Satellite glial cells modulate cholinergic transmission between sympathetic neurons

Abstract

AbstractPostganglionic sympathetic neurons and satellite glial cells are the two major cell types of the peripheral sympathetic ganglia. Sympathetic neurons project to and provide neural control of peripheral organs and have been implicated in human disorders ranging from cardiovascular disease to peripheral neuropathies. Here we show that satellite glia regulate postnatal development and activity of sympathetic neurons, providing evidence for local ganglionic control of sympathetic drive. We show changes in the cellular architecture of the rat sympathetic ganglia during the postnatal period, with satellite glia enwrapping sympathetic neuronal somata during a period of neuronal hypertrophy. In culture, satellite glia contribute to neuronal survival, promote synapse formation and play a modulatory role in neuron-to-neuron cholinergic neurotransmission, consistent with the close contact seen within the ganglia. Cultured satellite glia make and release neurotrophins, which can partially rescue the neurons from nerve growth factor deprivation. Electrophysiological recordings and immunocytochemical analysis on cultured sympathetic neurons show that satellite glial cells influence synapse number and total neuronal activity with little effect on neuronal intrinsic excitability. Thus, satellite glia play an early and ongoing role within the postnatal sympathetic ganglia, expanding our understanding of the contributions of local and target-derived factors in the regulation of sympathetic neuron function.