Figure 2
Intraperitoneal administration of atropine blocked Substance P (SP)-induced suppression of CA1 population spike (PS) in anaesthetised animals. SP (2 µg/µl, 0.5 µl) was microinjected into the MS 4 times (SP1, SP2, SP3, SP4) with at least 1 h between microinjections. The animals were injected intraperitoneally (i.p.) with vehicle or atropine (5 mg/kg) half an hour prior to SP2 and SP3 microinjections. Time course plots and histograms are built as in Fig. 1. (a) Composite of microinjection sites in the MS, built as in Fig. 1. (b, d) Time course graphs illustrating the effect of systemic administration of vehicle (b) or atropine (d) on the suppression of CA1 PS induced by intra-MS SP. (c, e) Histogram illustrating the average amplitude of PS in first 5 min after microinjection expressed as a percentage of the control PS amplitude (average of PS amplitude in − 2 and − 1 min). Note that administration of atropine (d, e), but not vehicle (b, c), blocked the suppression induced by microinjection of SP into the MS. Data are mean ± S.E.M. Significant difference (p < 0.05): (d) #Atropine i.p + SP2 MS vs. SP1, *SP4 MS vs. SP1 MS; two-way RM ANOVA followed by Bonferroni post-hoc test. (e) *vs.SP1 MS; one-way ANOVA followed by Newman–Keuls post-hoc test.
