Fig. 2

Enhanced Cell Survival in the Dorsal Dentate Gʹyrus Following Intranasal Co-administration of Galanin Receptor 2 and NPY1R Agonists in Adult Rats. 5-Bromo-2ʹ-deoxyuridine (BrdU) immunolabeling following intranasal administration of the Galanin 2 receptor agonist (M1145) and NPY1R receptor agonist, either singularly or in combination, with or without the GAL 2 receptor antagonist (M871). a, d Most BrdU-positive cells were situated in the granular cell layer (Gcl) of the dentate gyrus in the dorsal hippocampus, exhibiting round and regularly shaped BrdU-positive nuclei (Bregma: − 5.6 mm; as per Paxinos and Watson stereotaxic atlas, 2006). b Quantitative assessment of total BrdU-immunoreactive (IR) cells in the dentate gyrus of the dorsal hippocampus, after respective administrations of Control, M1145, NPY1R agonist [Leu31-Pro34]NPY, or co-administration of both agonists with or without M871. Data are presented as mean ± SEM. The co-administration of M1145 and the NPY1R agonist increased the number of BrdU-positive cells in the dorsal hippocampus compared to the effects of the individual peptides and the control group. However, this effect was nullified by the GALR2 antagonist M871. Statistical significance was determined through one-way ANOVA followed by Newman-Keuls post-hoc test, with *P < 0.05 vs M1145, NPY1R and M1145 + Y1R + M871; **P < 0.01 vs Control. d M1145 and NPY1R agonist intranasal co-administration notably increased BrdU immunolabeling in the Gcl compared to the control group c. Arrows in the figure indicate examples of BrdU positive neurons, while dashed lines delineate the Gcl of the dentate gyrus. e Quantification of BrdU-IR cells double-labeled with NeuN or DCX in either control or M1145 + Y1R-administered rats revealed that Y1R-GALR2 specifically induces neuronal maturation. Data are represented as mean ± SEM, with *P < 0.05 vs control according to Student’s unpaired t-test. f Representative photomicrograph illustrating BrdU + /NeuN + cells (indicated by white arrows) and BrdU-/NeuN + cells (indicated by white arrowheads) in the M1145 and NPY1R agonist group. Abbreviations: Control = Distilled water; M1145 = Galanin 2 receptor agonist 132 µg; Y1R = NPY1R receptor agonist [Leu31-Pro34]NPY 132 µg; M1145 + Y1R = Co-administration of M1145 and NPY1R; M1145 + Y1R + M871 = Co-administration of M1145, Y1R, and GALR2 antagonist M871 132 µg