These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Modulation of intestinal paracellular permeability by intracellular mediators and cytoskeleton.
    Author: Pérez M, Barber A, Ponz F.
    Journal: Can J Physiol Pharmacol; 1997 Apr; 75(4):287-92. PubMed ID: 9196854.
    Abstract:
    The influence of cytoskeletal inhibitors (cytochalasin E and colchicine) and intracellular mediators (cAMP, Ca2+, and protein kinase C) in the control of paracellular permeability to mannitol has been examined in rat jejunum in Ussing-type chambers. Cytoskeletal inhibitors, cytochalasin E (20 mumol.L-1) or colchicine (0.5 mmol.L-1), when present in mucosal, serosal, or in both mediums, significantly increase unidirectional mannitol fluxes. Exposure of mucosal and serosal intestinal surface to 10 mmol.L-1 theophylline or 1 mmol.L-1 cyclic AMP analogue for raising the intracellular cAMP enhances paracellular permeability. In Ca(2+)-free physiological medium passive permeability strongly increases. Alterations of cytosolic Ca2+ levels induced by the Ca2+ ionophore A23187 (20 mumol.L-1) or by 0.3 mmol.L-1 TMB-8, a Ca2+ releasing inhibitor from the intracellular stores, enhance mannitol flux. Addition of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate, which activates protein kinase C (PKC), also induces a large increase in the intestinal permeability to mannitol. These results provide evidence that tight junctions and consequently epithelial paracellular permeability can be physiologically controlled by intracellular mediators (Ca2+, cAMP, and PKC) probably through modulation of the cytoskeleton activity.
    [Abstract] [Full Text] [Related] [New Search]