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

MARTINEZ DAMONTE V; RODRÍGUEZ SS; MUSTAFÁ ER; ZIGMAN J; CRISTALDI C; PERELLO M; RAINGO J

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

The ghrelin receptor (GHSR1a) is a G protein coupled receptorexpressed in the brain that controls fundamental functions such asfood intake and energy balance (Hypothalamus), mood behavior(limbic system) and memory and learning (hippocampus). Recentlywe found that this receptor is capable of controlling presynaptic voltagegated calcium channels (VGCC). Interestingly, GHSR1a hasthe singularity of having high level of activity in absence of its agonist,the hormone ghrelin. We hypothesized that GHSR1a constitutiveactivity is relevant in brain areas with limited access to ghrelin, ahormone produce by stomach cells. In order to test this hypothesisin mouse neurons we developed an experimental tool: the murineversion of a natural human GHSR1a mutant that lacks constitutiveactivity (GHSR1aA204E). We mutated the analog alanine in themouse sequence of GHSR1a (GHSR1aA203E) and we tested itby patch clamp and imaging experiments where we found that thismouse GHSR1a mutant behaves identically to the human version.Our experiments measuring VGCC currents in HEK cells transfectedwith the VGCC subunits and the receptor demonstrated the lackof effect of GHSR1aA203E on basal calcium currents, utilizing thewild type mouse GHSR1a as a positive control of basal current inhibition(p