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Biomedical subjects

B J Pleuvry

Publications and source records attributed to B J Pleuvry.

At least 37 records · Page 2Linked to original sources
PubMed1987

The respiratory effects of oral ethyl loflazepate in volunteers.

A volunteer study was undertaken to assess the respiratory effects of ethyl loflazepate, a new benzodiazepine, and to correlate these with plasma concentrations of the active metabolites. Twelve volunteers were given placebo, 2 mg ethyl loflazepate, and 6 mg ethyl loflazepate on separate occasions. Respiration and plasma metabolite levels were assessed hourly for 8 h and at 24 h. The 6 mg ethyl loflazepate treatment produced a significant decrease (P less than 0.02) in the ventilatory response to carbon dioxide at 5 h. However this did not equate with a peak in plasma metabolite concentrations which were maintained at a plateau level from 4 to 24 h.

Adult↗
PubMed1987

Stimulant action of pethidine on the pregnant rat uterus in-vitro.

Pethidine's stimulant action on the 22-day pregnant rat isolated uterus does not involve receptors sensitive to methysergide and is unlikely to involve the synthesis and release of endogenous prostaglandins. The sensitivity of pethidine-induced contractions to verapamil suggests that mobilization of extracellular calcium is necessary for pethidine's action.

Animals↗
PubMed1987

The effect of meptazinol on the guinea-pig sphincter of Oddi in-vitro.

Meptazinol causes a dose-dependent contraction of the guinea-pig sphincter of Oddi in-vitro. This was antagonized by atropine in concentrations which blocked the contractile response to acetylcholine but not that to KCl. Naloxone was unable to block the response of the tissue to meptazinol, and other opioid drugs had inconsistent effects. Although meptazinol has significant anticholinesterase activity on this preparation, comparison with neostigmine suggests that this is irrelevant to its contractile action.

Acetylcholine↗
PubMed1986

Differing potencies of muscle relaxants on rat and guinea-pig phrenic nerve diaphragm preparations.

The sensitivities of two in-vitro preparations to neuromuscular blocking agents have been compared. The guinea-pig phrenic nerve diaphragm preparation proved to be more sensitive to vecuronium, atracurium and pancuronium than the equivalent preparation from the rat. Only tubocurarine had a similar potency on the preparations from both species. This would suggest that the guinea-pig diaphragm would be the most appropriate bioassay preparation if only small quantities of drug were available. Small differences in the cholinesterase content of the preparations was not thought to be a likely reason for the differences between the two preparations.

Animals↗
PubMed1985

Effect of meptazinol on neuromuscular transmission in the isolated rat phrenic nerve-diaphragm preparation.

Meptazinol has been shown to have significant effects on neuromuscular transmission in the isolated rat phrenic nerve-diaphragm preparation. The response of the preparation to indirect electrical stimulation was increased in a concentration-dependent manner by meptazinol hydrochloride 2-32 micrograms ml-1. Meptazinol 0.5-2 micrograms ml-1 antagonized the effects the tubocurarine on this preparation, and in concentrations of 1 microgram ml-1 and greater, potentiated suxamethonium. These effects were similar to those obtained with neostigmine and it was demonstrated that meptazinol had significant anti-cholinesterase activity in the concentrations used. Inhibition of cholinesterase with ecothiopate revealed a neuromuscular blocking activity of meptazinol in concentrations as low as 0.25 micrograms ml-1.

Animals↗
PubMed1985

Actions of morphine, pethidine and pentazocine on the oestrus and pregnant rat uterus in vitro.

The effects of morphine, pethidine and pentazocine have been studied on the rat uterus in vitro. Morphine caused a concentration-dependent decrease in the frequency of contraction of the oestrus uterus. In contrast, both pethidine and pentazocine enhanced the contraction rate. The pregnant uterus showed little response to morphine in the concentrations studied, whereas there was an augmented response to the stimulant actions of pethidine and pentazocine. Naloxone 1-100 ng ml-1 was unable to antagonize the uterine responses to the opioids, but higher concentrations of naloxone, when administered alone, slowed the frequency of the myogenic activity.

Analgesics, Opioid↗
PubMed1985

Some actions of sodium nitroprusside and glyceryl trinitrate on guinea-pig isolated trachealis muscle.

The smooth muscle relaxant actions of sodium nitroprusside and glyceryl trinitrate have been compared to those of aminophylline and isoprenaline on isolated guinea pig trachealis muscle. Ethacrynic acid (0.25 X 10(-4) M), an alkylator of sulphydryl groups, interacted differently with the four agents. In the presence of ethacrynic acid the concentration response curve of the muscle preparation to sodium nitroprusside and glyceryl trinitrate was shifted to the higher concentration ranges and the maximum response was severely reduced. The concentration response curve for isoprenaline was shifted to the higher concentration ranges with no change in the maximum response and the response to aminophylline was unchanged. These results argue against common intermediate sites of action involving sulphydryl groups of the four agents in guinea-pig trachealis.

Aminophylline↗
PubMed1984

Respiratory and sedative effects of triazolam in volunteers.

Two oral doses of triazolam, 0.5 mg and 0.25 mg, have been compared with placebo in respect of their effects on ventilation, ventilatory response to carbon dioxide, heart rate, arterial pressure, sedation and performance in a variety of psychological tests in 12 healthy volunteers. The study was double-blind. Although triazolam caused dose-dependent sedation it did not decrease significantly the ventilatory response to carbon dioxide. Respiratory rate was increased by triazolam. After triazolam 0.5 mg, increases in sedation score and deficits in cognitive function were still apparent 6 h after administration. Triazolam 0.25 mg produced no significant impairment of performance in any test after 3 h. The sensitivity of a number of psychological tests to triazolam has been discussed.

Adult↗
PubMed1984

Diflunisal and blood acid base status in the rabbit.

Both diflunisal and acetylsalicylic acid given orally caused respiratory alkalosis and metabolic acidosis. However the fall in standard bicarbonate was much less in diflunisal-treated rabbits and pH in these animals remained elevated for the duration of the experiment. Whilst the severity of the fall in arterialized venous PCO2 was a good indicator of the degree of acetylsalicylic acid intoxication this was not the case for diflunisal as fatalities occurred with trivial changes in PCO2. Diflunisal toxicity was associated with markedly elevated temperatures. This was not observed in acetylsalicylic acid-treated rabbits.

Acid-Base Equilibrium↗
PubMed1983

Interactions of morphine and methotrimeprazine in mouse and man with respect to analgesia, respiration and sedation.

Interactions between morphine and methotrimeprazine have been studied in mice and man with respect to analgesia or antinociceptive activity, respiratory effects and sedation. The volunteer study was a double-blind cross-over trial with 10 volunteers. In mice, methotrimeprazine only possessed antinociceptive activity in doses which caused marked sedation. However, small non-sedative doses of methotrimeprazine potentiated the analgesic action of morphine. The volunteer study did not confirm this finding in man. Methotrimeprazine 7.5 mg i.m. caused significant sedation, but did not alter the effects of morphine 5 mg on pain threshold or ventilatory response to carbon dioxide.

Adult↗
PubMed1983

The effect on the rat isolated atria of amiodarone in the presence of either ouabain or verapamil.

Amiodarone causes a decrease in the rate of contraction of the rat isolated atria and has a negative inotropic action in the paced preparation. Interactions occur between amiodarone and ouabain and amiodarone and verapamil. It is possible that the clinically reported drug interaction with amiodarone may have a component of direct interactions on the myocardium rather than solely changes in plasma protein binding.

Amiodarone↗
PubMed1982

Alfentanil: a study of its analgesic activity and interactions with morphine in the mouse.

Alfentanil has a short duration action which did not markedly increase with increasing dose in mice. It is approximately one-fourth as potent as fentanyl. Repeat injections gave reproducible analgesic effects but depression of respiratory rate increased when repeat injections were given on the basis of cessation of analgesic activity. Alfentanil appeared to reduce the analgesic effect of morphine given 30-60 min after alfentanil administration. This has been demonstrated with injection of alfentanil 15 min before, simultaneously with and 30 min after morphine injection. There were not significant effects on depression of respiratory rate produce by morphine.

Alfentanil↗