Chloride homeostasis dysfunction drives hyperactivation of corticotropin-releasing factor-expressing neurons in the amygdala in stress-induced hypertension
Hongyu Ma, Ying Zhang, Xinqi Guo, Qiyue Zhao, Peiyun Yang, Yan Liu, Yue Guan, Yan Wei, Huijie Ma
Hongyu Ma, Ying Zhang, Xinqi Guo, Qiyue Zhao, Peiyun Yang, Yan Liu, Yue Guan, Yan Wei, Huijie Ma
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Research Article Cell biology Neuroscience

Chloride homeostasis dysfunction drives hyperactivation of corticotropin-releasing factor-expressing neurons in the amygdala in stress-induced hypertension

Abstract

Stress promotes the progression from borderline hypertension to sustained hypertension, but the mechanism remains unclear. We investigated the role of corticotropin-releasing factor (CRF)-expressing neurons in the central nucleus of amygdala (CeA) on arterial blood pressure (ABP) and sympathetic activity of borderline hypertensive rats (BHRs) subjected to chronic unpredictable mild stress (CUMS). CUMS induced sustained hypertension, and led to increased delta-FosB expression as well as enhanced spontaneous and evoked firing of CeA CRF-expressing neurons in BHRs. Furthermore, optogenetic activation of CeA CRF-expressing neurons significantly increased the sympathetic outflow and ABP in BHRs. Impaired GABAergic inhibition, a depolarizing shift of GABA reversal potential (EGABA), disrupted chloride homeostasis and increased NKCC1 expression were observed in CeA CRF-expressing neurons in BHRs subjected to CUMS. NKCC1 inhibition with bumetanide restored GABAergic inhibition and chloride homeostasis, normalized neuronal excitability, leading to reduced sympathetic vasomotor tone in CUMS BHRs. These results indicate that NKCC1-mediated disruption of chloride homeostasis in CeA CRF-expressing neurons contributes to elevated sympathetic activity and hypertension under chronic stress. These findings enhance our understanding of the neuronal and molecular mechanisms underlying stress-induced hypertension and reveal potential targets for its prevention and treatment.

Authors

Hongyu Ma, Ying Zhang, Xinqi Guo, Qiyue Zhao, Peiyun Yang, Yan Liu, Yue Guan, Yan Wei, Huijie Ma

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Figure 3

Optogenetic activation of CeA CRF-expressing neurons increases the sympathetic outflow and ABP in BHRs.

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Optogenetic activation of CeA CRF-expressing neurons increases the sympa...
(A) Experimental flow diagram shows the optogenetic viral vector injection to the CeA of rats and subsequent in vitro patch clamp recording and in vivo ABP and RSNA recording. (B) Schematic diagram shows the constructs of AAV vectors (a), injection of AAV vectors and implantation of optical fiber (b), and ChR2-eYFP expression within the CeA (c). (C) CeA CRF-expressing neurons were activated by blue illumination (473 nm, energy 5 mW, duration 7 seconds and delay 3 seconds in 10 seconds, total 60 seconds). The green arrow indicates an eYFP-labeled neuron with an attached recording electrode, and the blue arrow indicates an unlabeled control neuron. (D and E) Original traces (D) and summary data (E) show the effect of blue light illumination on the spontaneous firing activity of both eYFP labeled and unlabeled neurons in the CeA of BHRs (n = 6 neurons in each group). Two-tailed Student’s t-test. (F) Original recording traces show the effects of blue light stimulation of CeA CRF-expressing neurons at different frequencies (10 Hz, 20 Hz, 40 Hz) on ABP, HR, RSNA, and Int. RSNA of BHRs. (G–I) Summary data show changes of MAP (G), HR (H), Int. RSNA (I) in response to optostimulation of CeA CRF-expressing neurons in BHRs (n = 6 rats in each group). One-way ANOVA with Tukey’s multiple comparison tests. CeA, central nucleus of amygdala. Data are expressed as means ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001.