Effects of placebo interventions on gastric motility and general autonomic activity.
OBJECTIVE
The study aimed to investigate placebo effects on gastric motility and to examine possible autonomic mediating mechanisms.


METHODS
Eighteen healthy volunteers received a placebo pill on three occasions together with the verbal suggestion that it would stimulate, relax, or not affect gastric activity. Electrogastrogram, electrocardiogram, and electrodermal activity recordings were conducted for 30 min prior to and following intervention.


RESULTS
Dominant frequency of the gastric slow wave decreased in the stimulant condition, and increased in the relaxant condition, the difference among conditions being significant. No differential effects of the interventions on cardiac interbeat intervals, heart rate variability, and skin conductance levels were observed.


CONCLUSIONS
Stomach relaxant and stimulant placebo interventions modulated gastric motility independently from changes in general autonomic activity.
Meissner
Karin
K
Institute of Medical Psychology, Ludwig-Maximilians University, Munich, Germany. karin.meissner@med.uni-muenchen.de
D000328:Adult; D000704:Analysis of Variance; D001341:Autonomic Nervous System / Q000187:drug effects*; D001944:Breath Tests; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D005712:Galvanic Skin Response / Q000187:drug effects; D005746:Gastric Emptying / Q000187:drug effects*; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D015990:Placebo Effect; D055815:Young Adult