FIGURE 7.

AMPH- and METH-mediated [Ca²⁺]_i increase is derived from thapsigargin-sensitive internal stores, not CdCl₂-sensitive plasma membrane calcium channels. A, representative experiment showing incubation of DAT-expressing cells with 2 μm thapsigargin (TG) eliminated the Ca²⁺ response induced by both AMPH and METH; n = 30–57 cells recorded in 2–3 independent experiments for each condition. B and C are representative experiments showing the presence of a non-subtype selective Ca²⁺ channel blocker (2 mm CdCl₂) had no impact on METH-mediated increases (B, n = 106 in four independent experiments) or AMPH-mediated increases (C, n = 57 in three independent experiments) in internal free Ca²⁺ ([Ca²⁺]_i). Solid arrows indicate addition of the stimulants. Values were normalized to the average basal values ([Ca²⁺]_b) for each independent experiment.