Effects of venlafaxine, buspirone, and placebo on colonic sensorimotor functions in healthy humans.
OBJECTIVE
We have shown that venlafaxine-XR, a serotonin (5-HT) and norepinephrine reuptake inhibitor, enhanced gastric accommodation, whereas buspirone, a 5-HT(1A) receptor agonist, reduced postprandial symptoms after a fully satiating meal. Our aim was to compare the effects of venlafaxine, buspirone, and placebo on colonic sensorimotor functions in healthy adults.


METHODS
In this randomized, double-blind, parallel-group, placebo-controlled trial of 60 healthy adults, we assessed the effects of oral venlafaxine, 150 mg; buspirone, 20 mg; and placebo on colonic sensorimotor functions.


RESULTS
Venlafaxine increased colonic compliance relative to placebo; thus it decreased the intracolonic balloon pressure at half-maximum volume (P = 0.001) and altered the overall shape of the compliance curve, beta (P = 0.01). Venlafaxine also decreased fasting colonic tone (P = 0.02) and the tonic response to a meal (P = 0.003) compared with placebo; no differences in high amplitude phasic contractile events were observed. Pressure thresholds for first sensation (P = 0.1) and gas (P = 0.07) were not statistically significant with venlafaxine. The increase in pain scores per unit pressure during phasic distentions were affected by treatment (P = 0.02), with smallest changes on venlafaxine and highest on placebo. Buspirone did not significantly alter colonic compliance, tone, or sensation relative to placebo.


CONCLUSIONS
Venlafaxine alters colonic compliance and tone, and tends to reduce sensation during colonic distention in healthy humans. These data support the need for further clinical and physiologic studies of venlafaxine in colonic disorders affecting motor and possibly sensory functions.
Chial
Heather J
HJ
Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.) Program, Mayo Clinic, Rochester, Minnesota 55905, USA.
Camilleri
Michael
M
Ferber
Irene
I
Delgado-Aros
Silvia
S
Burton
Duane
D
McKinzie
Sanna
S
Zinsmeister
Alan R
AR
D000328:Adult; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D018687:Antidepressive Agents, Second-Generation / Q000494:pharmacology*; D002065:Buspirone / Q000494:pharmacology*; D003106:Colon / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D003187:Compliance; D003511:Cyclohexanols / Q000494:pharmacology*; D004311:Double-Blind Method; D005215:Fasting; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain; D019518:Postprandial Period; D011312:Pressure; D012016:Reference Values; D012684:Sensory Thresholds; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D000069470:Venlafaxine Hydrochloride
D014151:Anti-Anxiety Agents; D018687:Antidepressive Agents, Second-Generation; D002065:Buspirone; D003511:Cyclohexanols; D017366:Serotonin Receptor Agonists; D017367:Selective Serotonin Reuptake Inhibitors; D000069470:Venlafaxine Hydrochloride