Extracellular matrix (ECM) modulates the phenotype of airway smooth muscle cells (ASM) (Hirst SJ, et al, 2000). Capacitative calcium entry (CCE), responsible for the control of relaxation and contraction of ASM is thought to be coded by TRP channel genes. Although studies have shown some links between ECM and CCE, direct effects of ECM on CCE in HASM are still not fully understood. The purpose of the present study was to elucidate the interplay between ECM and CCE in cultured human ASM (HASM) and underlying mechanisms with emphasis on TRPC genes. HASM cells were isolated from resection tissue from patients undergoing pneumonectomy (ethical approval was obtained from the LREC of the City Hospital of Nottingham). Cells (passage 2 to 5) were transferred onto 96 well plates or glass cover slips pre-coated with Collagen -1 (Col-1), fibronectin (FN) or laminin (LN) (10μg/mL). Fluo-4 was used to measure intracellular Ca²⁺ on confluent monolayers and whole-cell patch clamp to study CCE currents induced by CPA (10 μM). Experiments were performed in serum-free DMEM in the presence of cycloheximide (10 μM) to inhibit new protein synthesis. Taqman Real-time PCR to assess TRPC1, TRPC3, TRPC4 and TRPC6 gene expression was carried out on cDNA samples prepared from HASM cells growing on plates pre-coated with FN, Col-1 or LN. Data were analysed by ANOVA or unpaired t test as appropriate. CPA-induced Ca²⁺release and CCE in cells growing on LN were increased by 25% (n=9, p<0.01) compared with responses in cells grown on Col-1 or FN. CPA-induced currents were nearly abolished by 1 mM concentrations of La³⁺, Ni²⁺, and Gd³⁺, and decreased in a concentration-dependent manner by La³⁺ (0.01 to 100 μM). SKF93635 (up to 100 μM) was without any effect. Compared with control, peak SOCC currents at -100 mV were decreased by 66% (n=9, p<0.01), and 71% (n=10, p<0.05) respectively in FN, Col-1 treated cells while in LN treated cells peak SOCC current was increased by 67% (n=10, p <0.05). Compared with control, TRPC1 and TRPC3 gene expression were not significantly affected by Col-1, FN or LN treatment. TRPC4 was up-regulated by 31% and 70% in Col-1 and FN treated cells respectively while in LN treated cells TRPC4 was down-regulated by 25%. TRPC6 gene expression was up-regulated by 97% in FN-treated cells. In the present study, we have shown that FN and Col-1 down-regulated CCE while exposure to LN protein produced a small up-regulation of CCE in cultured HASM. Matrix factors also regulated TRPC gene expression: in general an increase in TRPC6 expression was associated with a decrease in CCE. These results suggest that alterations in the matrix environment induce changes in calcium handling by HASM cells: this may account in part for altered responsiveness of asthmatic airways.