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 concentrations of the vasoactive substance, 5-hydroxytryptamine (5-HT), were estimated in whole blood samples from 12 pregnant women with hypertension in the third trimester. These were compared with a control group of 15 normotensive pregnant women of the same gestation. The hypertensive patients were admitted for observation and the whole blood 5-HT estimated again after four days bed rest: in all patients the blood pressure had, by this time, returned to within the normal range. No significant difference was found between the mean blood 5-HT concentrations of the hypertensive and the normotensive groups. A small, but not statistically significant, rise occurred in the hypertensive group after four days bed rest. Thus this study gave no evidence that 5-HT is implicated in hypertension in pregnancy.
 ...
PMID:The possible relation between late pregnancy hypertension and 5-hydroxytryptamine levels in maternal blood. 46 98

Excitation of a cardiac chemoreceptor with 5-hydroxytryptamine (serotonin) produces a complex autonomic reflex which includes hypertension, changes in heart rate and contractile force, and disturbances of AV conduction. This study examines the afferent and efferent neural pathways of this autonomic reflex in 60 anesthetized dogs. We used cooling and sectioning techniques in 40 of these, and in 20 others recorded afferent neurograms. The most common afferent pathways for the reflex were found in the left and right recurrent cardiac nerves. No preferential efferent routes to the heart were found, although the nature of the reflex cardiac response could be altered by specific nerve interruption. Cyproheptadine (1 mg/kg iv) regularly abolished both the reflex and the chemoreceptor afferent neural traffic, but injection of a 10 times higher concentration of serotonin (1 mg/ml) readily surmounted the blockade and restored the chemoreceptor neural traffic. Thus cyproheptadine interdicts the reflex at the site of its initiation.
 ...
PMID:Neural pathways of a cardiogenic hypertensive chemoreflex. 69 46

Antihypertensive and diuretic effects of trichlormethiazide (TCM) were investigated in the spontaneously hypertensive rats (SHR). The antihypertensive effect of TCM in an acute experiment was observed in male SHR only at a dose over 10 mg/kg given intraperitoneally and not in female SHR and normotensive Kyoto Wistar rats. In a subacute experiment (6 weeks), TCM retarded the development of hypertension in the male SHR loaded with 1% saline solution at an oral dose over 1 mg kg-1 day-1 and such had a diuretic effect. Oral administration of TCM and hydrochlorothiazide (HCT) at 10 mg kg-1 day-1 retarded the development of hypertension in the saline loaded female SHR to the same degree, but the relationship between antihypertensive and diuretic effects of both compounds was obscure. Except for decreases of water contents in the thoracic artery and wet weights of hearts, the electrolyte, uric acid, catecholamine and 5-hydroxytryptamine contents in the serum or/and organs were not affected by either TCM or HCT. It is concluded that the antihypertensive effect of TCM and HCT can be observed in SHR with a saline-load, and that the effect may be due to diuretic actions in the male. The relationship was not apparent in female SHR.
 ...
PMID:Antihypertensive effect of trichlormethiazide in spontaneously hypertensive rats. 73 42

5-hydroxydopamine, unspecific centrally acting false neurotransmitter. Acta Physiol. Pol., 1977, 28 (1): 13-22. 3,4,5-trihydroxyphenetylamine-5-hydroxydopamine (5-OHDA) injected intracerebro-ventricularly decreases the level of noradrenaline, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in different parts of the rat brain. It does not affect acetylcholine level. 5-OHDA causes dose-dependent hypothermia, transient hypertension and depression of locomotor and exploratory activity in rats. This behavioral phenomena are reversed by central chemical sympathectomy elicited by 6-hydroxydopamine. It is concluded that 5-OHDA is an unspecific centrally acting false transmitter.
 ...
PMID:5-hydroxydopamine, unspecific centrally acting false neurotransmitter. 86 21

One hundred and forty-four human pineal glands obtained at necropsy were analysed for their content of catecholamines, indolealkylamines and calcium and the findings related to sex, age, terminal illness and medication. A preliminary study of 45 pineal organs revealed no significant differences in amine pattern in glands removed 6-48 hours post mortem. A statistically significant difference of pineal weight, calcium and amine content could not be detected in glands of age-matched groups of male and female patients who died suddenly without apparent clinical illness. A highly significant correlation between pineal weight and calcium content was established in patients older than 60 years. Considerable variability of amine levels existed in all groups of patients. Adrenaline as well as noradrenaline were detected in most glands. This finding was corroborated by the formation of radioactively labelled adrenaline from noradrenaline and 14C-S-adenosylmethionine by extracts from human pineals. Dopamine was most abundant in glands from patients dying of malignant tumours. The content of the indolealkylamines (5-hydroxytryptamine and melatonine) varied between a few nanograms to 21 mug/g tissue. The highest mean calcium content was detected in glands of patients who died of renal disease associated with hypertension.
 ...
PMID:Catecholamine, indolealkylamine and calcium levels of human pineal glands in various clinical conditions. 100 48

1. The effect of prolonged anti-hypertensive drug treatment on the blood pressure of conscious spontaneously hypertensive rats (SH-rats), and of age-matched normotensive Sprague-Dawley rats was determined during the development of hypertension in SH-rats and in the early stages of established hypertension. A comparison of the vascular reactivity to noradrenaline (NA) and 5-hydroxytryptamine (5-HT) was also made in isolated perfused mesenteric artery preparations from treated and control SH- and Sprague-Dawley rats. 2. Chronic treatment from age 4 to 16 weeks with hydrallazine alone, or a combination of hydrallazine/hydrochlorothiazide/reserpine, ad libitum in the drinking water, prevented the development of hypertension in SH-rats and also reduced the vascular reactivity to NA and 5-HT in isolated vessel preparations from treated compared to control rats. 3. Similar drug treatments started in early established hypertension reduced blood pressure in SH-rats over the 12 week treatment period (from age 8 to 20 weeks) without affecting vascular reactivity to NA and 5-HT in the isolated vessel preparation. 4. Drug treatments had little effect on blood pressure of age-matched Sprague-Dawley rats and no effect on vascular reactivity to NA and 5-HT in the isolated perfused mesenteric artery preparation from treated compared to control rats. 5. These results indicate that the development of increased vascular reactivity and of hypertension in SH-rats occurs simultaneously and, therefore, the vascular changes may be a consequence of the structural changes induced by the raised blood pressure. 6. In established hypertension, no regression of vascular changes was observed despite prolonged reduction of blood pressure. The role of an increased vascular reactivity in the maintenance of hypertension is therefore questionable.
 ...
PMID:Influence of anti-hypertensive drug treatment on vascular reactivity in spontaneously hypertensive rats. 117 60

To investigate if there can be alterations in the 5-hydroxytryptamine (5-HT) uptake system in the sensitivity of platelets in patients with essential hypertension, 38 hypertensive patients and 37 normotensive healthy subjects were compared. In patients, the maximal 5-HT uptake velocity was reduced. The density of binding sites for 3H-imipramine was elevated in hypertensive females, but unchanged in males. The sensitivity of 5-HT uptake to trazodone was unchanged in patients. Half-maximal concentrations of 5-HT for inducing a shape change reaction of platelets were positively correlated with diastolic blood pressure in male patients and were reduced in female mild hypertensives. It is suggested that these changes are likely to be involved in the pathogenesis of hypertension.
 ...
PMID:[Function of the serotoninergic system of blood platelets in patients with hypertension]. 129 66

In spite of the relatively large amount of in vitro and in vivo data indicating that, in a number of ways, cerebral arteries are pharmacologically different from peripheral arteries, the mechanisms responsible for these differences are far from clear. An understanding of these mechanisms is particularly important for a rational approach to the treatment of disorders of the cerebral circulation including migraine, hypertension and the responses of cerebral vessels to subarachnoid haemorrhage. This review outlines electrophysiological data which are available from cerebrovascular smooth muscle cells, including the possibility that inwardly-rectifying potassium channels, active at potentials close to the resting membrane potential, are intimately involved in the changes in smooth muscle tone which couple blood flow to regional changes in nerve cell activity. The membrane potential changes in response to perivascular nerve stimulation, noradrenaline, 5-hydroxytryptamine and endothelium-derived hyperpolarizing factor are also described, together with the underlying membrane mechanisms and their relationship to smooth muscle contraction and relaxation.
 ...
PMID:Electrophysiology of cerebral blood vessels. 130 95

Nifedipine-resistant Ca(++)-induced contractions (NR-Ca(++)-contraction) were compared in the tail arteries from SHRs and WKYs (5 and 13 week old). NR-Ca(++)-contraction of tail artery was defined as follows: Ca(++)-induced contraction in the presence of norepinephrine (NE) (10(-5) M) or 5-hydroxytryptamine (5-HT) (10(-5) M) in Ca(++)-free medium containing EGTA (0.1 mM) and nifedipine (10(-6) M). NR-Ca(++)-contractions in arteries from 5 week old SHRs and WKYs were not different. In contrast, NR-Ca(++)-contractions in arteries from 13 week old SHRs were about 2-fold greater than in arteries from 13 week old WKYs. In arteries from 13 week old WKYs and SHRs, nitroglycerin (10(-5) M) significantly reduced the NR-Ca(++)-contraction in the presence of 5-HT but not in the presence of NE. The reduction was inhibited by the presence of methylene blue (3 x 10(-6) M). 8-Bromo-cGMP (10(-4) M) reduced significantly the NR-Ca(++)-contraction in the presence of 5-HT in arteries from 13 week old SHRs and WKYs. The present experiments clearly demonstrated that the NR-Ca(++)-contractions (both in the presence of NE and 5-HT) in 13 week old SHRs were significantly greater than those in arteries from 13 week old WKYs. These results suggest that in addition to an increase in voltage-operated Ca++ mobilization reported by others, an increase in NR-Ca++ mobilization may contribute to the development of hypertension in SHR.
 ...
PMID:Nifedipine-resistant Ca(++)-induced contraction in tail artery of spontaneously hypertensive rats. 132 37

The possible role of 5-hydroxytryptamine (5HT) and 5HT-receptors in hypertension, already suggested by Page in 1954, has been subject to a renaissance of interest owing to the development of antihypertensive drugs which interact with 5HT-receptors. These drugs, like ketanserin, urapidil and flesinoxan are used as tools to study the role of 5HT and its receptors in hypertension. Some arguments would plead in favour of a certain role of 5HT and 5HT-receptors in the pathogenesis and maintenance of hypertension: hyperresponsiveness of blood vessels from hypertensive patients and animals to 5HT-induced constriction; the antihypertensive/vasodilator activity of the 5HT2-receptor antagonist ketanserin; enhanced sensitivity of platelets from hypertensives to 5HT. However, there are also several arguments which do not support a causal role of 5HT in hypertensive disease: 5HT is not a generally accepted pressor agent, whereas its concentration in the circulating blood is subthreshold; the 5HT2-receptor antagonist ketanserin is the only agent of this type which lowers blood pressure, other 5HT2-receptor blockers (ritanserin; LY 53587) being inactive. The various data and arguments available do not unequivocally support a relevant role of peripheral 5HT and its receptors in hypertensive disease. 5HT2-receptor blockade may, however, have a favourable effect on the microcirculation under pathological conditions. The stimulation of central 5HT1A-receptors by drugs like urapidil, 8-OH-DPAT or flesinoxan, has been demonstrated to induce peripheral sympathoinhibition and a fall in blood pressure. This mechanism appears to be a novel target for centrally acting antihypertensives, clearly different from that of clonidine and related drugs, which are centrally acting alpha 2-adrenoceptor agonists.
 ...
PMID:Serotonergic receptors and drugs in hypertension. 135 65


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