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Biomedical subjects

B E Waud

Publications and source records attributed to B E Waud.

34 records · Page 2Linked to original sources
PubMed1975

Depolarization block and phase II block at the neuromuscular junction.

The effects of repeated doses of decamethonium or succinylcholine in muscles of the cat, dog, and rabbit have been examined. In particular, the relation of degree of neuromuscular block to intensity of the electrical change at the end-plate region has been found to be more consistent when the peak spatial gradient of depolarization is used as a measure of electrical effect than when the peak depolarization is used; the reason for this difference is discussed. A plot of twitch height against electrical change provides a convenient frame of reference for following the development of phase II block quantiatively. Examples presented show that the extent and kinetics of phase II block can vary considerably among species or among muscles in a given species.

Anesthesia, Intravenous↗
PubMed1975

In vitro measurement of margin of safety of neuromuscular transmission.

The margin of safety of neuromuscular transmission was measured in isolated guinea pig lumbrical muscles. Twitch height of an indirectly stimulated muscle was reduced stepwise by suitable concentrations of tubocurarine for comparison with the associated occlusion of receptors by the drug. Receptor occlusion was estimated from the effect of tubocurarine on carbachol depolarization measured extracellularly by the moving-fluid electrode technique. Roughly 75-80% of the receptor pool had to be blocked before the twitch height began to fall, and 90-95% had to be blocked before the twitch response was completely abolished. These results agree well with those found previously in vivo. Thus, the present results add further support to the earlier measurements. In particular, artifacts that might have been present because of the complex pharmacokinetic situation in vivo have been ruled out.

Animals↗
PubMed1975

A comparison of the potencies of a series of barbiturates at the neuromuscular junction and on the central nervous system.

The ability of a series of barbiturates to depress the depolarizing action of carbachol at the end-plate of guinea-pig lumbrical muscle was studied. The compounds studied were: amorbarbital, aprobarbital, barbital, barbituric acid, butabarbital, butalbital, dimethylbutylethyl barbituric acid, hexobarbital, mephobarbitak, secobarbital, thiamylal, and thiopental. The depressant activity was sensitive to small changes in structure of the compounds strongly suggesting that a specific receptor site was involved in the interaction of the drug with the tissue. The observed relative potencies on the motor end-plate were compared with their anesthetic potencies assayed on tadpoles. The two potencies went hand-in-hand for all the compounds studied, including the convulsant member of the series.

Animals↗