Differential Desensitisation of Afferent Nerve Fibres by Iberis amara (STW 6) and Iberogast (STW 5) in the Murine Colon

Spontaneous afferent discharge was not different among the subgroups. STW 6 reduced afferent nerve discharge following 5-HT administration to 0.2 ± 0.2 imp seca？？1 compared to 3.0 ± 1.0 imp seca？？1 following STW 5 and 5.0 ± 2.0 imp seca？？1 in vehicle controls (p<0.05 STW 6 vs. vehicle). There was no difference in the response to bradykinin after addition of STW6 (36.0 ± 5.0 imp sec-1) and vehicle (38.0 ± 6.0 imp seca？？1), respectively, while this was reduced to 9.0 ± 2.0 imp seca？？1 following STW 5 (p<0.05 compared to vehicle). Afferent discharge to luminal ramp distension up to 80 cmH2O was reduced following STW 5 and STW 6 pre-treatment compared to vehicle (p<0.05). At high-threshold distension pressures a more pronounced reduction was observed following STW 5.