Thio- und Oxybarbiturate hemmen die Dünndarmperistaltik. In vitro-Untersuchungen am
Meerschweinchenileum

Zusammenfassung

Fragestellung: Die Hemmung der Darmmotilität durch Anaesthetika und Pharmaka zur Analgosedierung von Patienten in der Intensivmedizin kann Ursache weiterer Komplikationen sein. Diese Studie untersucht, ob die Thio- und Oxybarbiturate Thiopental und Pentobarbital einen Einfluss auf die intestinale Peristaltik haben. Methodik: Dünndarmsegmente des Meerschweinchens wurden in vitro in einer Vorrichtung perfundiert, die propulsive Peristaltik ermöglicht. Durch Registrierung des intraluminalen Drucks kann die Schwelle (peristaltic pressure threshold, PPT), ab der peristaltische Kontraktionen ausgelöst werden, bestimmt werden. Thiopental und Pentobarbital (0,1 - 300 µM) wurden den Dünndarmsegmenten extraserosal zupipettiert und die Änderungen der PPT registriert. Ergebnisse: Weder das Lösungsmittel (physiologische Kochsalzlösung) noch Thiopental und Pentobarbital hatten in den Konzentrationen 0,1 µM - 10 µM einen Effekt auf die PPT. 30 µM Pentobarbital führte zu einem diskreten transienten Anstieg der PPT, der nach 100 µM Pentobarbital und Thiopental konzentrationsabhängig zunahm. Die Peristaltik aller Segmente kam bei einer Badkonzentration von 300 µM Thiopental und Pentobarbital völlig zum Erliegen (Thiopental EC₅₀ = 19,8 µM, Pentobarbital EC₅₀ = 99,7 µM). Der Austausch der Badlösung führte zur Wiederherstellung normaler Peristaltik. Schlussfolgerung: Aus den Untersuchungen wird gefolgert, dass Thiopental und Pentobarbital konzentrationsabhängig die Peristaltik des Meerschweinchendünndarms hemmen. Es wird angenommen, dass Barbiturate auch beim Menschen diese Wirkung auf die Darmmotilität haben.

Abstract

Introduction: Inhibition of gastrointestinal motility by drugs used for anaesthesia or sedation in critically ill patients in the ICU is a major problem leading to various complications. Thus this study examines whether the thio- and oxybarbiturates thiopentone and pentobarbitone exert an inhibitory effect on intestinal peristalsis. Methods: Peristalsis in isolated segments of the guinea-pig small intestine was elicited by distension of the gut wall through a rise of intraluminal pressure and recorded via the intraluminal pressure changes associated with the aborally moving peristaltic contractions. Thiopentone and pentobarbitone (0.1 - 300 µM)-induced inhibition of peristalsis was reflected by an increase of the peristaltic pressure threshold (PPT). Results: Thiopentone (EC₅₀ = 19,8 µM) and pentobarbitone (EC₅₀ = 99.7 µM) concentration-dependently increased the PPT. While the vehicle (saline) and 0.1 - 10 µM thiopentone and pentobarbitone were without any effect on the PPT, 100 µM caused a significant increase in PPT, and complete abolition of peristalsis occurred after 300 µM thiopentone or pentobarbitone in all segments tested. Inhibition was reversed by changing the bath solution. Conclusions: Thio- and oxybarbiturates inhibit intestinal peristalsis in the guinea-pig ileum. It is assumed that thiopentone and pentobarbitone affect propulsive peristalsis also in the human small intestine.

Schlüsselwörter

Barbiturate - Ileus - gastrointestinale Motilität - Intensivmedizin

Key words

Barbiturates - ileus - gastrointestinal motility - intensive care

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