The Journal of pharmacy and pharmacology
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J. Pharm. Pharmacol. · Feb 1990
Resistance of myenteric neurons in the rat's colon to depletion by 1,8-dihydroxyanthraquinone.
Earlier reports have suggested that anthraquinone purgatives in excessive amounts cause degeneration of neurons in the enteric nervous system. Danthron (1,8-dihydroxyanthraquinone) was administered to rats in their drinking water for four months. ⋯ No differences were found between the treated animals and their controls, indicating that the drug does not kill myenteric neurons. These results agree with recent observations on the effects of senna in rats and mice, and do not support earlier claims that myenteric neurons are killed by anthraquinone purgatives.
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J. Pharm. Pharmacol. · Dec 1989
An in-vitro study of the interactions between intravenous induction agents and the calcium antagonists verapamil and nifedipine.
Thiopentone, propofol and etomidate inhibit the contractions of the rat isolated atria and portal vein. The actions of thiopentone and propofol summate with those of verapamil and nifedipine. ⋯ The depressant actions of thiopentone and propofol on the portal vein are associated with a reduced response to calcium. Etomidate does not reduce the response to calcium in this preparation.
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J. Pharm. Pharmacol. · Nov 1989
Vascular effects of propofol: smooth muscle relaxation in isolated veins and arteries.
Isolated hepatic portal veins and aorta taken from the rat were used to investigate the direct action of the intravenous anaesthetic propofol. This compound is known to produce a fall in blood pressure in man and animals and it has been suggested that the hypotension may result from a direct vasodilator action on the veins and arterioles. ⋯ However, the concentrations required to produce this effect in the experiments on veins were significantly lower than those required to produce similar changes in the isolated artery preparation. We conclude that this direct action may contribute towards the hypotensive effects of propofol.
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J. Pharm. Pharmacol. · Jan 1988
Myoclonic seizures in the mouse induced by alphaxalone and related steroid anaesthetics.
The anaesthetic steroids alphaxalone. 5 beta-alphaxalone and pregnanolone each caused myoclonic jerks in mice in a dose-related manner between 4 and 16 mg kg-1 i.v. There was no loss of righting reflex at these doses. The veterinary product Saffan, which contains alphaxalone and alphadalone, also caused myoclonic jerks at 2 mg kg-1 i.v., and a loss of righting reflex at doses of 4 mg kg-1 and above. These effects appear to be unrelated to the wide spectrum of potencies at the GABAA receptor complex of the three individual steroids as potentiators of muscimol, or as attenuators of picrotoxin.
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Plastic ampoules of Water for Injections, JP, and Injection Sodium Chloride, JP, were investigated to determine their particle load. Four batches were studied. The ampoules were twist-opened as they would be in the clinical setting and the total particle load, both inherent and that created in opening, was determined by reading the contents with a HIAC 420 particle counter with a CMB 60 sensor. ⋯ P. standard of the USP XXI. The number of particles found in these opened plastic ampoules was significantly lower than that found in clinically snap-opened glass ampoules and also slightly lower than that found in laboratory heat-opened glass ampoules. Whilst the plastic ampoule has a restricted application because it is not suitable for all drugs, it is concluded that when they are used as the immediate container for Water for Injections and Injection Sodium Chloride they are highly effective in reducing the particulate contamination generated in opening.