Figure 4.

CPMs in Mrgprd ^−/− mice exhibit decreased heat sensitivity. Sharp electrode recordings were made from WT (black), Mrgprd ^+/+ (white), and Mrgprd ^−/− (gray) CPM cells that were tested for their response to heat stimuli. A, B, Compared with WT and Mrgprd ^+/+ strains, the average thermal threshold of CPMs in Mrgprd ^−/− mice showed decreased excitability in terms of a higher heat threshold (A; degrees Celsius) and a lower peak instantaneous frequency (B; hertz). C, A heat ramp from 31 to 52°C showed a significant reduction in the average spikes per second in Mrgprd ^−/− mice between the temperatures of 43 and 52°C. Significance (*p < 0.05) is indicated below Mrgprd ^−/− in relation to both WT and Mrgprd ^+/+.