Oral Presentation The International Congress of Neuroendocrinology 2014

Conventional and unconventional inter-neuronal communication modalities after physiological stressors (#102)

Javier E Stern 1
  1. Georgia Regents University, Augusta, GA, United States

Communication between pairs of neurons in the central nervous system typically involves classical “hard-wired” synaptic transmission, characterized by high temporal and spatial precision.  Over the last two decades however, the repertoire of communication modalities in the brain has expanded, to include less-conventional forms characterized by a more diffuse, and less temporally precise transfer of information. These forms are best suited to mediate communication among entire neuronal populations, recognized now to be a fundamental process in the generation of complex behaviors. In response to an osmotic stressor, the hypothalamic paraventricular nucleus (PVN) generates a multimodal homeostatic response that involves an orchestrated neuroendocrine (systemic release of vasopressin) and autonomic (sympathetic outflow to the kidneys) components.  The precise mechanisms that underlie inter-population crosstalk between these two distinct neuronal populations during an osmotic stressor, however, remain largely unknown. We identified a novel inter-population signaling modality that involves dendritic release of neuropeptides. We found that activity-dependent dendritic release of vasopressin from neurosecretory neurons in the PVN acted in a diffusible manner to increase the activity of distant (~100 µm) presympathetic neurons, resulting in turn in an integrated sympathoexcitatory population response (Son et al., Neuron 2013). This crosstalk was engaged by an NMDA-mediated increase in dendritic Ca2+, was influenced by vasopressin’s ability to diffuse in the extracellular space, and involved Ca2+-dependent activation of TRPM4/5 channels at the target neurons. Finally, using an in vivo hyperosmotic challenge, we provide direct evidence supporting a critical role for this inter-population crosstalk in the generation of a proper systemic sympathoexcitatory homeostatic response to a hyper osmotic challenge.    

  1. Son SJ, Filosa FA, Potapenko ES, Biancardi VC, Zheng H, Patel KP, Tobin VA, Ludwig M, Stern JE. Dendritic peptide release mediates interpopulation crosstalk between neurosecretory and pre autonomic networks. Neuron 78 (6) 1026-49, 2013.