Altered NMDA receptor‐evoked intracellular Ca2+ dynamics in magnocellular neurosecretory neurons of hypertensive rats

摘要

Key points class="unordered" style="list-style-type:disc" id="tjp12674-list-0001">NMDA receptor (NMDAR)‐mediated Ca²⁺ signalling plays a critical role in modulating hypothalamic neurosecretory function. However, whether an altered NMDAR‐evoked changes in Ca²⁺ (NMDAR‐ΔCa²⁺) signalling in magnocellular neurosecretory cells (MNCs) may contribute to neurohumoral activation during disease states is unknown.We show that activation of NMDARs evoked similar inward currents in MNCs of sham and renovascular hypertensive (RVH) rats. Despite this, a prolonged and larger NMDAR‐ΔCa²⁺ response was observed in the latter.The exacerbated NMDAR‐ΔCa²⁺ responses in MNCs of RVH rats affected both somatic and dendritic compartments.Inhibition of the endoplasmic reticulum sarcoendoplasmic reticulum calcium trasport ATPase (SERCA) pump prolonged NMDAR‐ΔCa²⁺ responses in sham rats, but not in RVH rats.Our study supports an altered spatiotemporal dynamic of NMDAR‐ΔCa²⁺ signalling in MNCs from RVH rats, partly due to blunted endoplasmic reticulum Ca²⁺ buffering capacity.