Inhibition of 5-hydroxytryptamine re-uptake impairs human gall-bladder emptying.
BACKGROUND
5-Hydroxytryptamine (5-HT) is an important neurotransmitter in the enteric nervous system. The intrinsic neural plexus of the gall-bladder resembles the enteric nervous system and similarly contains 5-HT neurones. The action of 5-HT on gallbladder motility has been investigated in animals but its effect on the human gall-bladder in vivo is unknown.


METHODS
The effect of indirect 5-HT agonism using paroxetine, a specific inhibitor of neuronal 5-HT reuptake, on gall-bladder motility was investigated in 12 healthy volunteers. In a randomized double-blind crossover design, gall-bladder motility was assessed after administration of 30 mg paroxetine daily for two days and after placebo. Ultrasonography was used to determine gall-bladder volumes while fasting and at 5 min intervals following a 250 kcal mixed liquid meal.


RESULTS
Fasting gall-bladder volumes of 21.8 +/- 3.2 ml on placebo and 28.0 +/- 3.5 ml on paroxetine were similar. Paroxetine impaired postprandial gall-bladder emptying. Residual gall-bladder volume was 10.2 +/- 2.7 ml with placebo and 17.1 +/- 2.7 ml with paroxetine (P < 0.05). Ejection fraction was 57.3 +/- 7.7% on placebo and 40.9 +/- 4.7% on paroxetine (P < 0.05).


CONCLUSIONS
5-HT pathways may participate in the regulation of biliary motility, and this study demonstrates an inhibitory role of 5-HT in the control of human gall-bladder emptying.
Gorard
D A
DA
Department of Gastroenterology, St. Bartholomew's Hospital, London, UK.
Healy
J C
JC
O'Donnell
L J
LJ
Farthing
M J
MJ
D000328:Adult; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004435:Eating; D005215:Fasting; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging / Q000187:drug effects*; D016473:Gallbladder Emptying / Q000187:drug effects*; D006801:Humans; D008297:Male; D017374:Paroxetine / Q000494:pharmacology*; D014463:Ultrasonography
D017374:Paroxetine