The transient receptor potential (TRP) vanilloid 4 (TRPV4) member of the TRP superfamily has recently been implicated in numerous physiological processes. In this study, we describe a small molecule TRPV4 channel activator, (N-, which we have used as a valuable tool in investigating the role of TRPV4 in the urinary bladder. GSK1016790A elicited Ca 2ϩ influx in mouse and human TRPV4-expressing human embryonic kidney (HEK) cells (EC 50 values of 18 and 2.1 nM, respectively), and it evoked a dose-dependent activation of TRPV4 whole-cell currents at concentrations above 1 nM. In contrast, the TRPV4 activator 4␣-phorbol 12,13-didecanoate (4␣-PDD) was 300-fold less potent than GSK1016790A in activating TRPV4 currents. TRPV4 mRNA was detected in urinary bladder smooth muscle (UBSM) and urothelium of TRPV4 ϩ/ϩ mouse bladders. Western blotting and immunohistochemistry demonstrated protein expression in both the UBSM and urothelium that was absent in TRPV4 Ϫ/Ϫ bladders. TRPV4 activation with GSK1016790A contracted TRPV4 ϩ/ϩ mouse bladders in vitro, both in the presence and absence of the urothelium, an effect that was undetected in TRPV4 Ϫ/Ϫ bladders. Consistent with the effects on TRPV4 HEK whole-cell currents, 4␣-PDD demonstrated a weak ability to contract bladder strips compared with GSK1016790A. In vivo, urodynamics in TRPV4 ϩ/ϩ and TRPV4 Ϫ/Ϫ mice revealed an enhanced bladder capacity in the TRPV4 Ϫ/Ϫ mice. Infusion of GSK1016790A into the bladders of TRPV4 ϩ/ϩ mice induced bladder overactivity with no effect in TRPV4 Ϫ/Ϫ mice. Overall TRPV4 plays an important role in urinary bladder function that includes an ability to contract the bladder as a result of the expression of TRPV4 in the UBSM.Transient receptor potential (TRP) vanilloid 4 (TRPV4), a member of the TRP superfamily of cation channels, has been implicated in a number of physiological processes, including osmoregulation (Liedtke and Friedman, 2003;Mizuno et al., 2003), hearing (Tabuchi et al., 2005), thermal and mechaniThis work was supported by GlaxoSmithKline Pharmaceuticals. Article, publication date, and citation information can be found at

SB-525334 (6-[2-tert-butyl-5-(6-methyl-pyridin-2-yl)-1H-imidazol-4-yl]-quinoxaline) has been characterized as a potent and selective inhibitor of the transforming growth factor-␤1 (TGF-␤1) receptor, activin receptor-like kinase (ALK5). The compound inhibited ALK5 kinase activity with an IC 50 of 14.3 nM and was ϳ4-fold less potent as an inhibitor of ALK4 (IC 50 ϭ 58.5 nM). SB-525334 was inactive as an inhibitor of ALK2, ALK3, and ALK6 (IC 50 Ͼ 10,000 nM). In cell-based assays, SB-525334 (1 M) blocked TGF-␤1-induced phosphorylation and nuclear translocation of Smad2/3 in renal proximal tubule cells and inhibited TGF-␤1-induced increases in plasminogen activator inhibitor-1 (PAI-1) and procollagen ␣1(I) mRNA expression in A498 renal epithelial carcinoma cells. In view of this profile, SB-525334 was used to investigate the role of TGF-␤1 in the acute puromycin aminonucleoside (PAN) rat model of renal disease, a model of nephritis-induced renal fibrosis. Orally administered doses of 1, 3, or 10 mg/kg/day SB-525334 for 11 days produced statistically significant reductions in renal PAI-1 mRNA. Also, the compound produced dose-dependent decreases in renal procollagen ␣1(I) and procollagen ␣1(III) mRNA, which reached statistical significance at the 10-mg/kg/day dose when compared with vehicle-treated PAN controls. Furthermore, PAN-induced proteinuria was significantly inhibited at the 10-mg/kg/day dose level. These results provide further evidence for the involvement of TGF-␤1 in the profibrotic changes that occur in the PAN model and for the first time, demonstrate the ability of a small molecule inhibitor of ALK5 to block several of the markers that are predictive of fibrosis and renal injury in this model.

Oxidative and inflammatory stresses are cardinal in the pathogenesis of hypertension and atherosclerosis. Oxidative stress also leads to the induction of inflammation through the activation of proinflammatory transcription factors. Understanding the mechanisms leading to oxidative stress and the means of suppressing it are important in controlling complications related to atherogenesis, since oxidative and inflammatory stress are important in the pathogenesis of atherosclerosis. The failure of chemical antioxidants [which scavenge reactive oxygen species (ROS)], such as vitamins E and C, has led to further exploration of the ROS-suppressive effects of drugs used in the treatment of cardiovascular disease. Carvedilol has been shown to possess both ROS-scavenging and ROS-suppressive effects, and its use is associated with a reduction in oxidative stress. Furthermore, anti-inflammatory effects of carvedilol have now been described. Although further clinical investigations are required, these properties may contribute to the improvement in clinical outcomes observed with carvedilol.

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SUMMARY To investigate a possible sex difference in the development of deoxycorticosterone (DOC)-salt hypertension in rats, systolic blood pressure was measured over 6 weeks in unilaterally nephrectomized male and female rats with or without DOC-salt treatment. Throughout the treatment, systolic blood pressure was significantly lower in female than in male DOC-salt rats (at the end of the sixth week: 190 ± 8 vs 163 ± 7 nun Hg, p < 0.05). The difference in blood pressure was also confirmed by the direct measurement of mean arterial pressure at the end of the experiment. The 24-hour urinary excretion of vasopressin was significantly higher in male control rats than in female control rats; however, no difference was observed between male and female DOC-salt rats, in which the urinary excretion of vasopressin was four to five times higher than in control rats. The plasma vasopressin concentration was higher in DOC-salt rats, but there were no differences between sexes. These were no differences in the metabolic clearance rate of vasopressin among the four groups of rats. This indicates that the elevated plasma vasopressin concentration in DOC-salt hypertensive rats is due to increased release of the hormone, rather than to impaired metabolism. Thus, although vasopressin plays a pivotal role in the pathogenesis of DOC-salt hypertension, the sexual dimorphism in this form of hypertension cannot be attributed to differences in the secretion, metabolism, or plasma concentration of vasopressin. (Hypertension 9: 172-177, 1987) KEY WORDS • deoxycorticosterone-salt hypertension metabolic clearance rate sex difference • vasopressin T HE lower incidence of hypertension in women before menopause than in men is an established epidemiological observation. 12 It has also been reported that in some genetic models of hypertension, such as spontaneously hypertensive rats 3 -4 and Dahl salt-sensitive rats, 5 the female is less hypertensive than the male rat. The mechanisms responsible for this sex difference have not been elucidated, but involvement of the gonadal hormones seems likely, since gonadectomy and treatment with gonadal steroids can influence the course of the hypertension in these genetic models.3 " 7In the present study, we investigated the question of whether there is sexual dimorphism in the develop- Received May 19, 1986; accepted August 19, 1986. ment of deoxycorticosterone (DOC)-salt hypertension in the rat. This issue has not, to our knowledge, been systematically investigated. Furthermore, since vasopressin is a prerequisite for the development and maintenance of this form of hypertension, 8 " 10 and since recent evidence" indicates that vasopressin secretion is higher in normotensive male than in female rats, experiments also were designed to determine whether any differences in the development of DOC-salt hypertension between male and female rats are accompanied by differences in the rate of secretion or metabolism of vasopressin. Materials and Methods Experiment 1Twenty male and 20 female 5-week-old Sp...