Cell‐Specific Relations between Vasopressin and Renin‐Angiotensin‐Aldosterone Systems

Abstract

Vasopressin (AVP) is crucial for body water and electrolyte homeostasis. Its antidiuretic effects are mediated chiefly via renal V2 vasopressin receptors (V2R). Parallel activation of V1a and V1b receptors (V1aR and V1bR) may modulate the renin‐angiotensin‐aldosterone system (RAAS). Despite a large body of functional evidence for a crosstalk between AVP and RAAS, little is known about distribution of AVP receptors in RAAS‐related signalling. In this study we have comparatively analyzed V1aR, V1bR, and V2R distribution in the kidney, adrenal glands, and brain with focus on their potential role in modulation of RAAS.Custom antibodies to individual AVP receptors were generated and characterized using respective mouse knockout tissues. Distribution of the receptors was studied by immunofluorescence, immunocytochemistry and super resolution imaging using rodent and human tissues.The anti‐V1aR antibody produced signal in macula densa cells of the kidney, all three cortical zones of the adrenal glands, and suprachiasmatic and supraoptic nuclei of the hypothalamus. V1bR was detected in the mark of adrenal gland and hypothalamic nuclei but not in the kidney. V2R signal was observed along the distal nephron and principal cells of collecting duct cells of the kidney, but not in the adrenal glands or hypothalamus.In summary, our results document presence of V1aR and V1bR in hypothalamic nuclei and adrenal cortex which suggest their involvement in the release of adrenocorticotropic hormone and aldosterone. In addition, expression of V1aR in macula densa cells may affect renin release in a paracrine way.