Fig. 1.

Haloperidol increases the mRNA (a, b) and protein (c, d) levels of σ1R (b, d) and type 1 (a, c), but not type 2 (e) and 3 (f), IP₃ receptors in differentiated NG-108 cells (Dif). In contrast to non-differentiated (ND) cells (a, b striped columns), in differentiated cells (a, b black columns) haloperidol at a concentration of 10 nmol/L (low-dose; Hn) increases the mRNA expression of IP₃R1, and at a concentration of 10 µmol/L (high-dose; Hμ), the mRNA and protein expression of both IP₃R1 and σR1 was increased (a, b). Type 2 IP₃ receptors are not expressed in NG-108 cells (e); we observed an expression signal in PC12 cells but not in NG-108 cells. The mRNA expression of type 3 IP₃ receptors was not changed in undifferentiated or in differentiated cells following Hμ treatment (f). The results are expressed as the mean ± SEM. Statistical significance: **p < 0.01 and ***p < 0.0001 compared to control untreated cells