Transfer function analysis of ventilatory influence on systemic arterial pressure in the rat

1996 ◽  
Vol 271 (5) ◽  
pp. H2108-H2115 ◽  
Author(s):  
T. B. Kuo ◽  
C. C. Yang ◽  
S. H. Chan
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Transfer Function ◽  
Arterial Pressure ◽  
Lung Volume ◽  
Systemic Arterial Pressure ◽  
High Frequency Component ◽  
Autonomic Nervous ◽  
Respiratory Pumping ◽  
Bilateral Vagotomy

We evaluated the hypothesis that fluctuations in systemic arterial pressure (SAP) are under the influence of the respiratory pumping mechanism subjected to a modulatory action by the autonomic nervous system that is exerted primarily on the heart. Computer-generated broad-band mechanical ventilation (0-3 Hz) was applied to Sprague-Dawley rats that were anesthetized with ketamine and paralyzed with pancuronium. We observed excellent coherence between lung volume and SAP signals at ventilatory rates between 0.5 and 2.5 Hz; this coherence was unaffected by phentolamine, propranolol, atropine, bilateral vagotomy, or ventilatory stroke volume at 2-4 ml. Whereas bilateral vagotomy exerted no discernible effect, propranolol elicited a significant frequency-dependent (0.5-1.5 Hz) reduction in the magnitude of lung volume-SAP and lung volume-pulse pressure transfer functions. There was also a shift toward 0 degree for the phase of the lung volume-SAP transfer function over the same frequency range. We conclude that the high-frequency component (0.8-2.4 Hz) of the SAP spectrum may be generated by the respiratory pumping mechanism. However, the lower-frequency end of this mechanical influence is subjected to additional amplification by the autonomic nervous system, in which the beta-adrenergic system played a major role via its influence on the heart.

Pulmonary vasoactive effects of exogenous and endogenous AVP in conscious dogs

1986 ◽  
Vol 251 (5) ◽  
pp. H1009-H1016
Author(s):  
D. P. Nyhan ◽  
H. S. Geller ◽  
H. M. Goll ◽  
P. A. Murray
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Arterial Pressure ◽  
Entire Range ◽  
Enzyme Inhibitor ◽  
Vena Cava ◽  
Systemic Arterial Pressure ◽  
Conscious Dogs ◽  
Similar Response ◽  
Autonomic Nervous

Our objectives were to investigate the extent to which both exogenously administered and endogenously released arginine vasopressin (AVP) exert a direct, vasoactive influence on the pulmonary circulation of conscious dogs. Multipoint pulmonary vascular pressure-cardiac index (P/Q) plots were constructed during normoxia in conscious dogs by stepwise constriction of the thoracic inferior vena cava (IVC) to reduce Q. In intact dogs, AVP infusion (7.6 ng X kg-1 X min-1 iv) increased (P less than 0.01) plasma AVP from 2.3 +/- 0.4 to 280 +/- 23 pg/ml, and increased (P less than 0.01) the pulmonary vascular pressure gradient (pulmonary arterial pressure minus pulmonary capillary wedge pressure, PAP-PCWP) over the entire range of Q studied. Following administration of autonomic nervous system antagonists and a converting-enzyme inhibitor, exogenous AVP again increased (P less than 0.01) PAP-PCWP over the entire range of Q. Generation of P/Q plots via IVC constriction resulted in systemic hypotension (58 +/- 4 mmHg) and a concomitant increase (P less than 0.01) in endogenous AVP release from 2.1 +/- 0.2 to 109 +/- 22 pg/ml. Following administration of the specific AVP receptor antagonist [d(CH2)5]AVP (10 micrograms/kg iv), systemic arterial pressure, but not PAP - PCWP, was decreased to significantly lower levels as Q was reduced during IVC constriction. A similar response was observed in dogs pretreated with the neurohumoral blockers. Thus exogenous administration of AVP results in active, non-flow-dependent pulmonary vasoconstriction. This effect is not dependent on reflex activation of the autonomic nervous system or on the increased production of angiotensin II.(ABSTRACT TRUNCATED AT 250 WORDS)

Control of blood pressure and hindlimb conductance during hemorrhage in conscious renal hypertensive rabbits

1995 ◽  
Vol 268 (6) ◽  
pp. H2302-H2310 ◽  
Author(s):  
G. Weichert ◽  
C. A. Courneya
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Angiotensin Ii ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Similar Pattern ◽  
Ang Ii ◽  
Autonomic Nervous

We examined the response to hemorrhage in conscious normotensive and hypertensive rabbits under control conditions and during efferent blockade of 1) the hormones vasopressin (AVP) and angiotensin II (ANG II), 2) the autonomic nervous system, and 3) autonomic and hormonal inputs. We recorded mean arterial pressure, heart rate, and hindlimb conductance. The response to hemorrhage was unchanged with hormonal blockade alone. Blockade of the autonomic nervous system caused a faster rate of blood pressure decline, but the rate of decrease in hindlimb conductance was maintained at control levels. Blocking the autonomic nervous system and the hormones resulted in rapid blood pressure decline and an increase in hindlimb conductance. Although the three types of efferent blockade had a similar pattern of effects in normotensive and hypertensive rabbits, hypertensive rabbits exhibited less cardiovascular support during hemorrhage than normotensive rabbits. During hemorrhage, hypertensive rabbits had an attenuation of hindlimb vasoconstriction, a reduction in the heart rate-mean arterial pressure relationship, and reduced ability to maintain blood pressure compared with normotensive rabbits.

scholarly journals Effect of dry needling on the variability of cardiac frequency in university members with temporomandibular dysfunction

2021 ◽  
Vol 10 (5) ◽  
pp. e49510515198
Author(s):  
Guilherme Pertinni de Morais Gouveia ◽  
Vinicius Ribeiro dos Santos ◽  
Felipe Andrade de Oliveira ◽  
Elisson de Sousa Mesquita Silva
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
University Students ◽  
Temporomandibular Disorders ◽  
Temporomandibular Disorder ◽  
Frequency Component ◽  
High Frequency Component ◽  
Dry Needling ◽  
Constant Increase ◽  
Autonomic Nervous

Introduction: Despite the existence of some theories about the effect of Dry Needling on pain, there is still a lack of research using this technique in the treatment of temporomandibular disorder and its repercussions on the autonomic nervous system. Therefore, the aim was to analyze the effect of Dry Needling on the autonomic modulation of university students with temporomandibular disorders. Methods: This is an interventional, inferential study, carried out with university students with temporomandibular disorders. A frequency meter was used before, during, and after the application of the dry needle to verify its short and medium term effect on the autonomic nervous system. For statistical analysis, the ANOVA test was used. Results: Twenty volunteers with an average age of 21.3 years took part in the study, most of them male (65%). When the rMSSD and pNN50 indexes were analyzed, an increase was observed during dry needling (p = 0.701 and 0.452, respectively). However, after application, these indices fell, remaining above the base values. However, the triangular RR and TINN indices showed a constant increase during collection (p = 0.578 and 0.613, respectively). The high frequency component increased during the technique (p = 0.860), but the same did not happen with the low frequency component (p = 0.693), which suffered a constant increase, even with minor variation. Conclusion: The effect of this technique promotes the improvement of the heart rate variability values, maintaining the balance of the autonomic nervous system without generating cardiovascular risks, and its effects were immediate and lasting.

Autonomic modulation of ovine fetal responses to atrial natriuretic factor infusion

1993 ◽  
Vol 265 (3) ◽  
pp. R596-R601
Author(s):  
L. A. Bayer ◽  
C. Y. Cheung ◽  
R. A. Brace
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Arterial Pressure ◽  
Atrial Natriuretic Factor ◽  
Protein Concentration ◽  
Urine Flow ◽  
Late Gestation ◽  
Plasma Protein Concentration ◽  
Autonomic Nervous

The aim of this study was to determine whether the autonomic nervous system modulates the cardiovascular, endocrine, and/or urinary responses to atrial natriuretic factor (ANF) infusion in the fetus. We infused ANF intravenously for 30 min into chronically catheterized, late-gestation sheep fetuses with autonomic blockade and compared the responses to those in autonomically intact fetuses. During the infusions, plasma ANF concentration increased similarly in the blocked and intact fetuses. Arterial pressure decreased by 2 mmHg in both groups, but the decrease occurred earlier in the blocked fetuses. Heart rate was significantly decreased by an average of 15 beats/min in the blocked compared with the intact fetuses. Plasma protein concentration decreased in the blocked fetuses compared with a rise in the intact fetuses. In the blocked fetuses, the restoration of blood volume to normal during the postinfusion period occurred earlier. In the blocked animals, low doses of ANF produced a diuresis, whereas high doses did not increase urine flow; the opposite responses occurred in the intact group. Plasma arginine vasopressin (AVP) concentration increased during the infusion only in the blocked animals. The fetal venous pressure, plasma renin activity, and norepinephrine responses were similar in both groups. These data suggest that the autonomic nervous system may play a role in modulating the fetal arterial pressure, heart rate, blood volume, plasma protein concentration, AVP, and urine flow responses to ANF. Thus the autonomic nervous system appears to significantly modulate multiple responses to ANF in the late-gestation ovine fetus.

ARTERIAL PRESSURE VARIABILITY FOR EVALUATION OF THE STRESS ON AUTONOMIC NERVOUS SYSTEM OF PATIENTS WITH CARDIAC PACING

ASAIO Journal ◽  
2002 ◽  
Vol 48 (2) ◽  
pp. 127
Author(s):  
Tatsuo Tsutsui ◽  
Tomoaki Jikuya ◽  
Yasushi Terada ◽  
Yuzuru Sakakibara ◽  
Yoshiyuki Satikai
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Arterial Pressure ◽  
Cardiac Pacing ◽  
Autonomic Nervous ◽  
Arterial Pressure Variability

scholarly journals Heart Rate Variability Using The Analgesia Nociception Index as A Predictor of Illness Severity and Mortality in Critically Ill Patients with COVID-19.

2020 ◽  
Author(s):  
Cristian Aragón-Benedí ◽  
Pablo Oliver-Forniés ◽  
Felice Galluccio ◽  
Ece Yamak Altinpulluk ◽  
Tolga Ergonenc ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
High Frequency ◽  
Frequency Component ◽  
High Frequency Component ◽  
Autonomic Nervous

Abstract Introduction A balance between the autonomic nervous system and the immune system against SARS-COV-2 is critical in the resolution of its severe macrophage proinflammatory activation. To demonstrate that most severely ill COVID-19 patients will show a depletion of the sympathetic nervous system and a predominance of parasympathetic tone. We hypothesized that a low energy of an autonomic nervous system and a high level of the high frequency component of heart rate variability may be related to the number of proinflammatory cytokines and could have a predictive value in terms of severity and mortality in critically ill patients suffering from COVID-19; Materials and Methods Single-centre, prospective, observational pilot study which included COVID-19 patients admitted to the Surgical Intensive Care Unit. High frequency (HF) component of heart rate variability (HRV) and energy of the autonomic nervous system were recorded using analgesia nociception index monitor (ANI). To estimate the severity and mortality we used the SOFA score and the date of discharge or date of death.Results A total of fourteen patients were finally included in the study. High-frequency component of heart rate variability (ANIm) were higher in the non-survivor group (p = 0.003) and were correlated with higher IL-6 levels (p = 0.002) Energy was inversely correlated with SOFA (p = 0.029). Limit value at 80 of ANIm, predicted mortalities with the sensitivity of 100% and specificity of 85.7%. In the case of energy, a limit value of 0.41 predicted mortality with all predictive values of 71.4%.Conclusion The different components of the spectral analysis of HRV allow us to infer the association between the autonomic nervous system and critically ill patients’ immune system. A low autonomic nervous system activity and a predominance of the parasympathetic system due to sympathetic depletion in patients are associated with a worse prognosis and higher mortality.

Role of the autonomic nervous system in push-pull gravitational stress in anesthetized rats

2003 ◽  
Vol 94 (2) ◽  
pp. 709-715 ◽  
Author(s):  
Amy L. Hakeman ◽  
Don D. Sheriff
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Arterial Pressure ◽  
Autonomic Function ◽  
Sprague Dawley ◽  
Autonomic Nervous ◽  
Anesthetized Rats ◽  
Gravitational Stress ◽  
Before And After ◽  
Phenylephrine Infusion

Tolerance to +Gzstress is reduced by preceding exposure to −Gz (push-pull effect). The mechanism(s) responsible for this effect are not fully understood, although the arterial baroreceptor reflexes have been implicated. We investigated the integrative response of the autonomic nervous system by studying responses to gravitational stress before and after autonomic function was inhibited by hexamethonium in 10 isoflurane-anesthetized male and female Sprague-Dawley rats. Animals were restrained supine and subjected to two rotations imposed about the x-axis: 1) a control G profile consisting of rotation from 0 Gz (+1 Gy) to 90° head-up tilt (+1 Gz) for 10 s and 2) a push-pull G profile consisting of rotation from 0 Gz to 90° head-down tilt (−1 Gz) for 2 s immediately preceding 10 s of +1 Gz stress. Eight G profiles consisting of equal numbers of control and push-pull trials were imposed by using a counterbalanced design. We found that hexamethonium lowered baseline arterial pressure and abolished the push-pull effect. The lack of a push-pull effect after autonomic blockade persisted when arterial pressure was restored to baseline levels by phenylephrine infusion. Lowering baseline arterial pressure by sodium nitroprusside infusion or by hemorrhage when autonomic function was intact also abolished the push-pull effect. We conclude that intact autonomic function and a normal baseline arterial pressure are needed for expression of the push-pull effect in anesthetized rats subjected to tilting.

Effects of Stroop color-word conflict test on the autonomic nervous system responses

1997 ◽  
Vol 272 (3) ◽  
pp. H1113-H1121 ◽  
Author(s):  
Y. Hoshikawa ◽  
Y. Yamamoto
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Spectral Analysis ◽  
Autonomic Nervous System ◽  
Lung Volume ◽  
Mental Stress ◽  
Color Word ◽  
System Activity ◽  
Autonomic Nervous ◽  
Nervous System Activity

The Stroop color-word test (CWT) is a mental stress test involving sensory rejection and has been used as a model of the defense reaction in humans. The present study was designed to investigate effects of CWT on resting cardiac autonomic nervous system activity evaluated by analyses of heart rate (HR) variability (HRV). Eight healthy subjects performed 21 min of CWT after 14 min of resting control followed by 14 min of recovery (RCV). Beat-to-beat R-R intervals (RRI, i.e., HRV), systolic blood pressure (SBP), and instantaneous lung volume were continuously monitored throughout these periods. Steady-state HRV data (10-12 min) for resting control and recovery (12 min) and for 1-11 min (CWT1) and 11-21 min (CWT2) of CWT were analyzed by coarse-graining spectral analysis to break down their total power into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low (0.0-0.15 Hz, LF)- and high (>0.15 Hz, HF)-frequency components. Cardiac sympathetic (SNS) and parasympathetic (PNS) nervous system activity indicators were evaluated as LF/HF and HF/TP, respectively [LF, HF, and total spectral power (TP) of HRV]. The fractal component had the spectrum of 1/f(beta), and the spectral exponent beta was calculated. RRI decreased and SBP, plasma norepinephrine, and epinephrine concentrations increased significantly (P < 0.05) in response to CWT (CWT1 and CWT2). PNS and SNS indicators did not show any significant (P > 0.05) difference between resting controls and CWT. Whereas the percentage of fractal components in total HRV remained unchanged, beta decreased significantly (P < 0.05) in response to CWT. Transfer magnitudes from SBP to RRI, calculated by cross-spectral analysis, decreased at CWT2. The transfer magnitudes from instantaneous lung volume to RRI were also decreased significantly (P < 0.05) by CWT. It was concluded that although CWT did not affect the SNS indicator of HRV, despite altered HR and vasomotor responses, tonic sympathetic nervous system influence was observed for norepinephrine and epinephrine. In addition, reflex blood pressure (CWT2) and respiratory modulation of HR (CWT1 and CWT2) decreased during CWT. Mental stress altered the fractal nature of HRV (as judged by decreased beta), but mechanism(s) responsible for this change remained unknown.

Systemic hemodynamic responses to chronic angiotensin II infusion into the renal artery of dogs

1997 ◽  
Vol 273 (6) ◽  
pp. R1980-R1989 ◽  
Author(s):  
Sharyn M. Fitzgerald ◽  
Kathleen M. Stevenson ◽  
Roger G. Evans ◽  
Warwick P. Anderson
Keyword(s):  
Nervous System ◽  
Cardiac Output ◽  
Autonomic Nervous System ◽  
Angiotensin Ii ◽  
Arterial Pressure ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Systemic Hemodynamics ◽  
Autonomic Ganglion ◽  
Autonomic Nervous

Chronic intrarenal infusion of angiotensin II (0.5 ng ⋅ kg−1⋅ min−1) in dogs increases arterial pressure. In the present study we determined whether this was associated with changes in cardiac output or in total peripheral resistance. Mean arterial pressure did not change initially but was significantly increased over days 14- 28 of the infusion period (+6 ± 2 mmHg), as was total peripheral resistance (+4 ± 2 mmHg ⋅ min ⋅ l−1). Neither cardiac output, renal blood flow, nor glomerular filtration rate was significantly changed over this period. To determine the influence of the autonomic nervous system on the developing hypertension, periodic acute autonomic ganglion blockade was performed. Before angiotensin II infusion ganglion blockade reduced total peripheral resistance and increased cardiac output, and this effect was similar across the 4 wk of angiotensin II infusion. Systemic hemodynamics were not affected by intravenous angiotensin II infusion (0.5 ng ⋅ kg−1⋅ min−1). Thus intrarenal infusion of low-dose angiotensin II produced a chronic increase in arterial pressure due to an action within the kidney. The hypertension was associated with increased total peripheral resistance but not with marked changes in cardiac output or renal function or in the influence of the autonomic nervous system on systemic hemodynamics.

Cardiovascular effects of 1,8-cineole, a terpenoid oxide present in many plant essential oils, in normotensive rats

2002 ◽  
Vol 80 (12) ◽  
pp. 1125-1131 ◽  
Author(s):  
Saad Lahlou ◽  
André Fernandes Figueiredo ◽  
Pedro Jorge Caldas Magalhães ◽  
José Henrique Leal-Cardoso
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Essential Oils ◽  
Thoracic Aorta ◽  
Cardiovascular Effects ◽  
Aortic Pressure ◽  
Plant Essential Oils ◽  
Conscious Rats ◽  
Autonomic Nervous ◽  
Bilateral Vagotomy

The cardiovascular effects of i.v. treatment with 1,8-cineole, a monoterpenic oxide present in many plant essential oils, were investigated in normotensive rats. This study examined (i) whether the autonomic nervous system is involved in the mediation of 1,8-cineole-induced changes in mean aortic pressure (MAP) and heart rate (HR) and (ii) whether the hypotensive effects of 1,8-cineole could result from its vasodilatory effects directly upon vascular smooth muscle. In both pentobarbital-anesthetized and conscious, freely moving rats, bolus injections of 1,8-cineole (0.3–10 mg/kg, i.v.) elicited similar and dose-dependent decreases in MAP. Concomitantly, 1,8-cineole significantly decreased HR only at the highest dose (10 mg/kg). Pretreatment of anesthetized rats with bilateral vagotomy significantly reduced the bradycardic responses to 1,8-cineole (10 mg/kg) without affecting hypotension. In conscious rats, i.v. pretreatment with methylatropine (1 mg/kg), atenolol (1.5 mg/kg), or hexamethonium (30 mg/kg) had no significant effects on the 1,8-cineole-induced hypotension, while bradycardic responses to 1,8-cineole (10 mg/kg) were significantly reduced by methylatropine. In rat isolated thoracic aorta preparations, 1,8-cineole (0.006–2.6 mM) induced a concentration-dependent reduction of the contraction induced by potassium (60 mM). This is the first physiological evidence that i.v. treatment with 1,8-cineole in either anesthetized or conscious rats elicits hypotension; this effect seems related to an active vascular relaxation rather than withdrawal of sympathetic tone.Key words: 1,8-cineole, essential oil, cardiovascular effects, autonomic nervous system, isolated thoracic aorta.

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