Astrocytic-neuronal interaction on the excitatory transmission in the nucleus tractus solitarius (NTS) of mices

• Grant number: 18/02336-0
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2019
• End date: February 28, 2022
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Benedito Honorio Machado
• Grantee: Benedito Honorio Machado
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Daniela Accorsi Mendonça Eichenberger

Abstract

Synapses are the main functional element of the CNS and it has been recently described that some synapses present pre- and post-synaptic neurons involved by astrocytes, which are named tripartite synapse. There is an intense communication between astrocyte-neuron in tripartite synapse, which modulates the synaptic activity. Astrocytes express glutamate transporters that up take glutamate from the synaptic cleft, decreasing the glutamate available to bind to the postsynaptic receptors. In synapses where astrocytes are not involving neurons, glutamate can diffuse out of the synaptic cleft and bind to extra-synaptic receptors, such as extra-synaptic NMDA receptors (rNMDAe). In neurons the stimulation of rNMDAe produces a tonic current (INMDA tonic) caused by the flow of Ca2+ through the membrane. An increase in intracellular Ca2+ concentration may promote the insertion of new AMPA subtype receptors into the membrane and increase glutamatergic transmission. NTS is a region of the brainstem responsible for the synaptic processing of neuronal pathways involved with cardiovascular and respiratory reflexes. It has reported that NTS has both tripartite synapses and synapses without astrocytes. The main goals of this project are the following: (1) to evaluate whether NTS synapses of mice present INMDA tonic and (2) whether this current can facilitate the glutamatergic transmission through interaction with AMPA receptors. For this, the synaptic activity will be recorded using the patch-clamp technique. (AU)