Vasopressin Receptor Regulation in Maintaining Potassium Homeostasis in a Sus scrofa Model of Hemorrhagic Shock
Abstract
We previously showed that elevated potassium (K)levels seen with severe hemorrhage appear to stimulate enhanced vasopressin(VP) release, and that in turn, elevated VP levels help correct hyperkalemia by increasing renal tubular K secretion. We thus tested whether brain VP receptors controlling vasopressin release were regulated synergistically with kidney VP receptors whichmodulated renal K excretion. We hypothesized that brain VP receptor up‐regulation may enable positive feedback for K‐stimulated augmentation of VP responsiveness in hemorrhage, and that renal VP receptor expression would reflect VP receptor mediated action on renal K excretion. Thus, in anesthetized Yorkshire cross pigs (n=35) we compared plasma VP (pVP) and plasmaK (pK) before, at the end of hemorrhage (30 ml/kg over 20 minutes), and after resuscitation, against mRNA expression of V1aR, V1bR, and V2R receptors in brain and kidney tissues collected after resuscitation. Multiple regression analysis showed that increased pVP at the end of hemorrhage positively correlated (p<0.05) with expression of V1aR and V1bR in the hypothalamus, V1bR in the anterior pituitary, and V2R in the renal cortex. Plasma K levels at the end of resuscitation were negatively correlated (p<0.05) with renalcortex V2R expression. In a different group of control animals that did not undergo hemorrhage, pVP and pK remained unchanged throughout. Results suggest that an up‐regulation of V1a and V1b receptors in the brain contributed to an amplified VP response in hemorrhage. In addition, VP appears to stimulate renal V2R expression to lower pK levels and maintain K homeostasis via a renal V2R‐mediated negative feedback mechanism.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 01, 2016
- Source ID
- 10.1096/fasebj.30.1_supplement.962.1
Entities
People
- Catherine F. T. Uyehara
- Claudia A. Hernandez
- Joy Sarkar
- Lauren N Kajiura
- Lee‐ann M. Murata
- Michael R Rowland
- Sara A Wong
- Wayne M. Ichimura
Organizations
- Tripler Army Medical Center
- United States Army Medical Research and Development Command