A Novel Postsynaptic Group II Metabotropic Glutamate Receptor Role in Modulating Baroreceptor Signal Transmission

• DOI: 10.1523/jneurosci.2617-09.2009
• Publication Date: 2009-09-23T17:30:28Z
• Authors: Shin-ichi Sekizawa; Andrea G. Bechtold; Rick C. Tham; Ann C. Bonham
• Keywords: CNQX

The nucleus tractus solitarius (NTS) is essential for orchestrating baroreflex control of blood pressure. When a change in pressure occurs, the information transmitted by baroreceptor afferent fibers to central network glutamate binding ionotropic receptors on second-order neurons. Glutamate also activates presynaptic group II and III metabotropic (mGluRs), depressing both GABA release modulate signal transmission. Here we present novel role postsynaptic mGluRs further fine-tune transmission at first synapses. In brainstem slice with blocked, whole-cell patch-clamp recordings neurons revealed that two mGluR agonists evoked concentration-dependent membrane hyperpolarizations. hyperpolarization remained when contribution was prevented Cd(2+), blocked intervention intracellular dialysis G-protein signaling inhibitor, mimicked endogenous stimulation, antagonist. Postsynaptic localization confirmed fluorescent confocal immunohistochemistry light microscopy. Group induced-currents consisted voltage-dependent outward inward components, tetraethylammonium chloride tetrodotoxin, respectively. contrast mGluR-induced hyperpolarization, there no effect intrinsic excitability as determined action potential shape or firing response depolarizing current injections. data suggest mechanism NTS.