Growth Hormone Secretagogue Receptor type 1a (GHSR1a) constitutive activity impairs voltage-gated calcium channels (CaV)- dependent inhibitory neurotransmission in hippocampal neurons

RODRÍGUEZ, S. S.; RAINGO, J.; MARTINEZ DAMONTE, V.

Congreso; 2nd Federation of Neuroscience Societies in Latin America and the Caribbean (FALAN) Congress; 2016

GHSR1a is a Gprotein coupled receptor highly expressed in several regions of thecentral nervous system both pre and postsynaptically. In the hippocampus, ithas been descripted that ghrelin enhances excitatory neurotransmission.How it modulates neuronal activity is still poorly understood but multiplemechanisms seem to be implicated. GHSR1a displays both ghrelinevoked andconstitutive activity, which relies only on GHSR1a expression levels. Presynaptic CaV2 are essential for transducing action potentials into calcium influx to the presynaptic terminal which triggers neurotransmitter release. We have found that CaV2 are efficiently inhibited by GHSR1a constitutive and ghrelinevoked activity in the hippocampus. Thus, we propose that GHSR1a may be enriched in GABAergic neurons in the hippocampus in order to impair GABAergic but not glutamatergic transmission. Then, we evaluated CaVdependent neurotransmission recording excitatory and inhibitory post synaptic currents using different strategies to modulate GHSR1a expression levels in hippocampal cultured neurons and found an impairment in GABAergicneurotransmission but no differences in glutamatergic transmission. We alsostudied CaVindependent neurotransmission.