The co-expression of POMC, NPY and 5-HTRs in the ARC

Have you ever been wondering about what the are the co-expression patterns of pro-opiomelanocortin (POMC) and the neuropeptide Y (NPY) neurons in the arcuate nucleus of the hypothalamus (ARC) with what serotonin receptors (5-HTRs)? Yes, I thought so... Here is little info for you!

I have included the methods used to label the peptide (to label a protein: immunireactivity = IR; to label protein's mRNA: in situ hybridisation = ISH) and the animal model with the validation of the model where relevant.

POMC & 5-HT2CRs

wt RAT
50% to 80% of POMC cells (POMC-IR) (from rostral to caudal ARC respectively) express 2Cs (2C-ISH) in a wt rat (Heisler et al. 2002)

POMC-tau/lacZ+/- MOUSE
75% of POMC cells (beta-galactosidase-IR) express 5-HT2CRs (5-HT2CR-IR - but uses a dodgy antibody) in a POMC-tau/lacZ+/- (Lam et al., 2008)
28% of 5-HT2CR cells (5-HT2CR-IR - but uses a dodgy antibody) express POMCs (beta-galactosidase-IR) in a POMC-tau/lacZ+/- (Lam et al. 2008)
validation:
100% of beta-galactosidase-IR express POMC-ISH in a POMC-tau/lacZ+/- (Lam et al., 2008)

NPY & 5-HT1BRs

NPY-GFP MOUSE
16.5% (1/6) of NPY cells (GFP-IR) express 5-HT1BRs (5-HT1BR-ISH) in a NPY-GFP mouse (Heisler et al., 2006)
33% (1/3) of 5-HT1BR cells (5-HT1BR-ISH) express NPY (GFP-IR) in a NPY-GFP mouse (Heisler et al., 2006)
validation:
99.5% of GFP-IR express AgRP-ISH in a NPY-GFP mouse (Heisler et al., 2006)

Of note, apparently there are differences in expression of POMC in mice and in rats (Cowley et al., 2001) so that might explain the differences (in addition to the different genetic model).