TRPV4 and ischemia: In control astrocytes and those 1H after H/I, mainly an increased frequency of [Ca2+]i transients was observed, while 7 days following ischemia we also detected sustained Ca2+ entry after 4αPDD application in 57% of astrocytes, which was completely blocked by Ca2+-free extracellular solution (Fig. 3); however, it was insensitive to the specific TRPV4 inhibitor RN1734 (Fig. 4).