Relationship of cytochrome P450 pharmacogenetics to the effects of yohimbine on gastrointestinal transit and catecholamines in healthy subjects

A. E. Bharucha, Todd Skaar, C. N. Andrews, M. Camilleri, S. Philips, B. Seide, D. Burton, K. Baxter, A. R. Zinsmeister

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Alpha-2 adrenergic receptors tonically inhibit colonic motility and the α2-adrenergic antagonist yohimbine, given intravenously, increased colonic tone in humans. However, the effect of yohimbine on colonic transit in humans is unknown. In this study, 30 healthy volunteers were randomized to yohimbine 16.2 mg p.o. t.i.d. or identical placebo for 7 days. We evaluated gastric emptying, small intestinal, and colonic transit by scinitigraphy, bowel habits, haemodynamics and plasma catecholamines. As cytochrome P450 enzymes metabolize yohimbine, P450 genotypes (CYP2D6 and CYP3A4) were determined in 25 of 30 subjects who consented to genetic studies. The relationship between drug metabolizer status predicted by CYP2D6 and CYP3A4 and effects of yohmibine were assessed. Compared to placebo, yohimbine increased (P ≤ 0.02) diastolic blood pressure, plasma noradrenaline concentrations and maximum tolerated volume during the satiation test [yohimbine (1241 ± 88, mean ± SEM) vs placebo (1015 ± 87), P = 0.054]. However, yohimbine did not affect gastrointestinal transit. Based on CYP2D6 and CYP3A4 alleles, seven and 18 subjects were, respectively, extensive (EM) and poor (PM) metabolizers of yohimbine. Compared to EM, PM of yohimbine had a greater increase in plasma noradrenaline (P = 0.1 for PM vs EM), lower maximum tolerated volumes (1120 ± 95 vs 1484 + 131 mL, P = 0.02), and faster colonic transit (i.e. GC24 was 3.0 ± 0.4 vs 2.1 ± 0.5, P = 0.1). These data suggest that CYP2D6 and CYP3A4 genotypes which determine the metabolism of yohimbine may influence its sympathetic and gastrointestinal effects.

Original languageEnglish
Pages (from-to)891-899
Number of pages9
JournalNeurogastroenterology and Motility
Volume20
Issue number8
DOIs
StatePublished - Aug 2008

Fingerprint

Gastrointestinal Transit
Yohimbine
Pharmacogenetics
Cytochrome P-450 Enzyme System
Catecholamines
Healthy Volunteers
Cytochrome P-450 CYP3A
Cytochrome P-450 CYP2D6
Placebos
Norepinephrine
Adrenergic alpha-2 Receptors
Genotype
Satiation
Blood Pressure
Adrenergic Antagonists
Gastric Emptying
Habits
Hemodynamics
Alleles

Keywords

  • Adrenergic
  • Catecholamines
  • Colon
  • Cytochrome P450
  • Gastrointestinal transit
  • Yohimbine

ASJC Scopus subject areas

  • Physiology
  • Gastroenterology
  • Neuroscience(all)

Cite this

Relationship of cytochrome P450 pharmacogenetics to the effects of yohimbine on gastrointestinal transit and catecholamines in healthy subjects. / Bharucha, A. E.; Skaar, Todd; Andrews, C. N.; Camilleri, M.; Philips, S.; Seide, B.; Burton, D.; Baxter, K.; Zinsmeister, A. R.

In: Neurogastroenterology and Motility, Vol. 20, No. 8, 08.2008, p. 891-899.

Research output: Contribution to journalArticle

Bharucha, A. E. ; Skaar, Todd ; Andrews, C. N. ; Camilleri, M. ; Philips, S. ; Seide, B. ; Burton, D. ; Baxter, K. ; Zinsmeister, A. R. / Relationship of cytochrome P450 pharmacogenetics to the effects of yohimbine on gastrointestinal transit and catecholamines in healthy subjects. In: Neurogastroenterology and Motility. 2008 ; Vol. 20, No. 8. pp. 891-899.
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