Effects of octreotide on esophageal visceral perception and cerebral evoked potentials induced by balloon distension

Objective: Octreotide, a somatostatin analog, is antinociceptive and increa ses perception threshold in the rectum, The aim of this study was to determ ine whether octreotide alters esophageal sensory thresholds and cortical ev oked potentials (CEPs) resulting from intraesophageal balloon distension. M ethods: Twelve healthy volunteers (six men and sis women, median age 25 yr, range 21-60 Sr) underwent a randomized, double-blind, placebo-controlled t rial of octreotide 100 mu g s.c. versus saline. A 30-mm balloon was inserte d 5 cm above the lower esophageal sphincter without topical anesthesia. The balloon nas inflated at a rate of 170 cc/s to a maximum of 30 cc in 2 cc s teps. Both pressure and volume were recorded. Patients reported first sensa tion (S1) and maximally tolerated pain (S2), Two cycles were performed both preinjection and 40 min postinjection. Evoked potentials were recorded fro m Cz to linked ears over 50 balloon inflation cycles (volume = S2), Results : Threshold volume to first sensation (SI) was significantly increased afte r octreotide injection [median (interquartile range): 24 (14-26) cc vs 13 ( 9-21) cc, p < 0.02], No significant alteration in volume causing pain (S2) was noted after octreotide injection [29 (25-30+) cc vs 2 2 (19-29) cc]. Ne ither were volumes causing either first sensation [18 (11-24) cc vs 13 (9-1 8) cc] or pain [27 (23-30) cc vs 23 (21-25) cc] significantly altered by pl acebo injection. Neither amplitude nor latency of any of the three peaks of the evoked potential recordings differed significantly between postplacebo and postoctreotide recordings. Conclusion: Octreotide significantly increa sed esophageal perception thresholds to balloon distension. It did not alte r pain thresholds, nor were cortical evoked potentials to painful stimulati on altered in normal subjects. (C) 1999 by Am. Cell. of Gastroenterology.