NEW MUTANT OF MOUSE GHRELIN RECEPTOR (GHSR1aA203E) AS A TOOL TO STUDY THE RELEVANCE OF GHSR1A CONSTITUTIVE ACTIVITY IN NEURONS

CONSTANZA CRISTALDI, ROMÁN EMILIO MUSTAFÁ,VALENTINA MARTÍNEZ DAMONTE, MARIO PERELLÓ, SILVIA SUSANA RODRÍGUEZ, JESICA RAINGO; JEFF ZIGMAN

Buenos Aires

Congreso; Reunión conjunta de sociedades de biociencia; 2017

The ghrelin receptor (GHSR1a) is a G protein coupled receptor expressed in the brain that controls fundamental functions such as food intake and energy balance (Hypothalamus), mood behavior (limbic system) and memory and learning (hippocampus). Recently we found that this receptor is capable of controlling presynaptic voltage gated calcium channels (VGCC). Interestingly, GHSR1a has the singularity of having high level of activity in absence of its agonist, the hormone ghrelin. We hypothesized that GHSR1a constitutive activity is relevant in brain areas with limited access to ghrelin, a hormone produce by stomach cells. In order to test this hypothesis in mouse neurons we developed an experimental tool: the murine version of a natural human GHSR1a mutant that lacks constitutive activity (GHSR1aA204E). We mutated the analog alanine in the mouse sequence of GHSR1a (GHSR1aA203E) and we tested it by patch clamp and imaging experiments where we found that this mouse GHSR1a mutant behaves identically to the human version. Our experiments measuring VGCC currents in HEK cells transfected with the VGCC subunits and the receptor demonstrated the lack of effect of GHSR1aA203E on basal calcium currents, utilizing the wild type mouse GHSR1a as a positive control of basal current inhibition (p