Effect of acetic acid or trypsin application on rat colonic motility in vitro and modulation by two synthetic fragments of chromogranin A

Regul Pept. 2005 Jan 15;124(1-3):27-35. doi: 10.1016/j.regpep.2004.06.022.


The hypothesis that Chromogranin A (CgA)-derived peptides are involved in mechanisms modulating altered colonic motility was tested. Rat distal colonic strips were studied using an organ bath technique. Acetic acid (AA)-induced effects were characterized on spontaneous mechanical activities (SMA) in the presence of CgA4-16 or CgA47-66. In preparations with mucosa, AA induced a transient hyperactivity followed by a decrease in tone. The first phase is sensitive to tetrodotoxin (TTX) and capsaicin. The second phase was sensitive to BAYK8644 but insensitive to L-nitro-arginine-methyl-ester (L-Name)/apamin together. CgA4-16 or CgA47-66 alone produced no change on SMA. The administration of CgA4-16 prior to AA increased the duration of the excitatory component and reduced tone inhibition. CgA47-66 prior to AA only decreased duration of the excitatory phase. In preparations without mucosa, AA decreased tone. This effect was sensitive to BAYK8644 and CgA4-16. Trypsin decreased basal tone. This effect was suppressed by TTX, BAYK8644 or L-Name/apamin and were reduced by CgA4-16. AA-induced effects on rat colonic motility in vitro may be mediated through activation of primary afferents and an action at L-Type calcium channels. CgA-derived peptides are shown to decrease AA-induced effects on motility.

MeSH terms

  • Acetic Acid / pharmacology*
  • Animals
  • Chromogranin A
  • Chromogranins / chemical synthesis*
  • Chromogranins / chemistry
  • Chromogranins / pharmacology*
  • Colon / drug effects*
  • Colon / physiology
  • Gastrointestinal Motility / drug effects*
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / physiology
  • Male
  • Peptide Fragments / chemical synthesis*
  • Peptide Fragments / chemistry
  • Peptide Fragments / pharmacology*
  • Rats
  • Rats, Wistar
  • Trypsin / pharmacology*


  • Chromogranin A
  • Chromogranins
  • Peptide Fragments
  • chromofungin
  • chromogranin A (4-16)
  • Trypsin
  • Acetic Acid