Fig. 4

G protein modulation of Cav2.2-37a and Cav2.2-37b channels following activation of mMOR1, mMOR1C and mMOR1O. a Representative set of Cav2.2-37a currents in the presence of mMOR1C, recorded before or after the application of 10 μM DAMGO. As outlined in the Results section, P1 represents the first current in each trace evoked by a test depolarization to + 10 mV, P2 is the second inward current in a given trace evoked by a 10 mV test depolarization (P2) preceded by a strong depolarizing prepulse (PP, note that the pre-pulse-evoked outward current is not shown in the figure). Relief of Gβγ modulation by the pre-pulse is observed by the increase in current amplitude seen during P2 in the presence of DAMGO. b Percentage of peak current inhibition (during P1) of Cav2.2e-37a currents after application of 10 μM DAMGO. c Percentage of peak current inhibition (during P1) of Cav2.2e-37b currents after application of 10 μM DAMGO. d Voltage dependent pre-pulse facilitation measured in the presence of DAMGO in tsA-201 cells expressing Cav2.2-37a channels with mMOR1, mMOR1C or mMOR1O. The data points reflect the current evoked by test pulse P2 normalized to the current evoked by test pulse P1. e Voltage dependent pre-pulse facilitation measured in the presence of DAMGO in tsA-201 cells expressing Cav2.2-37b channels with mMOR1, mMOR1C or mMOR1O. The data points reflect the current evoked by the test pulse P2 normalized to the current evoked by test pulse P1. The number of cells recorded are indicated in parentheses, asterisks denote significance at the *0.05, **0.01, and ***0.001 levels (unpaired Wilcoxon test)