[Role of adenosine in the digitalis action on atrio-ventricular conduction in the dog heart]. / Participación de la adenosina en la acción digitalica sobre la conducción auriculo-ventricular del corazón canino.

In order to explore the hypothesis about the existence of an adenylic component on ouabain effects on the atrioventricular node, we perform experiments on anesthetized and vagotomized dogs. Decremental propagation of impulses through atrioventricular conduction system was evaluated stimulating the right atria at frequencies from 3.5 to 5.0 per second. Aminophylline antagonized and dipyridamole synergized the atrioventricular decremental conduction induced by digitalis. The blockade of purinergic receptors produced by aminophylline and the inhibition of adenosine endocytosis by dipyridamole could explain these antagonic and synergistic interaction with ouabain, and constitute an experimental evidence favorable to the possibility of the existence of a purinergic component on the digitalis mechanism of action.

[A tiapride and ketamine combination in short duration anesthesia]. / Asociación de tiapride y ketamina en anestesia de corta duración.

Tiapride was used as premedication on a series of 16 patients subsequently submitted to general anesthesia with ketamine. In order to compare the effects of tiapride on the incidence of visionary dreams, hallucinations and dyslepsic syndrome brought about by, this series was compared with 2 further series of patients premedicated with dihydrobenzoperidol plus fentanyl (15 patients) and diazepam plus haloperidol (11 patients). Effectiveness was evaluated by means of a 10 point recovery scale (1: rate of sedation; 2: anterior amnesia; 3: comprehensiveness and collaboration test; 4: space sense and time orientation; 5: Bender test; 6: dysleptic syndrome; 7: sick feeling and vomit; 8: subjective status; 9: recovery quality; 10: dreams and hallucinations) at 15, 30 and 60 minutes after the administration of the different premedications. General tolerance was evaluated by continuous quantification of vital signs: pulse rate, EKG and systolic, diastolic and mean blood pressures. The effects were analysed with ANOVA one-way, Newman-Keuls and t-paired tests. Premedication with 7.5 mg/kg of tiapride significantly reduced the incidence of dreaming, provided the necessary sedation and appropiate postoperative analgesia and rapid recovery of psychomotor coordination with no obvious alterations in haemodynamic parameters attributable to the selective blocking action of the dopaminergic receptors. The association tiapride-ketamine may be useful in anesthesia for day-case surgery.