scholarly journals Effects of bilateral lesions in the central amygdala on spontaneous baroreceptor reflex in conscious rats

2019 ◽  
Vol 8 (1) ◽  
pp. 45-50
Author(s):  
Kei Tsukioka ◽  
Ko Yamanaka ◽  
Hidefumi Waki
Keyword(s):  
Baroreceptor Reflex ◽  
Central Amygdala ◽  
Conscious Rats ◽  
Bilateral Lesions

Locus ceruleus modulates migrating myoelectric complex in rats

1992 ◽  
Vol 262 (6) ◽  
pp. G1121-G1126 ◽  
Author(s):  
B. Bonaz ◽  
L. Martin ◽  
E. Beurriand ◽  
M. Manier ◽  
J. Hostein ◽  
...  
Keyword(s):  
Locus Ceruleus ◽  
Intracerebroventricular Injection ◽  
Conscious Rats ◽  
Migrating Myoelectric Complex ◽  
Cell Groups ◽  
Partial Lesion ◽  
Central Tegmental Tract ◽  
6 Hydroxydopamine ◽  
Bilateral Lesions

The role of the locus ceruleus (LC) in the control of migrating myoelectric complex (MMC) was investigated in rats with lesions induced by injections of 6-hydroxydopamine (6-OHDA). Control animals received the vehicle alone. MMC was recorded in conscious rats chronically fitted with electrodes. After 6-OHDA was injected into the LC, lesions of the LC were total, partial (mostly rostral), or ineffective. The MMC period was significantly longer in animals with a total or partial lesion but was unchanged in animals with an ineffective lesion. No lesion of other brain noradrenergic nuclei was observed. The longer MMC period is comparable to that obtained after intracerebroventricular injection of 6-OHDA, which is responsible for a more diffuse destruction of brain noradrenergic systems, including LC itself. Bilateral lesions of the central tegmental tract, which carries ascending noradrenergic axons from the medullary and pontine cell groups outside the LC, do not alter the MMC cycle. Consequently, the LC is most likely the major brain noradrenergic candidate for modulating the MMC pattern in rats.

Role of nitric oxide in regulation of renal sympathetic nerve activity during hemorrhage in conscious rats

1999 ◽  
Vol 277 (1) ◽  
pp. H8-H14 ◽  
Author(s):  
Yoshihide Fujisawa ◽  
Naoko Mori ◽  
Kouichi Yube ◽  
Hiroshi Miyanaka ◽  
Akira Miyatake ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Saline Group ◽  
Baroreceptor Reflex ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Conscious Rats ◽  
Renal Sympathetic Nerve ◽  
Renal Sympathetic

The effect of inhibition of nitric oxide (NO) synthesis on the responses of blood pressure (BP), heart rate (HR), and renal sympathetic nerve activity (RSNA) during hemorrhaging was examined with the use of an NO synthase inhibitor, NG-nitro-l-arginine methyl ester (l-NAME), in conscious rats. In the 0.9% saline group, hemorrhage (10 ml/kg body wt) did not alter BP but significantly increased HR and RSNA by 88 ± 12 beats/min and 67 ± 12%, respectively. Intravenous infusion of l-NAME (50 μg ⋅ kg−1⋅ min−1) significantly attenuated these tachycardic and sympathoexcitatory responses to hemorrhage (14 ± 7 beats/min and 26 ± 12%, respectively). Pretreatment ofl-arginine (87 mg/kg) recovered the attenuation of HR and RSNA responses induced byl-NAME (92 ± 6 beats/min and 64 ± 10%, respectively).l-NAME by itself did not alter the baroreceptor reflex control of HR and RSNA. Hemorrhage increased the plasma vasopressin concentration, and its increment in thel-NAME-treated group was significantly higher than that in the 0.9% saline group. Pretreatment with the vascular arginine vasopressin V1-receptor antagonist OPC-21268 (5 mg/kg) recovered the attenuation of RSNA response induced byl-NAME (54 ± 7%). These results indicate that NO modulated HR and RSNA responses to hemorrhage but did not directly affect the baroreceptor reflex arch. It can be assumed that NO modulated the baroreflex function by altering the secretion of vasopressin induced by hemorrhage.

Chronic nucleus tractus solitarius lesions do not prevent hypovolemia-induced vasopressin secretion in rats

1994 ◽  
Vol 267 (4) ◽  
pp. R965-R973 ◽  
Author(s):  
A. M. Schreihofer ◽  
E. M. Stricker ◽  
A. F. Sved
Keyword(s):  
Polyethylene Glycol ◽  
Plasma Volume ◽  
Nucleus Tractus Solitarius ◽  
Baroreceptor Reflex ◽  
Bilateral Vagotomy ◽  
Vasopressin Secretion ◽  
Bilateral Lesions ◽  
Alpha Chloralose ◽  
And Control ◽  
Arterial Baroreceptor

The present study examined the hypothesis that hypovolemia stimulates vasopressin (VP) secretion by removing tonic inhibitory baroreceptor input. Serial hemorrhage (4 samples of 2 ml/300 g body wt taken every 10 min) increased plasma VP levels in conscious rats devoid of cardiac and arterial baroreceptor reflex responses due to chronic bilateral lesions of nucleus tractus solitarius (NTS). The VP response to hemorrhage was similar to that seen in control rats and chronic sinoaortic-denervated (SAD) rats. After subcutaneous injection of 30% polyethylene glycol, NTS-lesioned rats, SAD rats, and control rats had elevated VP levels that correlated with the induced depletion of plasma volume. Additionally, in alpha-chloralose-anesthetized control rats, chronic SAD rats, and chronic NTS-lesioned rats, bilateral vagotomy had minimal effects on basal VP levels, and vagotomy in chronic NTS-lesioned rats did not prevent hemorrhage-evoked increases in VP secretion. These results do not support the idea that hemorrhage-induced VP secretion occurs through reduction in tonic inhibitory baroreceptor input. Instead, neither cardiac nor arterial baroreceptor input appears to be necessary for hypovolemia-induced VP secretion in rats.

scholarly journals Renal denervation normalizes pressure and baroreceptor reflex in high renin hypertension in conscious rats.

Hypertension ◽  
1992 ◽  
Vol 19 (2_Suppl) ◽  
pp. II17-II17 ◽  
Author(s):  
V. L. Oliveira ◽  
M. C. Irigoyen ◽  
E. D. Moreira ◽  
C. Strunz ◽  
E. M. Krieger
Keyword(s):  
Renal Denervation ◽  
Baroreceptor Reflex ◽  
Conscious Rats

Commissural NTS contributes to pressor responses to glutamate injected into the medial NTS of awake rats

1996 ◽  
Vol 270 (6) ◽  
pp. R1220-R1225 ◽  
Author(s):  
E. Colombari ◽  
J. V. Menani ◽  
W. T. Talman
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Baroreceptor Reflex ◽  
Electrolytic Lesion ◽  
Conscious Rats ◽  
Reflex Pathways ◽  
Pressor Responses ◽  
Reflex Activation ◽  
Change In Mean ◽  
Awake Rats

In the present study we investigated whether interruption of the chemoreceptor reflex by an electrolytic lesion of the commissural subnucleus of the nucleus tractus solitarii (commNTS) influenced pressor and bradycardic responses induced by microinjection of L-glutamate (L-Glu) into the medial NTS (mNTS) of conscious rats. Seven days after sham lesions, seven rats demonstrated significant pressor [change in mean arterial pressure (MAP) = +33 +/- 3 mmHg] and bradycardic [change in heart rate (HR) = -74 +/- 8 beats/min (bpm)] responses to chemoreceptor reflex activation by intravenous injection of KCN. Likewise, L-Glu (1 nmol in 100 nl) injected into the mNTS in sham rats induced pressor (+29 +/- 2 mmHg) and bradycardic responses (-90 +/- 8 bpm). However, in 11 rats with lesions in commNTS, pressor and bradycardic chemoreceptor reflex responses were abolished, and injection of L-Glu into the mNTS decreased MAP (-14 +/- 6 mmHg) and HR (-59 +/- 16 bpm) as is reported in anesthetized control rats. We conclude that pressor responses induced by L-Glu microinjected into the baroreceptor reflex region of mNTS in conscious rats depend on the integrity of the commNTS, which plays an important role in central chemoreceptor reflex pathways.

Effects of chronic lesions of the anteroventral third ventricle region on baroreceptor reflex function in conscious rats

1999 ◽  
Vol 835 (2) ◽  
pp. 330-333 ◽  
Author(s):  
Stephen J. Lewis ◽  
Erin J. Whalen ◽  
Terry G. Beltz ◽  
Alan Kim Johnson
Keyword(s):  
Third Ventricle ◽  
Baroreceptor Reflex ◽  
Conscious Rats

scholarly journals Overexpression of oxytocin receptors in the hypothalamic PVN increases baroreceptor reflex sensitivity and buffers BP variability in conscious rats

2014 ◽  
Vol 171 (19) ◽  
pp. 4385-4398 ◽  
Author(s):  
Maja Lozić ◽  
Michael Greenwood ◽  
Olivera Šarenac ◽  
Andrew Martin ◽  
Charles Hindmarch ◽  
...  
Keyword(s):  
Baroreceptor Reflex ◽  
Conscious Rats ◽  
Oxytocin Receptors ◽  
Baroreceptor Reflex Sensitivity
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