Alpha1-adrenoceptors down-regulate ClC-2 chloride channels in epithelial cells from the acutely denervated jejunum.
Acute sympathetic denervation of the small intestine up-regulates alpha1-adrenoceptors on villus enterocytes and activation of these alpha1-adrenoceptors inhibits chloride secretion. We tested whether alpha1-adrenoceptor-mediated inhibition of chloride secretion was the result of reduced ClC-2 chloride channel expression. Phorbol myristate acetate (PMA) (a protein kinase C (PKC) activator) had no effect on ClC-2 levels. In contrast, alpha1-adrenoceptor activation significantly decreased ClC-2 protein levels in both the villus (1.58+/-0.19 to 0.75+/-0.19 arbitrary units) and crypt (1.69+/-0.15 to 0.37+/-0.23 arbitrary units) epithelial cells from the acutely denervated jejunum but not innervated controls. These data suggest that inhibition of chloride secretion following alpha1-adrenoceptor activation in the acutely denervated small intestine may be through ClC-2 down-regulation.
Baglole
Carolyn J
CJ
Gastrointestinal Research Group, University of Calgary, 3330 Hospital Drive, Calgary, Alberta, Canada T2N 4N1. carolyn_baglole@urmc.rochester.edu
Sigalet
David L
DL
Meddings
Jonathan B
JB
D000818:Animals; D017763:Autonomic Denervation; D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels / Q000032:analysis*; D015536:Down-Regulation; D007413:Intestinal Mucosa / Q000737:chemistry* / Q000166:cytology; D007583:Jejunum / Q000294:innervation*; D008297:Male; D010766:Phosphorylation; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D011917:Rats, Inbred Lew; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*
D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; D018340:Receptors, Adrenergic, alpha-1; D011493:Protein Kinase C