Key result
A high-salt diet in Dahl salt-sensitive rats impaired TRPV1-mediated increases in afferent renal nerve activity and release of substance P and CGRP compared to other groups.
Why the study?
Does a high-salt diet impair TRPV1-dependent renal nerve activity in Dahl salt-sensitive rats?
Does a high-salt diet impair TRPV1-dependent renal nerve activity in Dahl salt-sensitive rats?
A high-salt diet suppresses TRPV1-mediated renal nerve activity and neuropeptide release in Dahl salt-sensitive rats, suggesting a mechanism for salt-sensitive hypertension.
No immediate clinical implications; leaves open TRPV1 modulation as a hypothesis for human salt-sensitive hypertension.
OBJECTIVE: To test the hypothesis that transient receptor potential vanilloid type 1 channel (TRPV1)-mediated increases in afferent renal nerve activity (ARNA) and release of substance P (SP) and calcitonin gene-related peptide (CGRP) from the renal pelvis are suppressed in Dahl salt-sensitive (DS), but not -resistant (DR), rats fed a high-salt (HS) diet. METHODS AND RESULTS: Male DS and DR rats were given a HS or low-salt (LS) diet for 3 weeks. Perfusion of capsaicin (CAP, 10(-6)M), a selective TRPV1 agonist, into the left renal pelvis increased ipsilateral ARNA in all groups, but with a smaller magnitude in DS-HS compared to other groups. CAP increased contralateral urine flow in all groups except DS-HS rats. CAP-induced release of SP and CGRP from the renal pelvis was less in DS-HS compared to other groups. Western blot showed that TRPV1 expression in the kidney decreased while expression of neurokinin 1 receptors increased in DS-HS compared to other groups. CONCLUSION: TRPV1-mediated increases in ARNA and release of SP and CGRP in the renal pelvis are impaired in DS rats fed a HS diet, which can likely be attributed to suppressed TRPV1 expression in the kidney and contributes to increased salt sensitivity.
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Xie et al. (2010) studied Salt sensitivity. High-salt diet vs. Low-salt diet was evaluated on TRPV1-mediated increases in afferent renal nerve activity (ARNA) and release of substance P and CGRP. A high-salt diet in Dahl salt-sensitive rats impaired TRPV1-mediated increases in afferent renal nerve activity and release of substance P and CGRP compared to other groups.
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