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Fig. 3 | BMC Research Notes

Fig. 3

From: Modulation of CaV1.3b L-type calcium channels by M1 muscarinic receptors varies with CaVβ subunit expression

Fig. 3

D2Rs and M1Rs inhibit recombinant N-current demonstrating successful expression of both GPCRs. To demonstrate that D2Rs are functional, HEK-M1 cells were transfected with the D2R, CaV2.2, α2δ1, and a CaVβ subunit plasmids using the same conditions as described in the Methods section and in Additional file 1 legend as described for CaV1.3b. a Time course of CaV2.2-β3 current inhibition by 0.5 μM quin added at time 0 with (filled circles, n = 8, P < 0.001 compared to CTL) or without (open circles, n = 3) co-transfection of D2Rs. b Concentration–response curve of quin on CaV2.2-β3 current (n = 3–5). c Time course of CaV2.2-β3 current inhibition by Oxo-M added at time 0 under CTL conditions (filled circles, n = 5, P < 0.001 compared to CTL) or preincubation for at least 3 min with 10 μM of the PLA2 antagonist, OPC (open circles, n = 5, P < 0.05 compared to Oxo-M alone, ANOVA). d Time course of CaV2.2-β3 current inhibition by 10 (filled triangles) or 50 nM (filled circles) quin under control conditions or preincubated with OPC (open symbols) (n = 1–5). e Representative CaV2.2-β2a currents measured at a test potential of + 20 mV (−PP) from a holding potential of − 90 mV. A 25 ms prepulse to + 120 mV was placed before a second test pulse (+PP) to measure for membrane-delimited inhibition. CTL current (black) or 30 s after application of 0.5 μM quin (grey). f Same as e in the presence of 1 mg/ml BSA. g Time course of CaV2.2-β2a current (−PP, filled circles; +PP, open circles) exposed to 0.5 μM quin at time 0 for 1 min. After washing, current fully recovered; BSA was added for 3 min before addition of BSA/quin. h Summary of CaV2.2-β2a inhibition by quin (n = 9) or BSA/quin (n = 3)

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