In vivo regulation of mucosal transport of H+ and HCO3- in the feline gall bladder.
In the gall bladder of a fasting subject, a decline in the pH of the contents occurs due to secretion of H+ from the mucosa. In this study in anaesthetized cats, the gall bladder lumen was perfused with a bicarbonate buffer bubbled with 4% CO2 in air. During basal conditions, the PCO2 always rose while the pH and [HCO3-] fell in the buffer when passing through the gall bladder lumen, indicating a continuous secretion of H+ by the mucosa. This H+ secretion was enhanced by stimulation of the respective sympathetic nerves and was blocked by intraluminal amiloride. Intravenous infusion of vasoactive intestinal peptide (VIP) raised the pH and [HCO3-] in the buffer during the passage through the gall bladder lumen, indicating a secretion of bicarbonate from the mucosa. In view of the presence of sympathetic and VIP immunoreactive nerve fibres in the gall bladder wall and VIP receptors on the luminal epithelial cells, the study demonstrates that there are functional grounds for physiological variations in the secretion of H+ and HCO3- by the gall bladder mucosa. These variations may be important for the solubility of calcium salts in the gall bladder contents.
Nilsson
B
B
Department of Surgery, University of Göteborg, Sahlgrenska Hospital, Sweden.
Rådberg
G
G
Friman
S
S
Thune
A
A
Svanvik
J
J
D000584:Amiloride / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000032:analysis / Q000493:pharmacokinetics*; D001646:Bile / Q000737:chemistry; D001692:Biological Transport / Q000502:physiology; D002415:Cats; D005215:Fasting; D005260:Female; D005704:Gallbladder / Q000737:chemistry / Q000294:innervation / Q000502:physiology*; D006859:Hydrogen / Q000032:analysis / Q000493:pharmacokinetics*; D006863:Hydrogen-Ion Concentration; D007262:Infusions, Intravenous; D008297:Male; D009092:Mucous Membrane / Q000294:innervation / Q000502:physiology / Q000648:ultrastructure; D010477:Perfusion; D018005:Receptors, Vasoactive Intestinal Peptide / Q000032:analysis / Q000502:physiology; D013153:Splanchnic Nerves / Q000502:physiology; D014660:Vasoactive Intestinal Peptide / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology
D001639:Bicarbonates; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D000584:Amiloride; D006859:Hydrogen