Thio- and oxybarbiturates inhibit peristalsis in the Guinea-pig ileum in vitro

Abstract

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. 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 microM)-induced inhibition of peristalsis was reflected by an increase of the peristaltic pressure threshold (PPT). Thiopentone (EC50 = 19,8 microM) and pentobarbitone (EC50 = 99.7 micro M) concentration-dependently increased the PPT. While the vehicle (saline) and 0.1 - 10 micro M thiopentone and pentobarbitone were without any effect on the PPT, 100 micro M caused a significant increase in PPT, and complete abolition of peristalsis occurred after 300 micro M thiopentone or pentobarbitone in all segments tested. Inhibition was reversed by changing the bath solution. 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.