Inhibitory Effects of Dexmedetomidine and Propofol on Gastrointestinal Tract Motility Involving Impaired Enteric Glia Ca 2+ Response in Mice

Propofol and dexmedetomidine are popular used for sedation in ICU, however, inadequate attention has been paid to their effect on gastrointestinal tract (GIT) motility. Present study aimed to compare the effect of propofol and dexmedetomidine on GIT motility at parallel level of sedation and explore the possible mechanism. Male C57BL/6 mice (8-10 weeks) were randomly divided into control, propofol and dexmedetomidine group. After intraperitoneal injection of propofol or dexmedetomidine, comparable sedative level was confirmed by sedative score, physiological parameters and electroencephalogram (EEG). Different segments of GIT motility in vivo (gastric emptying, small intestine transit, distal colon bead expulsion, stool weight and number of fecal pellets, gastrointestinal transit and whole gut transit time) and colonic migrating motor complexes (CMMCs) pattern in vitro were evaluated. The Ca2+ response of primary enteric glia was examined under the treatment of propofol or dexmedetomidine. There is little difference in physiological parameters and composite permutation entropy index (CPEI) between administration of 50 mg/kg propofol and 40 μg/kg dexmedetomidine, indicated that parallel level of sedation was reached. Data showed that propofol and dexmedetomidine had significantly inhibitory effect on GIT motility while dexmedetomidine was stronger. Also, the amplitude (ΔF/F0) of Ca2+ response in primary enteric glia was attenuated after treated with the sedatives while the effect of dexmedetomidine was greater than propofol. These findings demonstrated that dexmedetomidine caused stronger inhibitory effects on GIT motility in sedative mice, which may involve impaired Ca2+ response in enteric glia. Hence, dexmedetomidine should be carefully applied especially for potential GIT dysmotility patient.