Involvement of Neuropeptide Y within Paraventricular Nucleus in Electroacupuncture Inhibiting Sympathetic Activities in Hypertensive Rats

Abstract

Although electroacupuncture (EA) has been used to decrease the blood pressure (BP) clinically, the underlying mechanisms are not clearly clarified. This study aimed to assess the hypothesis that EA treatment exerts a hypotensive action via suppressing sympathetic activities and modulating neuropeptide Y (NPY) function within the paraventricular nucleus (PVN) of hypertensive rats. Male Sprague-Dawley rats were selected for the experiment, and the hypertensive models were established by the two-kidney, one-clip (2K1C) method. Then, the rats were randomly assigned to the sham group, 2K1C group, 2K1C plus EA group, and 2K1C plus sham EA group. EA treatment at the acupoints ST36 and ST40 overlying the peroneal nerves was given once a day for 30 days. The radiotelemetry system was applied to collect the arterial BP recordings. Power spectral analyses of BP variability, BP responses to ganglionic blockade, and plasma levels of norepinephrine and epinephrine were performed to assess the changes in sympathetic nerve activity. Real-time PCR and Western blots were carried out to examine the expression of NPY system in the PVN. The responses of PVN microinjection with NPY Y1R antagonist BIBO3304 were detected to check the endogenous NPY tone. The results showed that the enhanced arterial BP and sympathetic activities were effectively reduced by 30 days of EA treatment, and baroreflex sensitivity was improved in 2K1C hypertensive rats. The level of NPY mRNA and protein expression in the PVN was markedly upregulated by EA treatment in 2K1C rats. In addition, the pressor responses of PVN microinjection with NPY Y1R antagonist BIBO3304 in 2K1C models were remarkably augmented by the EA stimulation. Our results indicate that the increased NPY expression and function in the PVN induced by EA treatment contribute to antihypertensive and sympathetic suppression on hypertensive rats. The findings may elucidate the underlying mechanisms of the acupuncture to be a potential therapeutic strategy against hypertension.

Electroacupuncture Treats Myocardial Infarction by Influencing the Regulation of Substance P in the Neurovascular to Modulate PGI2/TXA2 Metabolic Homeostasis via PI3K/AKT Pathway: A Bioinformatics-Based Multiomics and Experimental Study

“…Studies have also demonstrated that EA increases the expression of NPY in the hypothalamus and attenuates the stress response under chronic stress conditions [ 20 , 21 ]. Further, EA also induces NPY expression in the paraventricular nucleus and inhibits antihypertensive and sympathetic activities [ 22 ]. EA exerts its protective effect by activating sympathetic alpha-adrenergic receptors in myocardial ischemic injury [ 23 , 24 ].…”

Trigeminal electrical stimulation with ULFTENS of the dorsal anterior mucosal surface of the tongue: Effects on Heart Rate Variability (HRV)

“…Dental ULFTENS, unlike other trigeminal transcutaneous electrical stimulation techniques, is delivered at a frequency of 0.66 hz (Ultra Low), also called Acupuncture-like. Part of its central effects on cardiovascular activity on the PAG-RVLM circuit (Periaqueductal gray-Rostroventrolater medulla circuit) [ 51 , 52 ] and the vagal baroreflex circuit of the nucleus tractus solitarius [ 53 ] could be related to this mode of delivery. On the other hand, collaterals are sent from the PAG-RVLM circuit both to the locus coeruleus and to the caudal part of the nucleus of the solitary tract [ 54 ], largely justifying the functional relationships activated by ULFTENS between PAG-RVLM- Nago-LC nuclei.…”

Research Progress of Acupuncture Analgesia Based on Autonomic Nerve Regulation Pathway

“…Acupuncture can regulate inflammatory diseases, gastrointestinal functional diseases through the ANS as well as cardiovascular, lung, kidney, pancreatic, and other visceral functional diseases. For example, ST36 and ST40 electroacupuncture inhibit sympathetic nerve activity in hypertensive rats, regulate Neuropeptide Y (NPY) expression in the PVN, and reduce blood pressure [65] . Electroacupuncture Jianshi (PC5) and PC6 can inhibit increase in blood pressure by regulating cardiovascular sympathetic neurons in the hypothalamic arcuate nucleus and ventrolateral periaqueductal gray (vlPAG) [66][67] .…”

“…Gastric motility [62] RN12, BL21 Parasympathetic Regulation of gastric motility via the PVN-DVC-vagus-gastric nerve pathway Gastric motility [63] PC6 Parasympathetic Reducing inhibition of efferent vagal motor fibers by inhibiting GABA transmission to the DMV, thereby promoting efferent vagal activity and increasing gastric motility Gastric motility [64] ST36 Parasympathetic The NR2A-containing NMDARs are essential for NMDAR-mediated enhancement of gastric motility caused by stimulating ST36 Hypertension [65] ST36, ST40 Sympathetic Inducing increases in NPY expression and function in the PVN contribute to hypotension and sympathetic inhibition in hypertensive rats Hypertension [66][67] PC5, PC6 Sympathetic/ Parasympathetic Improving autonomic balance, increasing sympathetic and reducing parasympathetic tone; suppresses blood pressure elevation by activating the arcuate nucleus, ventrolateral periaqueductal gray and inhibiting cardiovascular sympathetic neurons in the ventrolateral medulla Acute respiratory distress syndrome [68] ST36…”