GHSR1a constitutive and ligand evoked activity inhibits GABAergic transmission in primary neuronal cultures

MARTÍNEZ DAMONTE V; E JAVIER LOPEZ SOTO; MUSTAFÁ ER; RODRÍGUEZ SS; PERELLO M; RAINGO J

Huerta Grande, Córdoba

Congreso; XXIX Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia; 2014

Sociedad Argentina de Investigación en Neurociencia

GHSR1a constitutive and ligand evoked activity inhibits GABAergic transmission in primary neuronal cultures Ghrelin receptor (GHSR1a) activity modulates neuronal circuits that control appetite. GHSR1a is a G protein coupled receptor that shows constitutive and ligand-evoked activation. Previously we found that presynaptic voltage gated calcium channels are inhibited by both GHSR1a activities. Since GHSR1a is scattered expressed in many brain areas, in order to evaluate its presynaptic impact we need to develop an experimental setting with a large number of neuron expressing the receptor. We have built a lentiviral system suitable for evaluating the effect of GHSR1a on synaptic activity in hypothalamic neurons. We designed lentiviral transference plasmids containing the sequence of GHSR1a or a mutant lacking constitutive activity (GHSR1aA204E) both tagged with YFP. We first corroborated their functionality by imaging, inmunocytochemistry and electrophysiology. Next we infected neuronalcultures and evaluated synaptic activity. We found that inhibitory postsynaptic currents (IPSCs) are smaller when GHSR1a was expressed in comparison with GHSR1aA204E. This effect is dependent on voltage-operated calcium channels since control and infected cultures response to 0,5M sucrose stimulation was identical. Also ghrelin application decreases IPSCs on these infected cultures. We can suggest then that both GHSR1a constitutive and ligand evoked activity inhibit GABAergic transmission