Plasma catecholamines in hepatic coma and liver cirrhosis: Role of octopamine

Hörtnagl, Heide; Lochs, Herbert; Kleinberger, G; Hackl, J. M.; Hammerle, A. F.; Binder, Heinrich; Wewalka, F

doi:10.1007/bf01746264

Cited by 17 publications

(4 citation statements)

References 25 publications

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“…Activation of the human α 2A ‐adrenoceptor by octopamine is likely to be particularly important under conditions such as hepatic and renal encephalopathy, where the circulating levels of octopamine are substantially increased (Kinniburgh & Boyd, 1979). Normal human plasma octopamine concentrations are found in the range 0.23 to 1 ng ml −1 (1.5 to 6.5 nM (Kinniburgh & Boyd, 1979; Bozzi et al , 1981) but concentrations up to 59.5 ng ml −1 (0.4 μM) have been found in patients with hepatic coma (Hörtnagl et al , 1981). The latter value is close to the threshold concentration for the effectiveness of (‐)‐ m ‐octopamine demonstrated in the present study for the inhibition of cyclic AMP production.…”

Section: Discussionmentioning

confidence: 99%

Selective inhibition of adenylyl cyclase by octopamine via a human cloned α_2A‐adrenoceptor

Airriess

Rudling

Midgley

et al. 1997

British J Pharmacology

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1 In this study we have compared the abilities of the enantiomers of the structural isomers of the phenolamines, octopamine and synephrine, and the catecholamines, noradrenaline and adrenaline, to couple selectively a human cloned a 2A -adrenoceptor, stably expressed in a Chinese hamster ovary (CHO) cell line, to G-protein linked second messenger pathways mediating an increase and a decrease in cyclic AMP production. 2 The catecholamines couple the a 2A -adrenoceptor to both an increase and a decrease in the rate of cyclic AMP production. In the absence of pertussis toxin pretreatment both catecholamines tested showed a dose-dependent decrease with a maximum at 100 nM. After pertussis toxin pretreatment they both produced a dose-dependent increase in cyclic AMP production with a maximum at 10 mM. 3 The phenolamines, octopamine and synephrine were only able to couple the a 2A -adrenoceptor to a dose-dependent decrease in cyclic AMP production at concentrations up to 1 mM, with the synephrine isomers being more potent than the corresponding octopamine isomers. The meta-isomers of both phenolamines were more potent than the corresponding para-isomers and the (7)-enantiomers were more potent than the (+)-enantiomers. Thus, (7)-meta-synephrine [ (7)-phenylephrine] was the most e ective isomer tested with an observable decrease occurring between 100 nM and 1 mM.4 The e ects of octopamine and the catecholamines on the decrease in cyclic AMP production were additive at submaximal concentrations, whilst octopamine reduced the stimulant e ect of submaximal concentrations of noradrenaline on cyclic AMP production after pertussis toxin pretreatment. 5 The time courses of the inhibitory e ects of both meta-octopamine and noradrenaline were parallel and peaked after a 1 min exposure to the agonist. In contrast, the stimulant e ects of noradrenaline after pertussis toxin pretreatment were of a much slower time course with a maximum e ect occurring after a 5 min incubation period. 6 Since octopamine and synephrine occur naturally in, and are co-released with catecholamines from, mammalian tissues, the results of the present study suggest that the human cloned a 2A -adrenoceptor can be coupled selectively by di erent endogenous agonists to G-protein pathways mediating the regulation of adenylyl cyclase activity.

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Section: Discussionmentioning

confidence: 99%

Selective inhibition of adenylyl cyclase by octopamine via a human cloned α_2A‐adrenoceptor

Airriess

Rudling

Midgley

et al. 1997

British J Pharmacology

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“…However, their observation was carried out by an indirect method and confined to hypotensive patients with renal failure. Fur thermore, recent evidence of elevated plasma levels of norepinephrine has been supplied byother authors [6][7][8]. It is conceivable that the main reason for norepinephrine increase is the stimulation of the adrenergic system byreduced peripheral resistance [2] rather than a diminished hepatic clearance, since the lat ter does not appear significantly impaired in cirrhotics [16],…”

Section: Discussionmentioning

confidence: 99%

Impairment of Blood Pressure Control in Patients with Liver Cirrhosis during Tilting: Study on Adrenergic and Renin-Angiotensin Systems

et al. 1982

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Mean arterial pressure, phenylalanine, tyrosine, norepinephrine and plasma renin activity (PRA) were determined in the plasma of 6 healthy controls and 8 patients with liver cirrhosis receiving a controlled sodium intake (40 mEq/day), after 1 h of bed rest and 10 min after being tilted up at 90 °. After resting, patients showed lower arterial pressure (p < 0.025) and higher plasma levels of phenylalanine (p < 0.005), tyrosine (p < 0.05), norepinephrine (n.s.) and PRA (n.s.) than controls. In spite of a prolonged and marked stimulation of the adrenergic system induced by tilting, arterial pressure of cirrhotics, after an initial increase, decreased significantly. A significant PRA increase was observed in both groups but in patients it was greater and lasted longer, up to 30 min, when PRA and arterial pressure were inversely and significantly correlated. The adrenergic system of cirrhosis then appeared unable to maintain adequate levels of arterial pressure, even though hyperstimulated. The renin-angiotensin system played an important compensatory role in this contest.

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“…A similar increase in renal function was also achieved in the two patients with a normal creatinine clearance ( Table 2). In all nine patients free water clearance decreased during ornipressin infusion from -16 (9) ml/h to -40 (13) ml/h (p<001). The fractional elimination of sodium increased from 0-66 (0-12) to 1-1 (0-5)% (p<0-01).…”

Section: Resultsmentioning

confidence: 84%

Beneficial effect of 8-ornithin vasopressin on renal dysfunction in decompensated cirrhosis.

Lenz

Hörtnagl

Druml

et al. 1989

Gut

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SUMMARY In nine patients with decompensated alcoholic cirrhosis of the liver and impaired renal function the effect of 8-ornithin vasopressin (ornipressin) on renal function and haemodynamic parameters was studied. Ornipressin was infused at a dose of 6 IU/h over a period of four hours. During ornipressin infusion an improvement of renal function was achieved as indicated by an increase of creatinine clearance (76 (15)%; p

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Plasma catecholamines in hepatic coma and liver cirrhosis: Role of octopamine

Cited by 17 publications

References 25 publications

Selective inhibition of adenylyl cyclase by octopamine via a human cloned α_2A‐adrenoceptor

Selective inhibition of adenylyl cyclase by octopamine via a human cloned α_2A‐adrenoceptor

Impairment of Blood Pressure Control in Patients with Liver Cirrhosis during Tilting: Study on Adrenergic and Renin-Angiotensin Systems

Beneficial effect of 8-ornithin vasopressin on renal dysfunction in decompensated cirrhosis.

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Plasma catecholamines in hepatic coma and liver cirrhosis: Role of octopamine

Cited by 17 publications

References 25 publications

Selective inhibition of adenylyl cyclase by octopamine via a human cloned α2A‐adrenoceptor

Selective inhibition of adenylyl cyclase by octopamine via a human cloned α2A‐adrenoceptor

Impairment of Blood Pressure Control in Patients with Liver Cirrhosis during Tilting: Study on Adrenergic and Renin-Angiotensin Systems

Beneficial effect of 8-ornithin vasopressin on renal dysfunction in decompensated cirrhosis.

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Selective inhibition of adenylyl cyclase by octopamine via a human cloned α_2A‐adrenoceptor

Selective inhibition of adenylyl cyclase by octopamine via a human cloned α_2A‐adrenoceptor