Fig. 3. Anandamide/GPR55-induced Ca²⁺ signaling is linked to integrins. (A,B) The sensitivity of anandamide (10 µM) -triggered cytosolic Ca²⁺ signaling to various concentrations of extracellular Ca²⁺ (n=10), Ba²⁺ (n=24) and Sr²⁺ (n=31) was tested. (C) Comparison between the effect of 10 µM anandamide in Ca²⁺-containing buffer in the absence (n=20) or presence of 70 µM Mn²⁺ (n=40). (D) The effect of 10 µM anandamide on cytosolic free-Ca²⁺ concentration was monitored in the nominal Ca²⁺-free solution in the absence (n=25) or presence of the ROCK inhibitor Y27632 (10 µM, n=29). (E-G) The effects of antibodies (2 µM) against vβ3 integrin (LM609) (control, n=34; LM609, n=30) and the β1 (JB1A) (control, n=28; JB1A, n=33) and β3 subunits (B3A) (control, n=38; B3A, n=30) on cytosolic Ca²⁺ signaling induced by 10 µM anandamide was assessed in nominally Ca²⁺-free solution. (H) The effect of function-blocking β3-integrin antibody B3A on O1602 (10 µM) -initiated Ca²⁺ signaling in the presence of extracellular Ca²⁺ (control, n=65; B3A, n=84). Cytosolic free-Ca²⁺ concentrations were recorded using fura-2. ^*P<0.0001 versus the absence of the respective compound.