Actions of quazodine (MJ1988) on smooth muscle

Parratt, J. R.; Winslow, E.

doi:10.1111/j.1476-5381.1971.tb07191.x

Cited by 9 publications

(5 citation statements)

References 13 publications

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“…Oxyfedrine (01-5 [g/ml; 19 preparations) depressed the amplitude of pendular movement in the rabbit duodenum. The effect was similar to that of isoprenaline (Bowman & Hall, 1970), and of the phosphodiesterase inhibitor quazodine (Parratt & Winslow, 1971), in that inhibition was slow in onset and that no overshoot in contraction height was observed on washing. This is in contrast to the effects of a-adrenoceptor stimulation (Bowman & Hall, 1970).…”

Section: Resultssupporting

confidence: 58%

“…This stimulation of portal venous smooth muscle is unlikely to be due to potentiation of endogenously released noradrenaline since oxyfedrine, unlike cocaine, failed to potentiate the effects of noradrenaline. In high concentrations, isoprenaline also increases spontaneous activity in the portal vein (Johansson, Jonsson, Axelsson & Wahlstrom, 1967;Parratt & Winslow, 1971). This is an effect at a1-adrenoceptor sites and is prevented by phenoxybenzamine (Johansson et al, 1967).…”

Section: Discussionmentioning

confidence: 97%

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Effects of oxyfedrine on isolated portal vein and other smooth muscles

Mackenzie¹,

Parratt²

1973

British J Pharmacology

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Summary1. Oxyfedrine (0O01-1P0 ,g/ml), inhibited spontaneous myogenic activity in rat isolated portal vein and carbachol-induced contractions of rat isolated uterus, and relaxed the rabbit duodenum and the guinea-pig tracheal chain preparation. These actions were prevented by the f8-adrenoceptor blocking drug alprenolol. Oxyfedrine was a relatively weak ,3-adrenoceptor stimulant (10-100 times less active than isoprenaline) but its actions were more prolonged. 2. In the same concentrations, oxyfedrine reduced or prevented the inhibition of myogenic activity of the rat portal vein induced by isoprenaline and by repeated doses of oxyfedrine itself, acting as a partial agonist at f3-adrenoceptor sites. 3. Oxyfedrine, 1-12 ,ug/ml increased myogenic activity in the rat portal vein. This effect was not due to direct or indirect stimulation of a-adrenoceptors (because it was unaffected by phentolamine) or to potentiation of acetylcholine or 5-hydroxytryptamine. 4. Oxyfedrine (>20 ,g/ml) inhibited spontaneous myogenic activity in the portal vein and relaxed the saphenous vein contracted with noradrenaline. This spasmolytic effect of the drug was not due to 8-adrenoceptor stimulation or to inhibition of phosphodiesterase since it was unaffected by alprenolol and by concentrations of imidazole which antagonized the effects of the active phosphodiesterase inhibitor, papaverine. In the portal vein this effect of oxyfedrine was similar to that of the calcium inhibitor iproveratril; some of the effects of oxyfedrine on venous smooth muscle may be mediated through effects on calcium transport.

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Section: Resultssupporting

confidence: 58%

Section: Discussionmentioning

confidence: 97%

Effects of oxyfedrine on isolated portal vein and other smooth muscles

Mackenzie¹,

Parratt²

1973

British J Pharmacology

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“…In an effort to further demonstrate the utility of this suite of transformations, we explored the monofluorination, difluorination and trifluoromethylthiolation of quazodine ( 58 ), 25 a cardiac stimulant. As depicted in Scheme 1 , each of these transformations proceeded smoothly and provided access to the unique quazodine derivatives 59–61 in good to excellent yield.…”

Section: Resultsmentioning

confidence: 99%

Direct heterobenzylic fluorination, difluorination and trifluoromethylthiolation with dibenzenesulfonamide derivatives

et al. 2018

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“…Quazodine is such a drug; its cardiac stimulant effects are unaltered by B-adrenoreceptor blocking agents (Parratt & Winslow, 1971a). Quazodine increases the iintracellular concentration of cyclic AMP by inhibiting phosphodiesterase (Amer & Browder, 1971 ;Parratt & Winslow, 1971b): in the myocardium, this would be expected to increase contractility. An increase in myocardial contractility was clearly demonstrated when quazodine was infused prior to endotoxin administration.…”

Section: Discussionmentioning

confidence: 99%

The Haemodynamic Effects of Quazodine, a Cardiac Stimulant, in Experimental E. Coli Endotoxin Shock in the Cat

Parratt

Winslow

1974

Clin Exp Pharmacol Physiol

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S U M M A R Y1. Intravenous injections of quazodine (6,7-dimethoxy-4-ethylquinazoline, 0.5 mg/kg per min) in pentobarbitone-anaesthetized cats increased heart rate, the maximum rate of pressure development in the left ventricle (LV dP/dt max.), cardiac output and myocardial blood flow, and decreased systemic arterial blood pressure. The effects of this cardiac stimulant were examined 1,2, and 3 h after the intravenous administration of 2 mg/kg of E. coli endotoxin.2. During the endotoxin shock phase (> 1 h after endotoxin) the most pronounced effects were decreases in systemic blood pressure and cardiac output and a severe metabolic acidosis.3. Quazodine failed to increase cardiac output during endotoxin shock and the effects on the heart rate and LV dp/dt max. were much reduced. In contrast, quazodine-induced vasodilatation was much more marked.4. It is concluded that there is profound myocardial depression in severe endotoxin shock in the cat and that this cannot be significantly modified by quazodine.

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Actions of quazodine (MJ1988) on smooth muscle

Cited by 9 publications

References 13 publications

Effects of oxyfedrine on isolated portal vein and other smooth muscles

Effects of oxyfedrine on isolated portal vein and other smooth muscles

Direct heterobenzylic fluorination, difluorination and trifluoromethylthiolation with dibenzenesulfonamide derivatives

The Haemodynamic Effects of Quazodine, a Cardiac Stimulant, in Experimental E. Coli Endotoxin Shock in the Cat

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