EXPERIMENTAL PAIN IN THE STOMACH - A MODEL-BASED ON ELECTRICAL-STIMULATION GUIDED BY GASTROSCOPY

Background-Abdominal pain is often variable in intensity and difficult to characterise due to its referred pain pattern. Clinical pain is fu rthermore confounded by various emotional and cognitive factors. Aims- To develop and apply an experimental model to induce localised gastric pain. Subjects-Twelve healthy male volunteers. Methods-Stimulating el ectrodes were mounted on a biopsy forceps and electric stimuli were de livered during gastroscopy. Single, five repeated, and continuous stim uli were given at four locations in the stomach. Pain detection thresh olds and pain intensities were assessed together with localisation of the referred pain area. Results-Pain detection thresholds were higher in the prepyloric region compared with those obtained at the lesser an d greater curvature. Increasing stimulus intensity resulted in augment ed pain perception and repeated stimuli elicited pain at a lower stimu lus intensity than single stimuli. Continuous stimuli evoked constant (33%), increasing (33%), or decreasing (33%) pain. The localisation of referred pain varied considerably in the subjects. Conclusions-The mo del seems relevant to study basic pain mechanisms elicited by localise d stimuli in the stomach. The experimental data support the premise th at a gastric focus should always be suspected in patients referred wit h different kinds of abdominal pain.