Key result
Endogenous PYY and NPY induced significant mucosal antisecretory tone mediated by Y1 and Y2 receptors, and both contributed to tonic Y2-receptor-mediated inhibition of colonic transit.
Endogenous PYY and NPY induce significant mucosal antisecretory tone mediated by Y1 and Y2 receptors in both human and mouse colon.
Animal data on Y1/Y2-mediated colonic tone remain preclinical; leaves open human therapeutic translation.
BACKGROUND AND PURPOSE: Peptide YY (PYY) and neuropeptide Y (NPY) activate Y receptors, targets under consideration as treatments for diarrhoea and other intestinal disorders. We investigated the gastrointestinal consequences of selective PYY or NPY ablation on mucosal ion transport, smooth muscle activity and transit using wild-type, single and double peptide knockout mice, comparing mucosal responses with those from human colon. EXPERIMENTAL APPROACH: Mucosae were pretreated with a Y₁ (BIBO3304) or Y₂ (BIIE0246) receptor antagonist and changes in short-circuit current recorded. Colonic transit and colonic migrating motor complexes (CMMCs) were assessed in vitro and upper gastrointestinal and colonic transit measured in vivo. KEY RESULTS: Y receptor antagonists revealed tonic Y₁ and Y₂ receptor-mediated antisecretory effects in human and wild-type mouse colon mucosae. In both, Y₁ tone was epithelial while Y₂ tone was neuronal. Y₁ tone was reduced 90% in PYY⁻/⁻ mucosa but unchanged in NPY⁻/⁻ tissue. Y₂ tone was partially reduced in NPY⁻/⁻ or PYY⁻/⁻ mucosae and abolished in tetrodotoxin-pretreated PYY⁻/⁻ tissue. Y₁ and Y₂ tone were absent in NPYPYY⁻/⁻ tissue. Colonic transit was inhibited by Y₁ blockade and increased by Y₂ antagonism indicating tonic Y₁ excitation and Y₂ inhibition respectively. Upper GI transit was increased in PYY⁻/⁻ mice only. Y₂ blockade reduced CMMC frequency in isolated mouse colon. CONCLUSIONS AND IMPLICATIONS: Endogenous PYY and NPY induced significant mucosal antisecretory tone mediated by Y₁ and Y₂ receptors, via similar mechanisms in human and mouse colon mucosa. Both peptides contributed to tonic Y₂-receptor-mediated inhibition of colonic transit in vitro but only PYY attenuated upper GI transit.
No takes yet. Share an insight, caveat, or question.
Tough et al. (2011) studied this question. Y1 or Y2 receptor antagonists and PYY/NPY ablation vs. Wild-type mice and untreated mucosae was evaluated on Changes in short-circuit current, colonic transit, and colonic migrating motor complexes. Endogenous PYY and NPY induced significant mucosal antisecretory tone mediated by Y1 and Y2 receptors, and both contributed to tonic Y2-receptor-mediated inhibition of colonic transit.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: