Fig. 5
Exogenous 2-AG mildly reduces meningeal nerve endings nociceptive firing. A Example traces of APs recorded from the peripheral part of the rat trigeminal nerve within control, i.e. during the 1-min active phase of the 1st KCl pulse and the corresponding phase of the 2nd KCl pulse when also 10 µM 2-AG was present. Note the slight decrease of general nociceptive firing that was obtained during the combined application. B Time courses of spike frequency (10-s bin size) induced by paired pulses of KCl and 1 µM Capsaicin as control (data of the top panel in Fig. 4B) and during the combined application of 10 µM 2-AG with the 2nd KCl pulse (bottom panel). C No difference was observed for the number of APs induced when comparing a ratio of the 5-min windows before/after application of 2-AG (N=6) to the same windows of the ratio spontaneous spiking activity in the control condition (Cntr, N = 7; data representation from Fig. 4B). D 2-AG application significantly reduced the number of APs during the 1-min active phase of the 2nd KCl pulse compared to that of the 1st KCl pulse. The ratio of APs (between 2nd and 1st (taken as 100%) KCl pulse) in the control (Cntr, N = 8; data representation from Fig. 4C) condition resulted higher than in the presence of 2-AG (N = 6, Mann Whitney test, * = 0.02). E No difference was observed for the number of APs during the 1-min active phase of 1 µM Capsaicin of the control condition (Cntr, N = 7; data representation from Fig. 4D) and after application of 2-AG (N=6)