TY - JOUR
T1 - Role of Connexin40 in the autoregulatory response of the afferent arteriole
AU - Sørensen, Charlotte Mehlin
AU - Giese, Isaiah
AU - Braunstein, Thomas Hartig
AU - Brasen, Jens Christian
AU - Salomonsson, Max
AU - von Holstein-Rathlou, Niels-Henrik
PY - 2012/9/15
Y1 - 2012/9/15
N2 - Connexins in renal arterioles affect autoregulation of arteriolar tonus and renal blood flow and are believed to be involved in the transmission of the tubuloglomerular feedback (TGF) response across the cells of the juxtaglomerular apparatus. Connexin40 (Cx40) also plays a significant role in the regulation of renin secretion. We investigated the effect of deleting the Cx40 gene on autoregulation of afferent arteriolar diameter in response to acute changes in renal perfusion pressure. The experiments were performed using the isolated blood perfused juxtamedullary nephron preparation in kidneys obtained from wildtype or Cx40 knockout mice. Renal perfusion pressure was increased in steps from 75 to 155 mmHg, and the response in afferent arteriolar diameter was measured. Hereafter, a papillectomy was performed to inhibit TGF, and the pressure steps were repeated. Conduction of intercellular Ca2+ changes in response to local electrical stimulation was examined in isolated interlobular arteries and afferent arterioles from wild-type or Cx40 knockout mice. Cx40 knockout mice had an impaired autoregulatory response to acute changes in renal perfusion pressure compared with wild-type mice. Inhibition of TGF by papillectomy significantly reduced autoregulation of afferent arteriolar diameter in wild-type mice. In Cx40 knockout mice, papillectomy did not affect the autoregulatory response, indicating that these mice have no functional TGF. Also, Cx40 knockout mice showed no conduction of intercellular Ca2+ changes in response to local electrical stimulation of interlobular arteries, whereas the Ca2+ response to norepinephrine was unaffected. These results suggest that Cx40 plays a significant role in the renal autoregulatory response of preglomerular resistance vessels.
AB - Connexins in renal arterioles affect autoregulation of arteriolar tonus and renal blood flow and are believed to be involved in the transmission of the tubuloglomerular feedback (TGF) response across the cells of the juxtaglomerular apparatus. Connexin40 (Cx40) also plays a significant role in the regulation of renin secretion. We investigated the effect of deleting the Cx40 gene on autoregulation of afferent arteriolar diameter in response to acute changes in renal perfusion pressure. The experiments were performed using the isolated blood perfused juxtamedullary nephron preparation in kidneys obtained from wildtype or Cx40 knockout mice. Renal perfusion pressure was increased in steps from 75 to 155 mmHg, and the response in afferent arteriolar diameter was measured. Hereafter, a papillectomy was performed to inhibit TGF, and the pressure steps were repeated. Conduction of intercellular Ca2+ changes in response to local electrical stimulation was examined in isolated interlobular arteries and afferent arterioles from wild-type or Cx40 knockout mice. Cx40 knockout mice had an impaired autoregulatory response to acute changes in renal perfusion pressure compared with wild-type mice. Inhibition of TGF by papillectomy significantly reduced autoregulation of afferent arteriolar diameter in wild-type mice. In Cx40 knockout mice, papillectomy did not affect the autoregulatory response, indicating that these mice have no functional TGF. Also, Cx40 knockout mice showed no conduction of intercellular Ca2+ changes in response to local electrical stimulation of interlobular arteries, whereas the Ca2+ response to norepinephrine was unaffected. These results suggest that Cx40 plays a significant role in the renal autoregulatory response of preglomerular resistance vessels.
U2 - 10.1152/ajprenal.00026.2012
DO - 10.1152/ajprenal.00026.2012
M3 - Journal article
C2 - 22811484
SN - 1931-857X
VL - 303
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
IS - 6
ER -