Microglia regulate RVLM‐projecting PVN neuronal activity

Microglia, the primary resident immune cells in the CNS, communicate with neurons very dynamically. Our previous studies show that activated microglia are involved in neurogenic hypertension. In the present study, we are investigating the mechanism by which microglia regulate RVLM‐projecting PVN neuronal activity in resting state. Adult male transgenic CD11b‐DTR mice were randomly assigned into two groups: sham control and diphtheria toxin (DT) groups, which received ICV infusion of saline or DT (depletion of microglia) respectively. Sympathetic neurons in the hypothalamic PVN are retrograde labeled by fluorescent microsphere from the brain stem RVLM. The electronic profile of RVLM‐PVN neurons are recorded in voltage clamp mode. Our results indicate that depletion of naïve microglia did not alter resting membrane potential nor membrane resistance. However, loss of microglia significantly inhibited outward potassium currents in RVLM‐PVN neurons. The frequency of mEPSP were also decreased in the PVN neurons in the absence of microglia. By confocal microscopy analysis, we found that there was a significantly decrease of spine density in the PVN neurons without microglia compared to the ones from the sham controls. Our results suggest that microglia directly regulate both intrinsic and extrinsic activities of the PVN sympathetic neurons. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .