Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Octopamine”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

1,494 records · Page 83Linked to original sources
PubMed1983

The sympathomimetic activity of N-isopropyloctopamine in vitro.

Isolated right and left guinea-pig atria, guinea-pig tracheae and rabbit aortic strips were used to define the sympathomimetic properties of N-isopropyloctopamine. This compound was a highly beta selective, direct-acting adrenergic agonist, approximately 200- and 440-fold less potent than isoproterenol in cardiac and smooth muscle, respectively. It was nearly a full agonist in both cardiac and smooth muscle without appreciable selectivity for either beta-1 or beta-2 receptors and had no demonstrable beta blocking activity. No alpha adrenergic activity was detectable within the concentration range tested. The chronotropic effect of N-isopropyloctopamine was very persistent and resistant to repeated washing of the tissues, which may reflect unusually firm binding to beta receptors.

Animals↗
PubMed1983

[The effect of norfenefrine on circulation, plasma catecholamines and metabolism at rest and during exertion].

In a single-blind random cross-over study the influence of a Norfenefrin infusion (2-4 mg/kg per minute) on circulation, carbohydrate and fat metabolism, catecholamines, growth hormone, cortisol, and insulin was investigated. The investigations were carried out on 12 healthy male physical education students at rest and during physical exercise. Under Norfenefrin, heart rate was reduced at rest (-30%) and under low and medium work load (150 watts: -9%); under maximal work load heart rate remained unchanged. Systolic blood pressure at rest increased by 29%; the results under physical exercise differ only slightly, and during increased work load they did not differ significantly. Diastolic blood pressure, in contrast, increased at rest (+23%) and under submaximal (150 watts: +12%) and maximal work load (+12.5%). The product of systolic blood pressure and heart rate was significantly decreased at rest under Norfenefrin, whereas it tended to decrease only slightly during work load. Adrenaline remained unchanged, while noradrenaline had a tendency to decrease only slightly during submaximal work load and was significantly lower during maximal work load. Glucose, lactate, glycerol, free fatty acids, and triglycerides, as well as growth hormone, cortisol, and insulin, remained unchanged. The physical working capacity remained unaffected. These observations confirm the predominant alpha-receptor-stimulating effect of Norfenefrin. The decrease in noradrenaline during exercise indicates the ability of Norfenefrin to interfere with the autoregulation of transmitter release and to replace endogenous noradrenaline.

2-Hydroxyphenethylamine↗
PubMed1983

[Clonidine for the treatment of heroin withdrawal syndrome].

In an open study of 50 patients with heroin addiction, clonidine was efficacious by mouth in the treatment of acute heroin-withdrawal syndrome. Mean administration of clonidine (on an "as-needed" basis) was 5 days (maximum 7 days), whilst the mean daily dosage ranged from 0.112 mg to 0.468 mg, the maximum requirement occurring on day 2 of withdrawal and sinking thereafter. Since insomnia was not influenced by clonidine, we offered 100 mg doxepine and/or 10 mg nitrazepam (the latter only until day 4 of treatment). Under this medication a sudden, dramatic decrease in blood pressure was not seen, mean blood pressure and pulse rate were not markedly altered; this may, perhaps, be a consequence of the blocking effect of doxepine on the peripheral hypotensive actions of clonidine. Of the 9 drop-outs from treatment, five (10% of the total 50) were certainly directly attributable to the lack of response to clonidine, representing a failure of therapy in 10% cases at least.

2-Hydroxyphenethylamine↗
PubMed1981

[Release of norfenefrine from sustained-release formulations by an in vitro dissolution model. Simulation of "drug levels" by calculation using pharmacokinetical constants and comparison with in vivo course of action (author's transl)].

Drug release and dissolution behaviour of 1-(3'-hydroxyphenyl)-2-amino-ethan-1-ol hydrochloride (norfenefrine-HCl) from a sustained-release norfenefrine preparation (Esbuphon) were tested by an in vitro dissolution model in comparison with other norfenefrine formulations. By using pharmacokinetical constants, relative "drug levels" were calculated and compared with the activity curves from animal experiments. Conformities in time course were shown. Variations are discussed. The application of the model is justified if determination of serum concentration of norfenefrine cannot be done.

2-Hydroxyphenethylamine↗
PubMed1981

Haemodynamic effects of amezinium in man.

After single i.v. (5 and 10 mg) and p.o. (10, 20 and 40 mg) administrations, 4-amino-6-methyoxy-1-phenyl-pyridazinium methyl sulfate (ameziniummetilsulfate, LU 1631, Regulton), in the following briefly called amezinium, a new antihypotensive agent, was studied by non-invasive methods for its cardiovascular action in comparison with norfenefrine (10 mg i.m. and 40 mg p.o.) and dihydroergotamine (1 mg i.m. and 4 mg p.o.) in a group of 33 volunteers. The action pattern of 10 mg amezinium i.v. consisted of a significant rise in arterial blood pressure (systolic 23%, diastolic 14%) with an increase in pulse pressure (38%) and a reflex fall in heart rate (9%). The total peripheral resistance was increased by 29%, with a moderate reduction of cardiac output (5%; n.s.) and an increase of the stroke volume (6%; n.s.). A clear positive inotropic effect was discernible by the significant reduction of heart rate, corrected preejection period (delta PEP; 13 ms), left ventricular ejection time (delta LVET; 8 ms; n.s.) and a decrease of the ratio PEP/LVET (-0.028). This pattern of action points to stimulation of vascular alpha- as well as cardiac beta 1-adrenoceptors and is in accordance with the findings from animal experiments as amezinium acts via endogenous noradrenaline. The reference substance norfenefrine exhibited purely alpha-sympathomimetic action, whereas dihydroergotamine presumably exerted venoconstrictive and central sympatholytic effects. The effects of amezinium after p.o. administration on the circulation were similar to those after i.v. administration, whereas the reference substances did not reveal any definite pharmacodynamic action when given p.o. Single administrations of the various p.o. doses of amezinium gave rise to a dose-dependent increase of the systolic blood pressure, persisting over the 180 min of the investigation period. From the dose-response relationships after parenteral and oral administration a relative enteral efficacy of 50-80% was established, which corresponds well with bioavailability data. The results show amezinium to have potent, long-lasting blood pressure increasing and positive inotropic actions in man after oral as well as parenteral administration.

2-Hydroxyphenethylamine↗
PubMed1981

Cardiovascular effects of amezinium in humans during passive upright tilt in comparison with norfenefrine and dihydroergotamine.

20 min after single i.v. administration of 10 mg 4-amino-6-methoxy-1-phenyl-pyridazinium methyl sulfate (ameziniummetilsulfate, LU 1631, Regulton), in the following briefly called amezinium, a new antihypotensive agent, was studied in comparison with 10 mg norfenefrine i.m. and 1 mg dihydroergotamine i.m. during orthostatic stress on a tilt table in a total group of 29 healthy volunteers with stable cardiovascular conditions. The study of each substance was preceded by a control tilting test. After amezinium a higher systolic blood pressure of 10 to 15 mmHg in comparison with the control test was maintained during 5 min upright tilt with both a smaller increase in the rise of heart rate and decrease in stroke volume. In comparison with control, pulse pressure was also clearly increased whereas cardiac output and total peripheral resistance were not significantly different. The increase in stroke volume in comparison with control was a result of the positive inotropic effect on the one hand, which could be seen in both a diminished prolongation of the preejection period and increase in the PEP/LVET ratio, and an increased venous return to the heart on the other hand. Systolic blood pressure and heart rate after norfenefrine were principally similar to those after amezinium, whereas the effect on stroke volume was of minor magnitude because of the absence of a positive inotropic action. Moreover, cardiac output decreased more with higher total peripheral resistance in comparison to control. Besides a slight reduction in heart rate, dihydroergotamine did not reveal any significant differences from control during orthostatic stress. At the dose studied, amezinium seemed to produce a better adaptation to passive upright tilt than the reference substances.

2-Hydroxyphenethylamine↗
PubMed1976

[Pharmacokinetics of DL-norephedrine 14C in the rat].

After i.v. administration of DL-norephedrine 14C to the rat (535 mug/kg), approximately 75% of the radioactivity was eliminated during the first 18 hr in the urine. Beside the unchanged drug (71.5% of the total urinary radioactivity), the main metabolite was alpha-methyloctopamine (18%), a parahydroxylated derivative of which 68% were excreted as glucuronide conjugates. Kinetic studies of DL-norephedrine in different organs showed that the affinity of tissues for the amine did not change with time. Captation was important and rapid in lungs, adrenals, spleen and heart. The brain was marked by a slow increase of drug level during the first 2 hr. However, the terminal semi-exponential kinetic slopes of DL-norephedrine concentration showed that the elimination processes of the drug were the same in each tissue. The affinity of tissues for alpha-methyloctopamine was shown to be much more specific; its uptake was higher in organs which are rich in adrenergic nerve endings (heart, adrenals and spleen). These results confirm the role of this hydroxylated amine as a false neurotransmitter. A whole body autoradiography in the mouse showed an important uptake of DL-norephedrine 14C in salivary glands and periocular structures.

Animals↗
PubMed1976

[Double-blind study on the therapy of postural hypotension in psychotic patients under psychotropic medication (author's transl)].

13 psychotic patients developing various degrees of postural hypotension during neuroleptic or antidepressant treatment were additionally given either placebo or a mineralocorticoid or a sympathomimetic drug. As shown by Schellong tests during therapy the best effect on postural hypotension was achieved by the mineralocorticoid. The statistical evaluation of the randomised study was significant.

Adult↗
PubMed1976

The effect of normalization of plasma amino acids on hepatic encephalopathy in man.

Previous work from this laboratory has suggested that the plasma amino acid pattern, known to be deranged in hepatic encephalopathy, may be related causally. In order to test this hypothesis, 23% dextrose and a special amino acid solution whose components were calculated to normalize the plasma amino acid pattern were infused in 11 patients, eight with chronic cirrhosis and acute exacerbation (Group 1) and three patients with fulminant hepatitis (Group 2), in amounts of up to 120 Gm. of protein equivalent per 24 hours. Plasma amino acids were abnormal but different in both groups. In Group 1 (cirrhosis) changes in plasma amino acid pattern including elevated phenylalanine, tyrosine, glutamate, aspartate, and methionine and decreased valine, leucine, and isoleucine. In Group 2 all amino acids were elevated, with the exception of the branched chains which were normal. Hepatic encephalopathy improved in all patients in Group 1 and in one of three patients in Group 2 following the infusion. The ratio (see article) showed an excellent correlation with a grade of encephalopathy. When this ratio, previously 1.0 in the presence of encephalopathy, returned to the normal value near 3.0 to 3.5, encephalopathy improved. An excellent correlation was obtained between the ratio and the grade of encephalopathy and was dose related as well. The results suggest that different amino acid patterns in hepatic encephalopathy of differing etiologies require treatment modalities which may differ for the two types of encephalopathy. Whereas amino acid infusion appears to be a valuable, efficacious way of providing nutrition in treating hepatic encephalopathy in patients with cirrhosis and acute deterioration and coma, other means of therapy such as plasms "laundering" appear to be necessary in patients with fulminant hepatitis.

Adult↗