Abstract
Satellite glial cells (SGCs) are non-neuronal support cells found in the peripheral sympathetic ganglia that communicate bidirectionally with peripheral sympathetic neurons whose activity sets normal physiological responses. SGCs have a role in regulating the number of synapses formed in sympathetic neurons, however, it remains unclear if this regulation is activity-dependent. Understanding how satellite glial cells contribute to the output of sympathetic neurons can provide insights into diseases that arise from sympathetic dysfunction. This study aims to further investigate if SGCs regulate the number of neuronal synapses in an activity-dependent process. I used an established culture system that allows for culturing isolated neurons in the presence or absence of SGCs and identified the number of synapses formed between a normotensive (WKY) and hypertensive (SHR) strain. An increase in synapse density from WKY neurons (WKY N) in the absence of glia to WKY neuron-glia co-culture (WKY NG) was observed, but the opposite was observed in the intrinsically more active SHR strain, suggesting that SHR SGCs may lower the number of synapses in response to signaling from neurons in a high activity state. To test this, I chronically manipulated glial activity with excitatory DREADDs. My results showed a decrease in the number of synapses formed in WKY neurons after chronic activity, however, the opposite was observed in SHR. These results suggest that SGCs may play a key role in homeostatic plasticity and disruptions to SGCs functions may contribute to the development of pathology.