Hypothalamic paraventricular nucleus inhibition decreases renal sympathetic nerve activity in hypertensive and normotensive rats

2003 ◽  
Vol 108 (1-2) ◽  
pp. 17-21 ◽  
Author(s):  
Asa Akine ◽  
Marisa Montanaro ◽  
Andrew M. Allen
Keyword(s):  
Paraventricular Nucleus ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Hypothalamic Paraventricular Nucleus ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Renal Sympathetic Nerve ◽  
Renal Sympathetic

scholarly journals Enhanced angiotensin-mediated excitation of renal sympathetic nerve activity within the paraventricular nucleus of anesthetized rats with heart failure

2009 ◽  
Vol 297 (5) ◽  
pp. R1364-R1374 ◽  
Author(s):  
Hong Zheng ◽  
Yi-Fan Li ◽  
Wei Wang ◽  
Kaushik P. Patel
Keyword(s):  
Heart Failure ◽  
Paraventricular Nucleus ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Receptor Expression ◽  
Ang Ii ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Renal Sympathetic Nerve ◽  
Renal Sympathetic

Chronic heart failure (HF) is characterized by increased sympathetic drive. Enhanced angiotensin II (ANG II) activity may contribute to the increased sympathoexcitation under HF condition. The present study examined sympathoexcitation by 1) the effects of ANG II in the paraventricular nucleus (PVN) on renal sympathetic nerve activity (RSNA), and 2) the altered ANG II type 1 (AT1) receptor expression during HF. Left coronary artery ligation was used to induce HF. In the anesthetized Sprague-Dawley rats, microinjection of ANG II (0.05–1 nmol) into the PVN increased RSNA, mean arterial pressure (MAP), and heart rate (HR) in both sham-operated and HF rats. The responses of RSNA and HR were significantly enhanced in rats with HF compared with sham rats (RSNA: 64 ± 8% vs. 33 ± 4%, P < 0.05). Microinjection of AT1 receptor antagonist losartan into the PVN produced a decrease of RSNA, MAP, and HR in both sham and HF rats. The RSNA and HR responses to losartan in HF rats were significantly greater (RSNA: −25 ± 4% vs. −13 ± 1%, P < 0.05). Using RT-PCR and Western blot analysis, we found that there were significant increases in the AT1 receptor mRNA (Δ186 ± 39%) and protein levels (Δ88 ± 20%) in the PVN of rats with HF ( P < 0.05). The immunofluorescence of AT1 receptors was significantly higher in the PVN of rats with HF. These data support the conclusion that an increased angiotensinergic activity on sympathetic regulation, due to the upregulation of ANG II AT1 receptors within the PVN, may contribute to the elevated sympathoexcitation that is observed during HF.

Increase in sympathetic outflow by paraventricular nucleus stimulation in awake rats

1989 ◽  
Vol 256 (6) ◽  
pp. R1325-R1330 ◽  
Author(s):  
H. Kannan ◽  
Y. Hayashida ◽  
H. Yamashita
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Paraventricular Nucleus ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Sympathetic Outflow ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Renal Sympathetic Nerve ◽  
Renal Sympathetic

Our previous studies demonstrated that stimulation of the hypothalamic paraventricular nucleus (PVN) in anesthetized rats evoked a depressor response accompanied with a decrease in sympathetic outflow (H. Kannan, A. Niijima, and H. Yamashita, J. Auton. Nerv. Syst. 19: 83-86, 1987; H. Yamashita, H. Kannan, M. Kasai, and T. Osaka, J. Auton. Nerv. Syst. 19: 229-234, 1987). Because anesthesia may alter cardiovascular responses, we examined in conscious rats the effects of PVN stimulation on arterial pressure, heart rate, and renal sympathetic nerve activity. Electrical stimulation through chronically implanted electrodes evoked increases in arterial pressure and renal sympathetic nerve activity with a slight decrease in heart rate. The magnitude of responses was dependent on the frequency and the intensity of the stimulus. Latency of the excitatory response of the renal sympathetic nerve activity was approximately 70 ms. Microinjection of L-glutamate (0.5 M, 200 nl) into the PVN area also elicited increases in blood pressure and renal sympathetic nerve activity. These results suggest that activation of PVN neurons in conscious rats produces pressor responses due to an increase in the sympathetic outflow. These findings contrast with those obtained previously in anesthetized rats.

scholarly journals Role of the hypothalamic PVN in the regulation of renal sympathetic nerve activity and blood flow during hyperthermia and in heart failure

2010 ◽  
Vol 298 (4) ◽  
pp. F839-F846 ◽  
Author(s):  
Emilio Badoer
Keyword(s):  
Heart Failure ◽  
Blood Flow ◽  
Paraventricular Nucleus ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Renal Sympathetic Nerve ◽  
Renal Sympathetic

The hypothalamic paraventricular nucleus is a key integrative area in the brain involved in influencing sympathetic nerve activity and in the release of hormones or releasing factors that contribute to regulating body fluid homeostasis and endocrine function. The endocrine and hormonal regulatory function of the paraventricular nucleus is well studied, but the regulation of sympathetic nerve activity and blood flow by this region is less clear. Here we review the critical role of the paraventricular nucleus in regulating renal blood blow during hyperthermia and the evidence pointing to an important pathophysiological role of the paraventricular nucleus in the elevated renal sympathetic nerve activity that is a characteristic of heart failure.

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