Interaction between endothelin and angiotensin II in the up-regulation of vasopressin messenger RNA in the inner medullary collecting duct of the rat.

Recent studies in our laboratory have demonstrated that angiotensin (ANG) II and endothelin (ET) 1 up-regulate the expression of arginine vasopressin V(2) receptor in the inner medullary collecting duct (IMCD) of the rat. The present studies were performed to explore the interaction between ANG II and ET-1 in up-regulating the expression of arginine vasopressin V(2) receptor in the IMCD of the rat. Two sets of studies were done.

Endothelin upregulates the expression of vasopressin V2 mRNA in the inner medullary collecting duct of the rat.

Recent studies in our laboratory have demonstrated that bosentan, a mixed endothelin ET(A)/ET(B) receptor antagonist, prevented the upregulation of the arginine vasopressin (AVP) V(2) receptor in the inner medullary collecting duct (IMCD) of cardiomyopathic hamsters. These results suggested that endothelin-1 (ET-1) is involved in the upregulation of AVP V(2) receptors. Studies were performed to detect the effect of ET-1 on the expression of AVP V(2) receptors and the ET receptor mediating these effects within the IMCD of the rat.

Attenuation of renal vasopressin V2 receptor upregulation by bosentan, an ETA/ETB receptor antagonist.

Circulating endothelin (ET) levels are elevated in heart failure and positively correlated with severity of heart failure. Recent studies demonstrated arginine vasopressin (AVP) V2 mRNA expression was upregulated in the inner medullary collecting duct (IMCD) of cardiomyopathic hamsters (CM). The goal of the present studies was to determine if ET-1 is involved in upregulating the expression of AVP V2 mRNA in the IMCD of CM by using a mixed ETA/ETB receptor antagonist bosentan.

Regulation of aquaporin-4 in a traumatic brain injury model in rats.

Object: Aquaporin-4 (AQP4) plays a significant role in the regulation of brain water homeostasis. In this study the authors investigated the regulation of AQP4 following a focal cortical contusion injury in rats.

Methods: Thirty-three adult male Wistar rats received a focal cortical contusion of the parietal cortex.

Angiotensin II upregulates the expression of vasopressin V2 mRNA in the inner medullary collecting duct of the rat.

Previous in vivo studies in cardiomyopathic hamsters suggested that the expression of vasopressin (AVP) V2 mRNA is up- regulated by angiotensin II. The present study was performed to determine whether angiotensin II plays a role in regulating the expression of AVP V2 mRNA and aquaporin-2 (AQP2) mRNA in the inner medullary collecting duct (IMCD) of the male Wistar rat. The expression of AVP V2 mRNA and AQP2 mRNA in the IMCD was measured by competitive reverse-transcriptase polymerase chain reaction (RT-PCR).

Upregulation of vasopressin V2 and aquaporin 2 in the inner medullary collecting duct of cardiomyopathic hamsters is attenuated by enalapril treatment.

Previous studies showed that aquaporin 2 (AQP2) is elevated in the kidney of the heart failure rat suggesting that an increased amount of AQP2 contributes to water retention in heart failure. We performed the present study to determine whether angiotensin II play a role in causing an increase in the expression of arginine vasopressin (AVP) V2 and AQP2 mRNA in the kidney of the cardiomyopathic hamster. The expression of AVP V2 and AQP2 mRNA in the inner medullary collecting duct (IMCD) was measured by competitive reverse transcriptase-polymerase chain reaction (RT-PCR) before and after treatment with an angiotensin-converting enzyme inhibitor, enalapril.