The lack of a pronounced preference of prenalterol for the beta-l-adrenoceptor subtype

Rohm, N; Wagner, J.; Schümann, H. J.

doi:10.1007/bf00504235

Cited by 18 publications

(6 citation statements)

References 6 publications

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“…In fact, prenalterol inhibited the effect of terbutaline competitively. Rohm et al (1980) found that prenalterol inhibited the relaxing effect of noradrenaline on the guinea-pig trachea. This is com~atible with the view that prenalterol is a non-selective /?-adrenoceptor ligand with absolute PI-selective, partial, agonistic activity (Hedberg et al 1980).…”

Section: Discussionmentioning

confidence: 96%

“…Thus thechoice of steroid in experiments with tracheal smooth muscle may be critical for the estimation of potency and efficacy of bronchodilators. This is illustrated by the failure to detect the relaxing effect of prenalterol on the carbachol contracted ( I pmol litre-') trachea when corticosterone is substituted for 178-oestradiol (compare Rohm et al 1980with Kenakin & Beek 1980.…”

Section: Discussionmentioning

confidence: 99%

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β1-Adrenoceptors mediating relaxation of the guinea-pig trachea: experiments with prenalterol, a β1-selective adrenoceptor agonist

Johansson

Waldeck

1981

Journal of Pharmacy and Pharmacology

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In the presence of 17 β‐oestradiol, prenalterol, a β1‐selective adrenoceptor agonist, caused a dose‐dependent relaxation of the isolated, pilocarpine‐contracted guinea‐pig trachea. This effect was blocked by the antagonists propranolol (non‐selective) and practolol (β1‐selective) but not by IPS 339 [(t‐butylamino‐3‐ol‐2‐propyl)oximino‐9‐fluorene HCl] (β2‐selective). The relaxing effect of terbutaline, a β2‐selective adrenoceptor agonist, was more efficiently blocked by IPS 339 than by practolol. These data support the hypothesis that the guinea‐pig trachea contains both β1‐ and β2‐adrenoceptors mediating relaxation and that the β1‐adrenoceptors are selectively stimulated by prenalterol. The efficacy of prenalterol was less than that of terbutaline, thus confirming its partial agonistic activity. In the absence of 17 β‐oestradiol, the ability of prenalterol to relax the pilocarpine‐contracted trachea was lost. It is suggested that 17 β‐oestradiol may act as a functional antagonist to pilocarpine as it caused a partial relaxation itself.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

β1-Adrenoceptors mediating relaxation of the guinea-pig trachea: experiments with prenalterol, a β1-selective adrenoceptor agonist

Johansson

Waldeck

1981

Journal of Pharmacy and Pharmacology

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“…Thus, the efficacy of prenalterol in rat heart is intermediary to the efficacy in cat papillary muscle (Hedberg & Mattsson 1981) and guinea pig left atrium (Rohm et al 1980).…”

Section: Discussionmentioning

confidence: 94%

Characterization of Mechanical Effects and β‐Adrenoceptor Binding of Prenalterol in Rat Myocardium

Aass

Hedberg

Skomedal

et al. 1983

Acta Pharmacologica et Toxicologica

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The partial P-agonist prenalterol has been found to differ from the full agonist isoprenaline in some aspects of its cardiac action. We therefore studied in rat myocardium whether prenalterol elicited the same qualitative changes of the contraction-relaxation cycle as was previously found for isoprenaline. We also measured binding of prenalterol to P-adrenoceptors. Prenalterol augmented relaxation more than contraction and thus evoked the same qualitative changes of the contraction-relaxation cycle as did isoprenaline. However, the response developed slowlier than that to isoprenaline, and the effect on relaxation followed a more protracted time course than the effect on contraction. Prenalterol bound non-selectively to PIand P2adrenoceptors in both heart and lung broken cell preparations. pKd for binding to P-adrenoceptors and pDz values for functional effects in heart were similar, i.e. prenalterol had to occupy half the amount of Padrenoceptors in order to evoke half-maximal functional effects. The non-selective a-blocker phentolamine potentiated the effects of prenalterol on contraction, but did not change the equilibrium binding of prenalterol to cardiac P-adrenoceptors. Phentolamine did not change the potency and efficacy of isoprenaline. Thus, although prenalterol qualitatively evoked the same response as isoprenaline, it also exhibited some properties which differed.

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“…In effect, binding experiments have shown that prenalterol binds non-selectively to both 0, -and P2-adrenoreceptors (Johansson & Waldeck, 1980; Hedberg, Mattson & Carlsson, 1980) and while no differences in tissue affinity could be demonstrated, different stimulus-response relationships of different tissues were observed (Kenakin & Black, 1980) so that categorization of this drug is perhaps not so clear-cut (Rohim, Wagner & Schumann, 1980). The inotropic effect is reported to be evident without a significant increase in heart rate (Carlsson, Dahlof & Hedberg, 1977).…”

Section: Introductionmentioning

confidence: 95%

“…Prenalterol [S-( -)-I -4 hydroxyphenossy)-3-isopropylaminopropanol-2-hydrochloride] is a new drug from Hassle-Astra Pharmaceutical, AB, which activates P,-receptors in the heart in doses which have no significant effect on &receptors in the .lungs and blood vessels (Ariniego et at., 1979; Hutton et ul., 1980;Johnsson et al, 1978; Knaus et at., 1978, Ronn el at., 1980). In effect, binding experiments have shown that prenalterol binds non-selectively to both 0,and P2-adrenoreceptors (Johansson & Waldeck, 1980; Hedberg, Mattson & Carlsson, 1980) and while no differences in tissue affinity could be demonstrated, different stimulus-response relationships of different tissues were observed (Kenakin & Black, 1980) so that categorization of this drug is perhaps not so clear-cut (Rohim, Wagner & Schumann, 1980). The inotropic effect is reported to be evident without a significant increase in heart rate (Carlsson, Dahlof & Hedberg, 1977).…”

Section: Introductionmentioning

confidence: 99%

Haemodynamic Effects of Prenalterol in Acute Myocardial Ischaemia in Open Chest Pigs

Branzi

Binetti

Specchia

et al. 1983

Clin Exp Pharma Physio

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The haemodynamic effects of prenalterol, a new sympathomimetic agent, have been studied in anaesthetized open-chest pigs with acute myocardial ischaemia provoked by left anterior descending coronary artery ligation. A group of eight animals was infused with saline and served as control (C). In both groups the ligation of the left anterior descending coronary artery determined a significant (P less than 0.05) reduction of aortic flow, maximum left ventricular (LV) dp/dt with no changes in heart rate. The infusion of a first dose of 30 micrograms/kg of prenalterol restored the depressed haemodynamics but increased significantly the heart rate in the prenalterol group while the saline infused group did not show any significant changes. The haemodynamic effects of prenalterol were still evident 25 min after the infusion. The subsequent administration of a second dose of 60 micrograms/kg of prenalterol resulted in a further improvement of the aortic flow, LV dp/dt and heart rate which reached values higher than in the basal condition. The positive inotropic effect was not associated with changes in stroke volume, therefore the increase in aortic flow was essentially due to an increase of the heart rate. It is concluded that prenalterol is a powerful inotropic agent in acutely infarcted animals. Its action on aortic flow appears to be related to an increase in heart rate in contrast to some previous observations.

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The lack of a pronounced preference of prenalterol for the beta-l-adrenoceptor subtype

Cited by 18 publications

References 6 publications

β1-Adrenoceptors mediating relaxation of the guinea-pig trachea: experiments with prenalterol, a β1-selective adrenoceptor agonist

β1-Adrenoceptors mediating relaxation of the guinea-pig trachea: experiments with prenalterol, a β1-selective adrenoceptor agonist

Characterization of Mechanical Effects and β‐Adrenoceptor Binding of Prenalterol in Rat Myocardium

Haemodynamic Effects of Prenalterol in Acute Myocardial Ischaemia in Open Chest Pigs

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