However, the increased TRPV4 current amplitudes and [Ca2+]i signals were paralleled by increased immunostaining for TRPV4 in astrocytes in the CA1 region of the hippocampus, thereby suggesting that the elevation in protein expression could account, at least partially, for the up-regulation of the TRPV4-mediated [Ca2+]i signals observed after ischemia. The gene discussed is TRPV4; the disease is ischemia.