Figure 5. N-type (Cav2.2) calcium currents are
reduced by CBD3063 in DRG neurons . (A) Summary of bar graph showing the
normalized peak ICa2+ density after incubating sensory
neurons with DMSO (0.1%), 2, 20 and 50 μM of CBD3063. N=13-30 cells;
error bars indicate mean ± SEM; pp value as indicated;
Mann-Whitney test. (E) Boltzmann fits for voltage-dependent activation
and inactivation kinetics as shown. Half-maximal activation potential of
activation and inactivation (V1/2 ) and slope
values (k ) for activation and inactivation are presented inTable 2 . N=12-17 cells.
Furthermore, to test any off-target effects of CBD3063 we measured
current density–voltage curves and peak current densities for
Cav1 (L-type; Figure 6A, B ),
Cav2.1 (P/Q-type; Figure 6C, D ),
Cav2.3 (R-type; Figure 6E, F ), and
Cav3 (T-type; Figure 6G, H ) calcium channels.
We found that CBD3063 does not alter Ca2+ influx
through these channels when compared to cells treated with 0.1% DMSO.
When the voltage-dependence of activation and inactivation of these
channels was explored, we observed that CBD3063 did not alter these
parameters (Table 2 ). These findings show that CBD3063
selectively modulates the activity of N-type Ca2+channels.