(A) Images of P15 WT (Tmem67+/+) and hydrocephalic (Tmem67–/–) rats demonstrating enlarged horizontal and vertical cranial dimensions, and reduced BW compared with WT littermates. (B–D) Vertical and horizontal head dimensions, and BWs of normal (Tmem67+/+, Tmem67+/–) and hydrocephalic (Tmem67–/–) rats taken at P17 after 9 days of daily i.p. treatment with either vehicle, GSK101 (TRPV4 agonist), or HC067 (TRPV4 antagonist). (E) Kidney weights of animals, expressed as a function of BW, at P17 after 9 days of daily treatment with either vehicle, GSK101, or HC067, demonstrating no effect of the drugs on overt renal phenotype. Normal, vehicle (n = 4); normal, GSK101 (n = 3); normal, HC067 (n = 4). Hydro,vehicle (n = 17); hydro, GSK101 (n = 8); hydro, HC067 (n = 14). All data shown are the mean ± SEM for each group. Significance values were determined by 2-way ANOVA test in Prism using genotype and treatment as variables. Vehicle, DMSO/saline injection; GSK101, GSK1016790A, TRPV4 agonist, 0.003 mg/kg BW i.p. daily injection; HC067, HC067047, TRPV4 antagonist, 0.03 mg/kg BW i.p. daily injection.