It is unclear whether endogenous serotonin release is involved in the regulation of gastric motility and food intake.
To study the effect of acute administration of the selective serotonin reuptake inhibitor citalopram on gastric motor function in man.
Nineteen healthy volunteers underwent a gastric barostat, gastric emptying and/or a drinking test after dosing with either placebo or citalopram (20 mg intravenously). In the barostat protocol, a flaccid bag was introduced in the stomach and inflated at intra-abdominal pressure +2 mmHg, volume was recorded before and after administration of a liquid meal (300 kcal). Gastric emptying for solids and liquids was simultaneously assessed using the ¹⁴C-octanoic acid/¹³C-glycine breath test. During the drink test, volunteers drank at a rate of 15 mL/min until maximal satiation. Citalopram was compared with placebo using t-tests and mixed model analysis.
Citalopram induced a significant preprandial gastric relaxation (volume increase of 154 ± 55 mL vs. -38 ± 33 mL after placebo dosing; P < 0.05), whereas the postprandial volume increase was significantly decreased after citalopram treatment (F₁₂.₈₀ = 4.78, P < 0.0001; maximum volume increase was 304 ± 40 vs. 201 ± 54 mL after placebo and citalopram treatment respectively). Citalopram enhanced solid (123 ± 17 vs. 77 ± 6 min, P < 0.05) but not liquid emptying (62 ± 6 vs. 57 ± 4 min). Satiation scores during the drink test were lower after citalopram (F₁₉.₁₅₃ = 2.02, P = 0.01; volunteers drank 998 ± 129 vs. 765 ± 79 mL after citalopram and placebo treatment respectively).
The observed effects indicate a role for serotonin in the control of gastric motility and food intake.