker atenolol (n = 39) for 12 weeks. Compared to placebo, ketanserin lowered systolic blood pressure by 11 +/- 16 (SD), 9 +/- 13 and 9 +/- 11 mm Hg (p less than 0.01 for all) and diastolic blood pressure by 9 +/- 10, 10 +/- 9 and 7 +/- 9 mm Hg (p less than 0.001 for all), in the three treatment groups; body weight, serum sodium, potassium, uric acid, cholesterol and triglycerides remained unchanged. The incidence of withdrawals due to unwanted effects was 4% on ketanserin monotherapy, and 12% and 10% on the diuretic/ketanserin and the betablocker/ketanserin combination respectively. Well-being during ketanserin therapy was improved in the older patients in particular; sleep disturbances, daytime fatigue and overall weakness decreased. Ketanserin was well tolerated in combination with the diuretic, whereas in combination with the betablocker the occurrence of dry mouth and stuffy nose was slightly higher. - Ketanserin proved to be an effective antihypertensive drug comparable to other blood pressure lowering agents. It can be combined advantageously with a potassium sparing diuretic or a betablocker. The greater efficacy and tolerability in patients greater than or equal to 60 years qualify ketanserin primarily as an antihypertensive agent for older patients.
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PMID:[Blood pressure lowering action and tolerance of ketanserin in mono- or combination therapy]. 271 Nov 55

Serotonin (5HT) has been implicated in thromboembolic complications and blood pressure elevation and both may be reduced with the 5HT2-receptor blocker ketanserin. In 17 patients with essential hypertension (WHO I and II, diastolic pressure V greater than or equal to 100 mmHg) blood pressure, platelet 5HT uptake, content and release as well as 5HT-induced shape change and aggregation were measured before and immediately after 8 weeks oral ketanserin at 20-40 mg twice daily. During ketanserin therapy, platelet 5HT release, shape change reaction and aggregation to 5HT were significantly reduced by more than 50%. These platelet effects were more pronounced in patients responsive to ketanserin (greater than or equal to 10% decrease of diastolic pretreatment pressure) and the fall in diastolic pressure correlated with the inhibition of 5HT-induced aggregation as well as the change in 5-hydroxy-indoleacetic acid (5HIAA) in platelet-rich plasma (PRP; P less than 0.05). Serotonin-receptor-independent platelet events were not affected by ketanserin. Ketanserin corrects 5HT2-receptor-mediated platelet function along with the reduction of blood pressure.
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PMID:Platelet deactivation by 5HT2-receptor blockade parallels the antihypertensive response to ketanserin. 272 27

The role of serotonin in the pathogenesis of hypertension is interesting, and its investigation is much in vogue at present. This study compared the hypotensive effect of ketanserin, a specific 5-hydroxytryptamine receptor antagonist, with metoprolol in essential hypertension. On a double-blind basis, one treatment group (19 patients on ketanserin) was compared with another (21 patients on metoprolol). There was a significant reduction in diastolic blood pressure with both ketanserin and metoprolol (P less than 0,001). Side-effects were insignificant. One patient on metoprolol and 2 on ketanserin complained of dizziness. The dose of ketanserin was 40 mg twice a day and that of metoprolol 100 mg twice a day. Ketanserin does not appear to cause abnormal haematological values or biochemical adverse effects. It can be given to hypertensive patients with cardiac failure or bronchial asthma without adverse effects and may improve the peripheral vascular status of a hypertensive patient.
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PMID:A comparative study of ketanserin and metoprolol in essential hypertension. 293 40


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