Stability of the vasopressin V2 receptor–adenylyl cyclase system in rat kidney

From vasopressin receptor to water channel: intracellular traffic, constraint and by-pass

“…An isolated nephron segment study indicated that the sensitivity of the medullary thick ascending limb of the loop of Henle to VP was reduced (Imbert-Teboul et al 1978). Treatment of BDI rats with dDAVP is not associated with any clear increase in total kidney adenylyl cyclase activity, either basal or VP-stimulated (Bia et al 1979, Shen et al 1998, although in situ cyclic AMP content of the renal papilla is significantly higher in VP-or dDAVP-treated rats Figure 2 The likely sequence of intracellular events associated with the renal V 2 receptor-adenylyl cyclase-aquaporin system in the absence of VP (i.e. central diabetes insipidus), or in the presence of a V 2 receptor antagonist.…”

“…BDI rats lacking circulating VP have similar G s mRNA to normal parent strain LE rats, but have reduced G i mRNA expression particularly G i-1 and G i-3 . Furthermore, treatment of BDI rats with the V 2 agonist dDAVP is associated with increases in G i mRNA expression, with G i-2 and G i-3 being particularly affected, but again no effect on G s (Shen et al 1998). In the same study administration of a V 2 receptor antagonist to normal Sprague-Dawley rats produced small decreases in G i-1 and G i-2 mRNA expression only.…”

“…The receptor binding in the kidneys of these VP-deficient animals is reduced by 30% (Rajerison et al 1977) and V 2 receptor mRNA is also lower by approximately 30% ) compared with normal rats of the parent Long Evans (LE) strain, which is a more appropriate control (Valtin 1982) than the heterozygotes which fail to show significant differences (Shewey & Dorsa 1986). Furthermore, treatment of BDI rats with the V 2 receptor agonist dDAVP results in an approximate 30% increase in mRNA for the V 2 receptor (Shen et al 1998), restoring receptor levels to those seen in LE rats. Because of the wide-ranging effects of VP other defects are also found in this strain.…”

“…In renal tissue of BDI rats mRNA expression of AC4, AC5, AC6 and AC9 was reduced compared with LE rats . Treatment of BDI rats with the V 2 agonist dDAVP resulted in an increase in the mRNA for AC5, AC6 and AC9, although AC4 mRNA decreased further (Shen et al 1998). Treatment of normal rats with a specific V 2 receptor antagonist was associated with slight reductions in mRNA for AC5, AC6 and AC9, although AC4 mRNA actually increased slightly, compared with untreated controls (Shen et al 1998).…”

“…Therefore, it is possible that the reduction in V 2 receptor numbers and the increase seen in response to VP treatment may be associated with any of these, or other, associated defects. It would appear that this is unlikely, because normal Sprague-Dawley rats treated with a specific non-peptidergic V 2 antagonist resulting in a urinary dilution also showed a small reduction in V 2 receptor mRNA (Shen et al 1998). Nevertheless, the possibility that the lack of VP during embryonic development may alter the adult phenotype needs to be borne in mind.…”