Hemodynamic response to vasopressin during V1-receptor antagonism in baroreflex-deficient subjects

1995 ◽  
Vol 268 (1) ◽  
pp. R156-R163 ◽  
Author(s):  
K. M. Huch ◽  
K. R. Runyan ◽  
B. M. Wall ◽  
H. Gavras ◽  
C. R. Cooke
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Low Dose ◽  
Plasma Renin ◽  
High Dose ◽  
Receptor Blockade ◽  
Control Subjects ◽  
Vasodilatory Effect ◽  
Sympathetic Nervous ◽  
And Control

Six quadriplegic subjects and 6 control subjects received high-dose arginine vasopressin (AVP) infusions at rates of 500, 1,000, 2,000, and 4,000 microU.kg-1.min-1 in consecutive 10-min intervals. Six additional quadriplegic subjects received low-dose AVP infusions at rates of 50, 100, 200, 400, and 800 microU.kg-1.min-1. All subjects were studied once with and once without administration of a selective V1-receptor antagonist. During high-dose AVP infusions without V1-receptor blockade, mean arterial pressure (MAP) increased from 80 +/- 4 to 87 +/- 5 mmHg (P < 0.05) in quadriplegic subjects but was unchanged in control subjects. In the presence of V1-receptor blockade, MAP decreased from 75 +/- 4 to 58 +/- 4 mmHg (P < 0.001), and heart rate (HR) increased from 61 +/- 5 to 80 +/- 5 beats/min (P < 0.001) in quadriplegic subjects. In the studies on control subjects, MAP decreased only from 75 +/- 3 to 72 +/- 5 mmHg (P < 0.05), whereas HR increased from 64 +/- 4 to 87 +/- 4 beats/min (P < 0.001). Plasma renin activity (PRA) increased in both quadriplegic and control subjects. The effects of low-dose AVP infusions on MAP, HR, and PRA in quadriplegic subjects were similar to those observed during high-dose infusions. Thus, in the absence of baroreceptor-mediated sympathetic nervous system responses, a vasodilatory effect of AVP that is capable of producing marked reductions in MAP can be demonstrated in the presence of V1-receptor blockade.

scholarly journals Prenatal cold exposure causes hypertension in offspring by hyperactivity of the sympathetic nervous system

2019 ◽  
Vol 133 (9) ◽  
pp. 1097-1113 ◽  
Author(s):  
Ken Chen ◽  
Dongdong Sun ◽  
Shuang Qu ◽  
Yue Chen ◽  
Jialiang Wang ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Cold Exposure ◽  
Sodium Excretion ◽  
Adrenergic Receptor ◽  
At1 Receptor ◽  
Receptor Blockade ◽  
Sympathetic Nervous

Abstract Environmental temperature plays a role in the variation of blood pressure. Maternal cold stress could affect the physiological phenotype of the offspring, including blood pressure elevation. In the present study, we found that adult offspring of dams exposed to cold have increased systolic and diastolic blood pressure, and decreased urine volume and sodium excretion, accompanied by increased heart rate and heart rate variability, secondary to increased activity of the sympathetic nervous system. Renal denervation or adrenergic receptor blockade decreased blood pressure and increased sodium excretion. The increase in peripheral sympathetic nerve activity can be ascribed to the central nervous system because administration of clonidine, a centrally acting α2 adrenergic receptor agonist, lowered blood pressure to a greater degree in the prenatal cold-exposed than control offspring. Moreover, these prenatal cold-exposed offspring had hypothalamic paraventricular nucleus (PVN) disorder because magnetic resonance spectroscopy showed decreased N-acetylaspartate and increased choline and creatine ratios in the PVN. Additional studies found that prenatal cold exposure impaired the balance between inhibitory and excitatory neurons. This led to PVN overactivation that was related to enhanced PVN-angiotensin II type 1 (AT1) receptor expression and function. Microinjection of the AT1 receptor antagonist losartan in the PVN lowered blood pressure to a greater extent in prenatal cold-exposed that control offspring. The present study provides evidence for overactive peripheral and central sympathetic nervous systems in the pathogenesis of prenatal cold-induced hypertension. Central AT1 receptor blockade in the PVN may be a key step for treatment of this type hypertension.

Humoral Effects of the Oral Converting-Enzyme Inhibitor Sq 14 225 in Hypertensive Patients in Supine and Tilted Position

1979 ◽  
Vol 57 (s5) ◽  
pp. 149s-152s ◽  
Author(s):  
A. Morganti ◽  
T. G. Pickering ◽  
J. Lopez-Ovejero ◽  
J. H. Laragh
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Angiotensin Ii ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Renin Activity ◽  
Converting Enzyme ◽  
Hypertensive Patients ◽  
Sympathetic Nervous

1. To evaluate the effects of converting-enzyme inhibition on the sympathetic nervous system, on renin and on the other known regulators of aldosterone secretion, we measured blood pressure, heart rate, plasma noradrenaline, adrenaline, renin activity, aldosterone, cortisol and serum potassium in 15 sodium-repleted hypertensive patients in supine position and during 30 min of 65° head-up tilt before and during treatment with SQ 14 225. 2. SQ 14 225 produced significant decreases in supine blood pressure and plasma aldosterone and significant increments in plasma renin activity and potassium; in contrast, heart rate, noradrenaline, adrenaline and cortisol were unchanged. 3. While in control tilt studies blood pressure was always maintained, during treatment three of 15 patients had vasovagal syncopes. In the remaining 12 blood pressure was maintained during tilt on SQ 14 225; however, while the tilt-induced responses in heart rate and adrenaline were as in control studies, the 30 min increments in noradrenaline were significantly higher. 4. Both before and during treatment the responses of plasma renin activity and aldosterone to tilt were parallel, and correlated with each other, and cortisol and potassium changed only slightly. 5. It is concluded that the SQ 14 225-induced fall in blood pressure occurs without a concomitant rise in sympathetic nervous activity; thus the increase in supine plasma renin activity, being a reflection of the interruption of the angiotensin feedback mechanism on renin release, indicates an effective suppression of angiotensin II formation. 6. During SQ 14 225 the persistence of aldosterone response to tilt and its relationship with renin activity suggest that the enzymatic blockade is over-ridden; however, in the presence of a reduced formation of angiotensin II a more pronounced response of the sympathetic nervous system is required to defend blood pressure against postural changes.

scholarly journals Hemodynamic Patterns and Spectral Analysis of Heart Rate Variability during Dialysis Hypotension

1999 ◽  
Vol 10 (12) ◽  
pp. 2577-2584
Author(s):  
MICHEL G. W. BARNAS ◽  
WALTHER H. BOER ◽  
HEIN A. KOOMANS
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Spectral Analysis ◽  
Parasympathetic Nervous System ◽  
Intradialytic Hypotension ◽  
Intravascular Volume ◽  
Autonomic Nervous System Activity ◽  
System Activity ◽  
Nervous System Activity ◽  
Sympathetic Nervous

Abstract. Intradialytic hypotension, a major source of morbidity during hemodialysis and ultrafiltration, is often accompanied by paradoxical bradycardia. Relatively little is known about the sequential changes in autonomic nervous system activity up to and during the hypotensive episode. Continuous, beat-to-beat measurements of BP and heart rate were made during hemodialysis in patients prone (n = 8) and not prone (n = 11) to develop intradialytic hypotension. Off-line spectral analysis of heart rate variability (HRV) was performed to assess changes in autonomic nervous system activity during dialysis sessions both with and without hypotension. The low frequency (LF) component of HRV is thought to correlate with sympathetic nervous system activity, the high frequency (HF) component with that of the parasympathetic nervous system. In the sessions not complicated by symptomatic hypotension (n = 26), mean arterial BP (MAP) hardly fell, whereas heart rate increased from 77 ± 2 to 89 ± 5 bpm (P < 0.05). The LF component of HRV increased from 45.2 ± 5.0 normalized units (nu) to 59.9 ± 4.9 nu (P < 0.05), whereas the HF component fell from 54.8 ± 5.0 to 40.2 ± 4.4 nu (P < 0.05). These changes agree with compensatory baroreflex-mediated activation of the sympathetic nervous system (and suppressed parasympathetic activity) during ultrafiltration-induced intravascular volume depletion. In the sessions complicated by severe symptomatic hypotension (n = 22), the changes in heart rate and the results of spectral analysis of HRV were similar to those reported above up to the moment of sudden symptomatic (nausea, vomiting, dizziness, cramps) hypotension, whereas MAP had already fallen gradually from 94 ± 3 to 85 ± 3 mmHg (P < 0.05). The sudden further reduction in MAP (to 55 ± 2 mmHg, P < 0.02) was invariably accompanied by bradycardia (heart rate directly before hypotension 90 ± 2 bpm, during hypotension 69 ± 3 bpm, P < 0.002). The LF component of HRV fell from 62.8 ± 4.6 nu directly before to 40.0 ± 3.7 nu (P < 0.05) during hypotension, whereas the HF component increased from 37.9 ± 4.7 to 60.3 ± 3.7 nu (P < 0.05). These findings agree with activation of the cardiodepressor reflex, involving decreased sympathetic and increased parasympathetic nervous system activity, respectively. These findings indicate that activation of the sympatho-inhibitory cardiodepressor reflex (Bezold-Jarisch reflex), which is a physiologic response to a critical reduction in intravascular volume and cardiac filling, is the cause of sudden intradialytic hypotension.

Abstract P161: Tai Chi Movements Bring On Parasympathetic Nerve Output As Indicated By Audible Bowel Sounds

Circulation ◽  
2021 ◽  
Vol 143 (Suppl_1) ◽  
Author(s):  
Desuo Wang
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Tai Chi ◽  
Parasympathetic Nervous System ◽  
Autonomic Nerve ◽  
Parasympathetic Nerve ◽  
Bowel Sounds ◽  
Sympathetic Nervous ◽  
Tai Chi Exercise

Tai Chi movements are unique exercise that can improve cognition, strength somatomotor coordination, and enhance autonomic nerve regulation on internal organ function. The mild increase in heart rate and/or slight sweat during and after practicing Tai Chi indicates the activation of the sympathetic nervous system. There is lack of evidence to show that Tai Chi exercise enhances the activity of parasympathetic nervous system though it has been claimed that practicing Tai Chi could do so. The author tested the hypothesis that Tai Chi exercise brings on an increase in parasympathetic nerve outputs (PNO). The PNO is evaluated by recording the bowel sounds using an audio recorder (Sony digital voice recorder ICD-PX Series) and the data analyses were done using NCH software (WavePad audio editor). The heart rate was simultaneously recorded using a fingertip pulse oximeter (Zacurate Pro Series 500DL) during Tai Chi exercise. All the data was repeatedly collected from a Tai Chi Master in a study period of 6 months. A total of 30 recordings were used to carry out the analysis. The audible bowel sounds occurred when the performer started to do the Ready-Movement of Yang-style Tai Chi. These Tai Chi induced-bowel sounds lasted from the beginning to the end of a set of movements (3-5 min for 24-moves style). The frequency of bowel sounds was in a range of 0.2 to 3.5 Hz. The average number of bowel sounds was approximately 2.5 sounds per Tai Chi Move. The intensity and frequency of the bowel sounds are not related to the change of the performer’s heart rate. In comparison, meditation or deep squat exercise performed by the Tai Chi master did not cause any changes in the bowel sounds. According to the autonomic innervation of the GI tract, increase of bowel movements is mediated by PNO. In conclusion, Tai Chi movements can simultaneously exercise skeletal muscles, sympathetic nervous system and parasympathetic nervous system. The enhancement of parasympathetic nervous system output by Tai Chi exercise is a valuable modality of physical exercise for wellness.

scholarly journals Effect of Astragalus membranaceus Oral Solution on Lifespan and Learning and Memory Ability of Honey Bees

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Tao Hong ◽  
Long-Xue Li ◽  
Xiao-ping Han ◽  
Jing-liang Shi ◽  
Cai-yun Dan ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Honey Bees ◽  
Dose Group ◽  
Low Dose ◽  
Oral Solution ◽  
Astragalus Membranaceus ◽  
Control Group ◽  
High Dose ◽  
The Mean ◽  
And Control

In this study, the effects of Astragalus membranaceus oral solution on lifespan and learning and memory abilities of honey bees were evaluated. Two groups of bees were fed with sucrose syrup (50%) containing low dose (1.33%) and high dose (13.3%) of A. membranaceus oral solution, respectively. The proboscis extension response (PER) analysis was applied to examine the learning and memory capabilities of bees. Two genes related to memory formation in honey bees were determined by real-time PCR. High dose (13.3%) of A. membranaceus significantly decreased the mean lifespan of bees compared to the bees fed with low dose (1.33%) and control bees. No significant differences in lifespan of bees were found between low-dose-fed bees and control bees. The results of PER experiments showed apparent improvement in the memorizing ability of the high-dose group (in comparison with the control group). Moreover, the relative expression levels of Nmdar1 in the low-dose group and control group were significantly lower than those in the high-dose group. It is preliminarily concluded that A. membranaceus has an adverse effect on the mean lifespan of honey bees but might be helpful in strengthening memories.

scholarly journals Plasma Renin Activity and Sleep-Wake Structure of Narcoleptic Patients and Control Subjects Under Continuous Bedrest

SLEEP ◽  
1992 ◽  
Vol 15 (5) ◽  
pp. 423-429 ◽  
Author(s):  
H. Schulz ◽  
G. Brandenberger ◽  
S. Gudewill ◽  
D. Hasse ◽  
E. Kiss ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Renin Activity ◽  
Wake Structure ◽  
Control Subjects ◽  
And Control

Changes in the sympathetic nervous system induced by 42 days of head-down bed rest

1998 ◽  
Vol 274 (6) ◽  
pp. H1875-H1884 ◽  
Author(s):  
Dominique Sigaudo ◽  
Jacques-Olivier Fortrat ◽  
Anne-Marie Allevard ◽  
Alain Maillet ◽  
Jean-Marie Cottet-Emard ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Baroreflex Sensitivity ◽  
Bed Rest ◽  
Urinary Catecholamines ◽  
System Activity ◽  
Nervous System Activity ◽  
Sympathetic Nervous

Changes in autonomic nervous system activity could be linked to the orthostatic intolerance (OI) that individuals suffer after a spaceflight or head-down bed rest (HDBR). We examined this possibility by assessing the sympathetic nervous system activity during 42 days of HDBR in seven healthy men. Heart rate variability was studied with the use of power spectral analysis, which provided indicators of the sympathetic (SNSi) and parasympathetic (PNSi) nervous system influences on the heart. Urinary catecholamines and the spontaneous baroreflex sensitivity were measured. Urinary catecholamines decreased by 21.3%, showing a decrease in SNSi. Heart rate variability was greatly reduced during 42 days of HDBR with a drop in PNSi but with no significant changes in SNSi. The baroreflex sensitivity was greatly reduced (30.7%) on day 42 of HDBR. These results suggest a dissociation between the catecholamine response and the SNSi of the heart rate. This dissociation could be the consequence of an increase in β-adrenergic receptor density and/or activity induced by a decrease in catecholamines during HDBR. The subjects who suffered from OI also had a greater sympathetic response and much lower baroreflex sensitivity when supine than those who finished the stand test. However, the mean response of all subjects indicated that the sympathetic activity (catecholamine excretion) was probably slightly inhibited during HDBR and could contribute to OI.

Sedative and physiologic effects of tiletamine–zolazepam following buccal administration in cats

2019 ◽  
Vol 22 (2) ◽  
pp. 108-113 ◽  
Author(s):  
Pablo Nejamkin ◽  
Verónica Cavilla ◽  
María Clausse ◽  
Florencia Landivar ◽  
Augusto M Lorenzutti ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Low Dose ◽  
Sedation Score ◽  
High Dose ◽  
Physiological Effects ◽  
Chemical Restraint ◽  
Hemoglobin Saturation ◽  
Baseline Systolic Blood Pressure ◽  
Over Time

Objectives The aim of this study was to describe the sedative and some physiological effects of tiletamine–zolazepam following buccal administration (BA) in cats. Methods Seven healthy spayed European shorthair cats (three males, four females) were studied twice in this randomized, blinded, crossover study. Each cat received two doses of tiletamine–zolazepam by BA: the low-dose (LD) group consisted of 5 mg/kg of each drug, and the high-dose (HD) group consisted of 7.5 mg/kg of each. Baseline systolic blood pressure (SAP), heart rate (HR), respiratory rate (RR) and a sedation score were recorded prior to administration of each treatment. The same variables plus the percentage of hemoglobin saturated with oxygen as measured by pulse oximetry (SpO2) were recorded at predefined intervals for the next 2 h. Results All cats completed the study. No retching or vomiting were observed. Hypersalivation was observed in 0/7 and 3/7 for LD and HD groups, respectively ( P = 0.2). There were significant changes in scores over time for posture, response to clippers and response to manual restraint for both groups, without differences between groups. RR, HR and SAP changed significantly over time. SAP and RR were significantly lower for the HD than for the LD group. No values for hemoglobin saturation <95% were observed. Conclusions and relevance BA of tiletamine–zolazepam at the doses studied here is a simple and effective method for chemical restraint in cats, where the LD group had a lower impact on SAP and RR than the HD group.

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