Ventral dentate gyrus is activated under GALR2 and the Y1R agonists intranasal infusion
The assessment of the successful delivery of M1145 and the Y1R agonists to the brain via the i.n. route was confirmed by c-fos induction. The i.n. administration of the Y1R agonist induced a significant increase in the number of c-fos-IR profiles in the granular region of the ventral dentate gyrus (one-way ANOVA, F4, 15 = 12.04, p < 0.001, Newman-Keuls post-hoc test: p<0.05) (Figure 1 a,b) compared with the control group. Conversely, the administration of the GalR2 agonist M1145 alone lacked effects on the numbers of c-fos positive cells (Figure 1 b) compared with the control group (Figure 1 b, c).
Furthermore, M114545 and Y1R agonist coinjection significantly increased the number of c-Fos-IR profiles in the granular region of the ventral dentate gyrus compared with the M1145 and the control groups (Newman-Keuls post-hoc test: p<0.001) and with the Y1R agonist alone group (Newman-Keuls post-hoc test: p<0.05) (Figure 1 b, d). The cotreatment with the GALR2 antagonist M871 specifically blocked this M1145 and Y1R agonists coadministration effects in the ventral dentate gyrus (Newman-Keuls post-hoc test: p<0.05) (Figure 1 b), indicating the participation of GALR2 in the Y1R-M1145 agonists interaction to stimulate c-fos induction.