Angiotensin II Infusion Results in Both Hypertension and Increased AMPA GluA1 Signaling in Hypothalamic Paraventricular Nucleus of Male but not Female Mice

The hypothalamic paraventricular nucleus (PVN) plays a key role in hypertension, however the signaling pathways that contribute to the adaptability of the PVN during hypertension are uncertain. We present evidence that signaling at the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) GluA1 receptor contributes to increased blood pressure in a model of neurogenic hypertension induced by 14-day slow-pressor angiotensin II (AngII) infusion in male mice. It was found that AngII hypertension was associated with an increase in plasma membrane affiliation of GluA1, but decreased GluA2, in dendritic profiles of PVN neurons expressing the TNFα type 1 receptor, a modulator of AMPA receptor trafficking. The increased plasma membrane GluA1 was paralleled by heightened AMPA currents in PVN-spinal cord projection neurons from AngII-infused male mice. Significantly, elevated AMPA currents in AngII-treated mice were blocked by 1-Naphthyl acetyl spermine trihydrochloride, pointing to the involvement of GluA2-lacking GluA1 receptors in the heightened AMPA signaling in PVN neurons. A further functional role for GluA1 in the PVN was demonstrated by the attenuated hypertensive response following silencing of GluA1 in the PVN of AngII-infused male mice. In female mice, AngII-infusion did not impact blood pressure or plasma membrane localization of GluA1 . Post-translational modifications that increase the plasma membrane localization of AMPA GluA1 and heighten the rapid excitatory signaling actions of glutamate in PVN neurons may serve as a molecular substrate underlying sex differences in hypertension.