Effects of a high-salt diet on TRPV-1-dependent renal nerve activity in Dahl salt-sensitive rats.
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.


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.


CONCLUSIONS
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.
Xie
Chaoqin
C
Wang
Donna H
DH
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002211:Capsaicin / Q000494:pharmacology; D007668:Kidney / Q000294:innervation* / Q000378:metabolism; D007682:Kidney Pelvis / Q000378:metabolism*; D008297:Male; D009475:Neurons, Afferent / Q000502:physiology*; D051381:Rats; D020303:Rats, Inbred Dahl; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D017673:Sodium Chloride, Dietary / Q000494:pharmacology*; D013373:Substance P / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism*; D014563:Urodynamics
D018040:Receptors, Neurokinin-1; D017673:Sodium Chloride, Dietary; D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat; D013373:Substance P; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin