PubMed HealthSearch

Biomedical subjects

G Hanegreefs

Publications and source records attributed to G Hanegreefs.

5 recordsLinked to original sources

Influence of gallamine, pancuronium, d-tubocurarine and succinylcholine on adrenergic neurotransmission.

The influence of gallamine, pancuronium, d-tubocurarine and succinylcholine on adrenergic neurotransmission was studied in the isolated saphenous vein of the dog. Pancuronium increased the response of vascular smooth muscle to adrenergic nerve stimulation and to exogenous norepinephrine; gallamine, d-tubocurarine and succinylcholine had no effect. The relaxation caused by small doses of acetylcholine added during sympathetic nerve stimulation (prejunctional effect), was inhibited by pancuronium and by gallamine. In vein strips, charged with (3H) norepinephrine, acetylcholine inhibits the catecholamine-efflux evoked by sympathetic nerve stimulation. That inhibition was abolished by gallamine. This confirms that gallamine inhibits the prejunctional effect of acetylcholine on adrenergic neurotransmission. When extrapolated to the intact organism, this means that gallamine and pancuronium will augment the release of norepinephrine by acting as muscarinic antagonists also at prejunctional receptor sites in tissues exposed to combined sympathetic and vagal nerve activity. This mechanism would explain in part the cardiovascular effects of these muscle relaxants.

Acetylcholine

Gallamine and pancuronium inhibit pre- and postjunctional muscarine receptors in canine saphenous veins.

The influence of gallamine, pancuronium, suxamethonium and d-tubocurarine on adrenergic neurotransmission was studied in the isolated saphenous vein of the dog. Pancuronium but not the other muscle relaxants increased significantly the response to sympathetic stimulation and to exogenous norepipephrine; these increases were abolished after blockade of neuronal uptake by cocaine. Pancuronium and gallamine inhibited both the relaxation produced by lower doses of acetylcholine added during sympathetic stimulation (prejunctional effect) and the direct contractions evoked by high doses of the amine (postjunctional effect). In strips previously incubated with [3H]norepinephrine, gallamine had no effect on [3H]norepinephrine efflux in basal conditions and during sympathetic stimulation; it increased markedly the efflux evoked by sympathetic stimulation in the presence of acetylcholine confirming that gallamine inhibits the prejunctional effect of the latter on adrenergic transmission. When extrapolated to the intact organism, the present experiments indicate that gallamine and pancuronium augment the release of norepinephrine in vascular tissue under vagal control, which explains in part the cardiovascular effects of these muscle relaxants.

Acetylcholine

Clinical use of etomidate, influence on blood pressure and heart rate. Comparison with thiopentone and methohexital.

This study deals with blood pressure and heart rate measurements during the use of etomidate after premedication; the injection of etomidate is always preceded by 0.10 mg of fentanyl. Etomidate is compared with thiopentone and methohexitone. There appears to be no gross difference between the drugs as far as the blood pressure is concerned: it is decreased by 15-20%. The influence on the heart rate is typical for each drug: whereas thiopentone causes a rise of 23%, and methohexitone of nearly 40%, the rate remains constant in the etomidate series.

Adolescent

Mobile intensive care unit. Present conception and realisation.

A new Mobile Intensive Care Unit has been put in use at the "Service 900" of the Ministry of Health in Belgium. Its size was decided to enable efficient treatment of one patient. The type of suspension was chosen to give the patient adequate protection against untoward effects of travelling sickness. Radio-communication with the control center and hospital is ensured. The O2 supply-system provides an autonomy of 11 hours. Besides an electric distribution of 12 V. DC, a 220 V. AC is also available.

Ambulances