Neuroanatomical analysis of neuronal sets that co-express the growth hormone secretagogue receptor and the cannabinoid receptor type 1 in the mouse brain

SAENZ, CAMILA; FERNÁNDEZ, GIMENA; BARRILE, FRANCO; DE FRANCESCO, PABLO NICOLÁS; PERELLO, MARIO

Buenos Aires

Congreso; XXXVII Reunión Anual SAN 2022; 2022

Sociedad Argentina de Investigación en Neurociencias (SAN)

The growth hormone secretagogue receptor (GHSR) is a G-protein coupled receptor (GPCR) expressed in the brain, that mediates the effects of ghrelin. GHSR acts via ligand-independent mechanisms, like constitutive activity and allosteric modulation of other GPCRs. The cannabinoid receptor type 1 (CB1) is also a GPCR highly expressed in the brain, and it is activated by cannabinoids. GHSR and CB1 expression have been observed within many of the same brain nuclei, suggesting that these may act on common neuronal sets to mediate those neurobiological effects. Here, we explored the extent of this putative GHSR and CB1 interaction in male mice brain. To map GHSRs distribution, we used complementary approaches: 1) binding with fluorescent-labelled ghrelin (Fr-ghrelin) in wild-type mice and 2) visualizing the fluorescence of GHSR-eGFP mice, in which GHSR promoter drives the expression eGFP. In both cases, the presence of CB1 was shown by immunofluorescence using a validated antibody against CB1. Using the Fr-ghrelin labelling strategy, we found that cells containing both GHSR and CB1 are mainly located in the amygdala and hippocampus. In brain sections of GHSR-eGFP mice, we found cells containing both GHSR and CB1 mainly located in the dorsomedial hypothalamic nucleus and hippocampus area. In contrast, the simultaneous presence of GHSR and CB1 was less extensive elsewhere in the brain. Thus, we started to elucidate some of the neuronal populations where GHSR and CB1 may directly act.