Abstract
Peptide YY (PYY) is a powerful inhibitor of intestinal secretion mediated by cAMP agonists such as vasoactive intestinal peptide and prostaglandin E2. We hypothesized that PYY would attenuate the secretory diarrhea in piglet cryptosporidiosis, which is mediated by prostaglandins E2 and I2. Control and infected ileal tissues from piglets were studied in Ussing chambers. The addition of PYY to the serosal bathing solution abolished net Cl− secretion in infected tissue. The inhibitory effect of PYY was eliminated with the prostaglandin synthesis inhibitor indomethacin and with the nerve conduction blocker tetrodotoxin. PYY completely blocked the antiabsorptive and secretory effects of the prostaglandin I2 analog carbacyclin, which has previously been shown to operate through enteric nerve pathways in this tissue. In contrast, PYY had no inhibitory effect on the secretory responses induced by prostaglandin E2 or vasoactive intestinal peptide. Results suggest that the antisecretory effects of PYY are mediated by inhibition of prostaglandin I2 induction of enteric nerves. Thus, PYY may play an important role in moderating the secretory diarrhea in cryptosporidiosis.
Footnotes
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Send reprint requests to: Dr. Robert A. Argenzio, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606.
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↵1 This work was supported by United States Department of Agriculture Grant 94–37204-0448.
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↵2 R. A. Argenzio, M. Armstrong, A. Blikslager and J. M. Rhoads, unpublished observations.
- Abbreviations:
- TTX
- tetrodotoxin
- VIP
- vasoactive intestinal peptide
- PG
- PG
- G
- conductance
- Isc
- short circuit current
- Jsm
- flux from serosa to mucosa
- Jms
- flux from mucosa to serosa
- Jnet
- net flux
- PYY
- peptide YY, NPY, neuropeptide Y
- Received March 14, 1997.
- Accepted July 2, 1997.
- The American Society for Pharmacology and Experimental Therapeutics
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