• Anandamide;
  • piperine;
  • capsazepine;
  • primary afferent neurones;
  • vanilloid receptors;
  • cannabinoid receptors;
  • capsaicin;
  • intestinal motility
  • We have studied the effect of capsaicin, piperine and anandamide, drugs which activate vanilloid receptors and capsazepine, a vanilloid receptor antagonist, on upper gastrointestinal motility in mice.

  • Piperine (0.5 – 20 mg kg−1 i.p.) and anandamide (0.5 – 20 mg kg−1 i.p.), dose-dependently delayed gastrointestinal motility, while capsaicin (up to 3 mg kg−1 i.p.) was without effect. Capsazepine (15 mg kg−1 i.p.) neither per se affected gastrointestinal motility nor did it counteract the inhibitory effect of both piperine (10 mg kg−1) and anandamide (10 mg kg−1).

  • A per se non effective dose of SR141716A (0.3 mg kg−1 i.p.), a cannabinoid CB1 receptor antagonist, counteracted the inhibitory effect of anandamide (10 mg kg−1) but not of piperine (10 mg kg−1). By contrast, the inhibitory effect of piperine (10 mg kg−1) but not of anandamide (10 mg kg−1) was strongly attenuated in capsaicin (75 mg kg−1 in total, s.c.)-treated mice.

  • Pretreatment of mice with NG-nitro-L-arginine methyl ester (25 mg kg−1 i.p.), yohimbine (1 mg kg−1, i.p.), naloxone (2 mg kg−1 i.p.), or hexamethonium (1 mg kg−1 i.p.) did not modify the inhibitory effect of both piperine (10 mg kg−1) and anandamide (10 mg kg−1).

  • The present study indicates that the vanilloid ligands anandamide and piperine, but not capsaicin, can reduce upper gastrointestinal motility. The effect of piperine involves capsaicin-sensitive neurones, but not vanilloid receptors, while the effect of anandamide involves cannabinoid CB1, but not vanilloid receptors.

British Journal of Pharmacology (2001) 132, 1411–1416; doi:10.1038/sj.bjp.0703975