Figure 3.
5-HT2CR Agonist-Induced Improvement in Glucose Tolerance Is Associated with MC4R-Dependent Increased FOS-IR in IML ChAT Neurons
Brains from 12 hr dark-cycle-fasted wild-type (WT) and Mc4r KO littermates (n = 18; body weight range = 26–55 g) pretreated with saline or mCPP (1 mg/kg, i.p.) 45 min preceding a glucose bolus (1 g/kg, i.p.) were processed for immunohistochemistry.
(A) FOS-IR was not evident in the intermediolateral nucleus of the spinal cord (IML) following saline treatment.
(B) Magnification of boxed area in (A).
(C–F) In contrast, FOS-IR was consistently evident in mCPP-pretreated WT mice (C and D), but not in Mc4r KO mice (E and F).
(G–I) Subsequent analysis revealed that a substantial percentage of FOS-IR-positive neurons (H) (green fluorescent nuclear stain) were ChAT-IR positive (I) (red fluorescent cytoplasmic stain). (G) shows a merged and higher-magnification image of (H) and (I). White arrows indicate coexpression.
Scale bar in (E) = 250 μM and applies to (A), (C), and (E). Scale bar in (F) = 25 μM and applies to (B), (D), and (F). Scale bar in (G) = 20 μM. Scale bar in (I) = 100 μM and applies to (H) and (I).