We have recently demonstrated that elevation of [Ca2+]i following P2X receptor (P2XR) activation in renal vascular smooth muscle cells (RVSMCs) is initiated as an abrupt sub-plasmalemmal (PM) [Ca2+]i upstroke (SPCU) [1], which depends on both, Ca2+ entry through P2XRs and voltage-gated Ca2+ channels (VGCCs), and Ca2+ release from the sarcoplasmic reticulum (SR) activated via Ca2+-induced Ca2+ release (CICR) mechanism [2]. Here we analysed: (1) role of P2XRs and VGCCs in activation of the SR Ca2+ release, (2) recruitment of ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP3Rs) in CICR, (3) expression of genes encoding RyR and IP3R subtypes and (4) spatial distribution of RyRs and IP3Rs in RVSMCs. RVSMCs were isolated from arcuate and interlobular arteries of rat kidney, as previously described [3]. RT-PCR analysis was performed on single RVSMCs 5×(~500 per sample) collected under microscope. Changes of [Ca2+]i in fluo-4-loaded RVSMCs were visualised using fast x-y confocal imaging. Data are expressed as mean ± S.E.M. The data groups were compared using Student’s t-test (statistical significance at P<0.05). We found that RVSMCs express IP3R type 1 and RyR type 2. IP3Rs dominate in sub-PM SR, while RyRs dominate in deeper SR elements. SPCU depended on αβ-meATP concentration (EC50=0.18±0.01 µmol/L). Block of RyRs (100 µmol/L ryanodine) reduced the SPCU amplitude by only 18±4% (n=7) and had no significant effect on time-to-peak (P=0.08). The effect of IP3R inhibition (30 µmol/L 2-APB) was significantly stronger: reduction of the amplitude by 48±6% and increase of the time-to-peak by 98±15% (n=10). The effect of calcium store depletion (50 µmol/L CPA) was also significantly stronger than that of RyR inhibition: reduction of the amplitude by 53±3% and increase of the time-to-peak by 51±10% (n=22). The effect of simultaneous block of RyRs and IP3Rs was similar to the effect of calcium store depletion: reduction of the amplitude by 60±4% and increase of the time-to-peak by 48±11% (n=12). Block of VGCCs (5 µmol/L nicardipne) reduced the amplitude by 39±2% and increased time-to-peak by 81±11% (n=18). Block of VGCCs following calcium store depletion reduced the amplitude by 70±3% and decreased time-to-peak by 21±8% (n=20). When VGCCs were initially blocked, the calcium store depletion decreased the SPCU by only 23±5% (n =8). Similarly, inhibition of IP3Rs under these condition decreased the SPCU by only 16±4% (n=12). We conclude that depolarization of RVSMC following P2X receptor activation induces IP3R-mediated Ca2+ release from sub-PM SR, which is activated mainly by Ca2+ entry via VGCCs. This fundamental mechanism provides convergence of signalling pathways engaged in electromechanical and pharmacomechanical coupling in vascular smooth muscle.