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Biomedical subjects

S HUKOVIC

Publications and source records attributed to S HUKOVIC.

At least 19 recordsLinked to original sources
PubMed1961

Responses of the isolated sympathetic nerveductus deferens preparation of the guinea-pig.

An isolated ductus deferens preparation together with the sympathetic hypogastric nerve of the guinea-pig is described. While the preparation showed no spontaneous contractions, nerve stimulation produced longitudinal contractions. The responses to successive periods of nerve stimulation remained constant for several hours. After noradrenaline had been added to the bath fluid for 30 min and then the fluid repeatedly changed to wash out the noradrenaline, the effect of nerve stimulation was greatly increased but declined in the course of 1 hr to the original height. Cocaine also increased the response to stimulation. Preparations made from guinea-pigs which had previously received reserpine responded to nerve stimulation with progressively diminishing contractions. In these circumstances, the administration of noradrenaline restored the response to nerve stimulation to that seen originally.

Cocaine↗
PubMed1960

Anoxia and ventricular fibrillation; with a summary of evidence on the cause of fibrillation.

Experiments are described showing that ventricular fibrillation is more readily produced in isolated rabbit hearts by electrical stimulation when the oxygen supply to the heart is reduced. This evidence completes investigations which have been made into factors affecting the production of fibrillation. These investigations have shown that factors which shorten the duration of the action potential, particularly those which cause the "plateau" to disappear, facilitate fibrillation, and those which lengthen the duration of the action potential prevent fibrillation. The reason for the length of the cardiac action potential may therefore be to prevent fibrillation. When the action potential is of normal length the fact that two adjacent fibres are out of phase does not matter; the one which is first to contract is not re-excited by the one which is second to contract, because at that moment the first is inexcitable. If the action potential is short, then the first may be already repolarized and may be excited by spread of excitation from the second. Factors which inhibit metabolism shorten the action potential.

Action Potentials↗
PubMed1960

The action of sympathetic blocking agents on isolated and innervated atria and vessels.

A preparation is described of isolated rabbit atria with both vagus and sympathetic nerves. The action on it of bretylium and of choline 2,6-xylyl ether bromide (TM10) was studied. A concentration of breylium sufficient to abolish the response to sympathetic stimulation also depressed the response to vagal stimulation. The effect was reversible, though more easily with choline xylyl ether. Both drugs abolished the accelerating action of acetylcholine in the presence of atropine, but they augmented the action of tyramine, and did not reduce that of amphetamine. In the vessels of the perfused rabbit ear they abolished the constrictor effect of nervous stimulation and of acetylcholine, but increased that of tyramine.

Acetylcholine↗
PubMed1959

Isolated rabbit atria with sympathetic nerve supply.

The atria of the rabbit heart have been isolated together with their sympathetic nerves, so that the latter could be stimulated and the effect on the rate and amplitude of beating could be measured. Cocaine and phenoxybenzamine increased the response to stimulation. When the preparation was from rabbits previously given reserpine, stimulation of the sympathetic nerves caused inhibition. This inhibition was increased by eserine and abolished by atropine.

Animals↗