“Woah! It's like Spotify but for academic articles.”

Instant Access to Thousands of Journals for just $40/month

Adrenergic activation of electrogenic K+ secretion in guinea pig distal colonic epithelium: desensitization via the Y2-neuropeptide receptor

Adrenergic activation of electrogenic K+ secretion in guinea pig distal colonic epithelium: desensitization via the Y2-neuropeptide receptor Abstract Adrenergic activation of electrogenic K + secretion in isolated mucosa from guinea pig distal colon was desensitized by peptide-YY (PYY). Addition of PYY or neuropeptide-Y (NPY) to the bathing solution of mucosae in Ussing chambers suppressed the short-circuit current ( I sc ) corresponding to electrogenic Cl − secretion, whether stimulated by epinephrine (epi), prostaglandin-E 2 (PGE 2 ), or carbachol (CCh). Neither peptide markedly inhibited the large transient component of synergistic secretion (PGE 2 + CCh). Sustained Cl − secretory I sc was inhibited ∼65% by PYY or NPY, with IC 50 s of 4.1 ± 0.9 nM and 9.4 ± 3.8 nM, respectively. This inhibition was eliminated by BIIE0246, an antagonist of the Y2-neuropeptide receptor (Y2-NpR), but not by Y1-NpR antagonist BVD10. Adrenergic sensitivity for activation of K + secretion in the presence of Y2-NpR blockade by BIIE0246 was (EC 50 s) 2.9 ± 1.2 nM for epi and 13.3 ± 1.0 nM for norepinephrine, approximately fourfold greater than in the presence of PYY. Expression of mRNA for both Y1-NpR and Y2-NpR was indicated by RT-PCR of RNA from colonic mucosa, and protein expression was indicated by immunoblot. Immunoreactivity (ir) for Y1-NpR and Y2-NpR was distinct in basolateral membranes of columnar epithelial cells in the crypts of Lieberkühn as well as intercrypt surface epithelium. Adrenergic nerves in proximity with crypts were detected by ir for dopamine-β-hydroxylase, and a portion of these nerves also contained NPY ir . BIIE0246 addition increased secretagog-activated I sc , consistent with in vitro release of either PYY or NPY. Thus PYY and NPY were able to suppress Cl − secretory capacity and desensitize the adrenergic K + secretory response, providing a direct inhibitory counterbalance against secretory activation. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AJP - Gastrointestinal and Liver Physiology The American Physiological Society

Loading next page...

You're reading a free preview. Subscribe to read the entire article.

And millions more from thousands of peer-reviewed journals, for just $40/month

To be the best researcher, you need access to the best research

  • With DeepDyve, you can stop worrying about how much articles cost, or if it's too much hassle to order — it's all at your fingertips. Your research is important and deserves the top content.
  • Read from thousands of the leading scholarly journals from Springer, Elsevier, Nature, IEEE, Wiley-Blackwell and more.
  • All the latest content is available, no embargo periods.

Stop missing out on the latest updates in your field

  • We’ll send you automatic email updates on the keywords and journals you tell us are most important to you.
  • There is a lot of content out there, so we help you sift through it and stay organized.