Fig. 7. Blocking L-type voltage-dependent Ca²⁺ channels attenuated γ-aminobutyric acid (GABA)-induced increases of [Ca²⁺]_i.

(A) Ca²⁺ responses induced by GABA (200 μm, 10 s) or muscimol (50 μm, 10 s) in a GABA(Ca+) neuron during the day before and after nimodipine (20 μM) application. Both GABA- and muscimol-induced Ca²⁺ transients were attenuated. (B) Nimodipine attenuated GABA- and muscimol-induced Ca²⁺ transients in GABA(Ca+) neurons. Data are the mean ± SEM of the area under the curve (AUC; Ca²⁺ ratio/s over 0-10 s of GABA treatment) for GABA(Ca+) (n = 30, t₂₉ = 6.03 GABA, t₂₉ = 10.6 muscimol, ***P < 0.00001) SCN neurons.