Stimulation parameters for cardiovascular responses from medulla and hypothalamus

1963 ◽  
Vol 205 (3) ◽  
pp. 601-605 ◽  
Author(s):  
Robert J. Wilkus ◽  
Clarence N. Peiss
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular Responses ◽  
Maximal Response ◽  
Response Curves ◽  
High Frequencies ◽  
Threshold Response ◽  
Stimulation Parameters ◽  
Wide Range ◽  
Alpha Chloralose

Electrical stimulation was carried out in the medulla and hypothalamus of 33 vagotomized cats anesthetized with alpha-chloralose. A wide range of stimulation frequencies was used at pulse durations of 2.0, 0.2, and 0.02 msec. The lowest frequency at which the majority of animals reach a maximal response in heart rate or blood pressure was 100 cycles/sec at all three pulse durations. At 2 msec pulse duration, the response declined by 30% at 225 cycles/sec. At pulse durations of 0.2 and 0.02 msec, 30% decline in response occurred, respectively, at 1,040 and 1,250 cycles/sec. The response curves were essentially similar for both heart rate and blood pressure. Strength-duration curves, using a 3% change in heart rate as a threshold response, showed a similarity in the curves for fibers mediating sympathetic acceleration and those mediating sympathetic inhibition of heart rate. The decline in response at high frequencies does not appear to be due to transmitter depletion. The basis for optimal frequency of 100 cycles/sec and for declining responses at higher frequencies is discussed.

Cardiovascular Responses to Muscle Stretching: A Systematic Review and Meta-analysis

2021 ◽  
Author(s):  
Ewan Thomas ◽  
Marianna Bellafiore ◽  
Ambra Gentile ◽  
Antonio Paoli ◽  
Antonio Palma ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular System ◽  
Vascular Function ◽  
Meta Analysis ◽  
Random Effect ◽  
Cardiovascular Responses ◽  
Qualitative Description ◽  
Cross Sectional ◽  
Quantitative Synthesis

AbstractThe aim of this study will be to review the current body of literature to understand the effects of stretching on the responses of the cardiovascular system. A literature search was performed using the following databases: Scopus, NLM Pubmed and ScienceDirect. Studies regarding the effects of stretching on responses of the cardiovascular system were investigated. Outcomes regarded heart rate(HR), blood pressure, pulse wave velocity (PWV of which baPWV for brachial-ankle and cfPWV for carotid-femoral waveforms), heart rate variability and endothelial vascular function. Subsequently, the effects of each outcome were quantitatively synthetized using meta-analytic synthesis with random-effect models. A total of 16 studies were considered eligible and included in the quantitative synthesis. Groups were also stratified according to cross-sectional or longitudinal stretching interventions. Quality assessment through the NHLBI tools observed a “fair-to-good” quality of the studies. The meta-analytic synthesis showed a significant effect of d=0.38 concerning HR, d=2.04 regarding baPWV and d=0.46 for cfPWV. Stretching significantly reduces arterial stiffness and HR. The qualitative description of the studies was also supported by the meta-analytic synthesis. No adverse effects were reported, after stretching, in patients affected by cardiovascular disease on blood pressure. There is a lack of studies regarding vascular adaptations to stretching.

A Comparison of the Acute Haemodynamic Effects of Propranolol and Pindolol at Rest and during Supine Exercise in Man

1980 ◽  
Vol 59 (s6) ◽  
pp. 465s-468s ◽  
Author(s):  
T. L. Svendsen ◽  
J. E. Carlsen ◽  
O. Hartling ◽  
A. McNair ◽  
J. Trap-Jensen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Pulmonary Artery ◽  
Pulmonary Artery Pressure ◽  
Response Curves ◽  
Receptor Blocking ◽  
Artery Pressure ◽  
Arterial Blood ◽  
Β Receptor

1. Dose-response curves for heart rate, cardiac output, arterial blood pressure and pulmonary artery pressure were obtained in 16 male patients after intravenous administration of three increasing doses of pindolol, propranolol or placebo. All patients had an uncomplicated acute myocardial infarction 6–8 months earlier. 2. The dose-response curves were obtained at rest and during repeated bouts of supine bicycle exercise. The cumulative dose amounted to 0.024 mg/kg body weight for pindolol and to 0.192 mg/kg body weight for propranolol. 3. At rest propranolol significantly reduced heart rate and cardiac output by 12% and 15% respectively. Arterial mean blood pressure was reduced by 9.2 mmHg. Mean pulmonary artery pressure increased significantly by 2 mmHg. Statistically significant changes in these variables were not seen after pindolol or placebo. 4. During exercise pindolol and propranolol both reduced cardiac output, heart rate and arterial blood pressure to the same extent. After propranolol mean pulmonary artery pressure was increased significantly by 3.6 mmHg. Pindolol and placebo did not change pulmonary artery pressure significantly. 5. The study suggests that pindolol may offer haemodynamic advantages over β-receptor-blocking agents without intrinsic sympathomimetic activity during low activity of the sympathetic nervous system, and may be preferable in situations where the β-receptor-blocking effect is required only during physical or psychic stress.

Cardiovascular responses to head-stand posture

1963 ◽  
Vol 18 (5) ◽  
pp. 987-990 ◽  
Author(s):  
Shanker Rao
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
High Pressure ◽  
Blood Flow ◽  
Arterial Pressure ◽  
Skin Temperature ◽  
Cardiovascular Responses ◽  
Posterior Tibial Artery ◽  
Nervous Control ◽  
Posterior Tibial

Reports of cardiovascular responses to head-stand posture are lacking in literature. The results of the various responses, respectively, to the supine, erect, and head-stand posture, are as follows: heart rate/min 67, 84, and 69; brachial arterial pressure mm Hg 92, 90, and 108; posterior tibial arterial pressure mm Hg 98, 196, and 10; finger blood flow ml/100 ml min 4.5, 4.4, and 5.2; toe blood flow ml/100 ml min 7.1, 8.1, and 3.4; forehead skin temperature C 34.4, 34.0 and 34.3; dorsum foot skin temperature C 28.6, 28.2, and 28.2. It is inferred that the high-pressure-capacity vessels between the heart level and posterior tibial artery have little nervous control. The high-pressure baroreceptors take active part in postural adjustments of circulation. The blood pressure equating mechanism is not as efficient when vital tissues are pooled with blood as when blood supply to them is reduced. man; heart rate; blood flow; skin temperature Submitted on January 3, 1963

Role of paraventricular and supraoptic nuclei in central cardiovascular regulation in the cat

1980 ◽  
Vol 239 (1) ◽  
pp. R137-R142 ◽  
Author(s):  
J. Ciriello ◽  
F. R. Calaresu
Keyword(s):  
Heart Rate ◽  
Cardiovascular Responses ◽  
Inhibitory Influence ◽  
Sympathetic Nervous Systems ◽  
Aortic Depressor Nerve ◽  
Bilateral Lesions ◽  
Alpha Chloralose ◽  
Supraoptic Nuclei ◽  
Stimulation Of

To investigate the role of the paraventricular (PAH) and supraoptic (SON) nuclei in regulation of the cardiovascular system experiments were done in 26 cats anesthetized with alpha-chloralose, paralyzed, and artificially ventilated. Electrical stimulation of histologically verified sites in the region of the PAH and SON elicited increases in arterial pressure in bilaterally vagotomized animals and increases in heart rate both in spinal (C2) animals and in animals bilaterally vagotomized, In addition, stimulation of either the PAH or SON inhibited the reflex vagal bradycardia elicited by stimulation of the carotid sinus nerve (CSN) and bilateral lesions of these areas increased the magnitude of the response. On the other hand, stimulation and lesions of these hypothalamic regions did not alter the magnitude of the cardiovascular responses to stimulation of the aortic depressor nerve. These results demonstrate that stimulation of the PAH and SON elicit cardiovascular responses due to reciprocal changes in activity of the parasympathetic and sympathetic nervous systems and that these structures maintain a tonic inhibitory influence on the heart rate component of the CSN reflex.

scholarly journals Tai-chi-chuan and yoga onpostexercise hypotension: comparison to aerobic and resistance exercise

2016 ◽  
Vol 29 (3) ◽  
pp. 543-552
Author(s):  
João Douglas Alves ◽  
Jorge Luiz de Brito Gomes ◽  
Caio Victor Coutinho de Oliveira ◽  
José Victor de Miranda Henriques Alves ◽  
Fabiana Ranielle de Siqueira Nogueira ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Young Women ◽  
Tai Chi ◽  
Cardiovascular Effects ◽  
Cardiovascular Responses ◽  
Tai Chi Chuan ◽  
Post Exercise ◽  
Significant Difference ◽  
Apparently Healthy

Abstract Introduction: Tai-Chi-Chuan and Yoga have becoming popular practices. However is unclear the cardiovascular effects, and if they present similar behavior to aerobic and resistance sessions. Objective: To evaluate the cardiovascular responses during the session and post-exercise hypotension (PEH) of Tai Chi Chuan (TS) and Yoga (YS) in comparison to aerobic (AS) and resistance (SR) exercises. Methods: Fourteen young women (22.3 ± 2 years) apparently healthy performed four sessions (AS, RS, TS and YS). The heart rate (HR), systolic (SBP) and diastolic blood pressure (DBP) were recorded at resting, during (every 10 minutes) and until 50 minutes of recovery. Results: AS, RS, TS e YS showed significant increase in HR compared to resting.AS at 10, 30 e 50 minutes in relation to RS, TS e YS. The RS in relation to TS and YS at 10, 30 and 50 minutes. No significant difference between TS and YS. SBP was significantly increased in AS, RS, TS e YS at 10, 30 e 50 minutes during the session, in relation to rest. AS was significantly higher at 30 e 50 minutes than RS and higher than TS and YS at 10, 30 e 50 minutes. No significant difference in DBP. For PEH, AS, RS and TS significantly reduced at 10, 30 and 50 minutes. YS reduced at 50 minutes. No significant diastolic PEH. Conclusion: TS and YS showed as safe alternatives of exercising in the normotensive young adult woman, despite having lower values, they promote similar hemodynamic behavior to AS and RS.

Ascending pathways mediating somatoautonomic reflexes in exercising dogs

1987 ◽  
Vol 62 (3) ◽  
pp. 1186-1191 ◽  
Author(s):  
J. W. Kozelka ◽  
G. W. Christy ◽  
R. D. Wurster
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Surgical Techniques ◽  
Arterial Occlusion ◽  
Cardiovascular Responses ◽  
Spinal Pathways ◽  
Arterial Blood ◽  
Bilateral Carotid ◽  
Dorsolateral Funiculus ◽  
Carotid Arterial

The ascending spinal pathways mediating somatocardiovascular reflexes during exercise were studied in unanesthetized dogs by placing lesions in the lumbar spinal cord. After training to run on a treadmill with hindlimbs only, 20 dogs were anesthetized and instrumented using sterile surgical techniques. To chronically record heart rate and arterial blood pressure, the aorta was cannulated via the omocervical artery. To test the intactness of descending spinal sympathetic pathways, reflex pressor responses to baroreceptor hypotension were produced by bilateral carotid arterial occlusion using pneumatic vessel occluders placed around the common carotid arteries. To generate transient ischemic exercise (120 s), a pneumatic occluder was placed around the left iliac artery. Eight to 10 days after instrumentation, blood pressure and heart rate were monitored at rest and during hindlimb running with and without simultaneous iliac arterial occlusion. The modest pressor response and tachycardia elicited by hindlimb exercise were markedly augmented by simultaneous hindlimb ischemia (i.e., iliac arterial occlusion). Lesion placement in the dorsolateral sulcus area and the dorsolateral funiculus at L2 significantly reduced the blood pressure and heart rate responses to simultaneous exercise occlusion. The cardiovascular responses to nonischemic exercise and bilateral carotid arterial occlusion were not altered by such spinal sections. It is concluded that in the dog the ascending spinal pathways mediating cardiovascular responses to ischemic exercise are located in the lateral funiculus, including the dorsolateral sulcus area and dorsolateral funiculus.

Reciprocal rat chromosome 2 congenic strains reveal contrasting blood pressure and heart rate QTL

2002 ◽  
Vol 10 (3) ◽  
pp. 199-210 ◽  
Author(s):  
Adamu Alemayehu ◽  
Laura Breen ◽  
Drahomira Krenova ◽  
Morton P. Printz
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spontaneously Hypertensive Rat ◽  
Cardiovascular Responses ◽  
Chromosome 2 ◽  
Spontaneously Hypertensive ◽  
Congenic Strains ◽  
Multiple Blood ◽  
Wistar Kyoto ◽  
Chromosome Segments

Evidence exists implying multiple blood pressure quantitative trait loci (QTL) on rat chromosome 2. To examine this possibility, four congenic strains and nine substrains were developed with varying size chromosome segments introgressed from the spontaneously hypertensive rat (SHR/lj) and normotensive Wistar-Kyoto rat (WKY/lj) onto the reciprocal genetic background. Cardiovascular phenotyping was conducted with telemetry over extended periods during standard salt (0.7%) and high-salt (8%) diets. Our results are consistent with at least three independent pressor QTL: transfer of SHR/lj alleles to WKY/lj reveals pressor QTL within D2Rat21-D2Rat27 and D2Mgh10-D2Rat62, whereas transfer of WKY/lj D2Rat161-D2Mit8 to SHR/lj reveals a depressor locus. Our results also suggest a depressor QTL in SHR/lj located within D2Rat161-D2Mgh10. Introgressed WKY/lj segments also reveal a heart rate QTL within D2Rat40-D2Rat50 which abolished salt-induced bradycardia, dependent upon adjoining SHR/lj alleles. This study confirms the presence of multiple blood pressure QTL on chromosome 2. Taken together with our other studies, we conclude that rat chromosome 2 is rich in alleles for cardiovascular and behavioral traits and for coordinated coupling between behavior and cardiovascular responses.

Acute Cardiovascular Responses to Self-selected Intensity Exercise in Parkinson's Disease

2021 ◽  
Author(s):  
Hélcio Kanegusuku ◽  
Gabriel Grizzo Cucato ◽  
Paulo Longano ◽  
Erika Okamoto ◽  
Maria Elisa Pimentel Piemonte ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Parkinson’S Disease ◽  
Heart Rate ◽  
Parkinson's Disease ◽  
Pulse Wave ◽  
Augmentation Index ◽  
Cardiovascular Responses ◽  
Cycle Ergometer ◽  
Control Session ◽  
Wave Analysis

AbstractParkinson’s disease patients frequently present cardiovascular dysfunction. Exercise with a self-selected intensity has emerged as a new strategy for exercise prescription aiming to increase exercise adherence. Thus, the current study evaluated the acute cardiovascular responses after a session of aerobic exercise at a traditional intensity and at a self-selected intensity in Parkinson’s disease patients. Twenty patients (≥ 50 years old, Hoehn & Yahr 1–3 stages) performed 3 experimental sessions in random order: Traditional session (cycle ergometer, 25 min, 50 rpm, 60–80% maximum heart rate); Self-selected intensity: (cycle ergometer, 25 min, 50 rpm with self-selected intensity); and Control session (resting for 25 min). Before and after 30 min of intervention, brachial and central blood pressure (auscultatory method and pulse wave analysis, respectively), cardiac autonomic modulation (heart rate variability), and arterial stiffness (pulse wave analysis) were evaluated. Brachial and central systolic and diastolic blood pressure, heart rate, and the augmentation index increased after the control session, whereas no changes were observed after the exercise sessions (P<0.01). Pulse wave velocity and cardiac autonomic modulation parameters did not change after the three interventions. In conclusion, a single session of traditional intensity or self-selected intensity exercises similarly blunted the increase in brachial and central blood pressure and the augmentation index compared to a non-exercise control session in Parkinson’s disease patients.

Measurement of sympathetic nerve activity in the unanesthetized rat

1989 ◽  
Vol 67 (1) ◽  
pp. 250-255 ◽  
Author(s):  
J. P. Fluckiger ◽  
G. Gremaud ◽  
B. Waeber ◽  
A. Kulik ◽  
A. Ichino ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Pressure ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Blood Pressure Reduction ◽  
Response Curves ◽  
Nerve Activity ◽  
Dose Dependent

A new system was developed in our laboratory to continuously monitor intra-arterial pressure, heart rate, and sympathetic nerve activity in unanesthetized rats. The animals were prepared 24 h before the start of the experiments. Sympathoneural traffic was measured at the level of splanchnic nerve. The amplitude of the spikes recorded at this level was utilized to express sympathetic nerve activity. The amplitude of the residual electroneurogram signal present 30 min after the rats were killed was 32 +/- 2 mV (mean +/- SE; n = 11). For analysis, these background values were subtracted from values determined in vivo. The nerve we studied contains postganglionic fibers, since electrical activity decreased in response to ganglionic blockade with pentolinium (1.25 mg/min iv for 4 min). The amplitude of spikes fell by 43 +/- 4% (n = 4). Sympathetic nerve activity was highly reproducible at a 24-h interval (104 +/- 26 vs. 111 +/- 27 mV for the amplitude of spikes; n = 11). Dose-response curves to the alpha 1-stimulant methoxamine and to bradykinin were established in four rats. The increase in blood pressure induced by methoxamine caused a dose-dependent fall in sympathetic nerve activity, whereas the blood pressure reduction resulting from bradykinin was associated with a dose-dependent activation of sympathetic drive. These data therefore indicate that it is possible with out system to accurately measure sympathetic nerve activity in the awake rat, together with intra-arterial pressure and heart rate.

Autonomic mechanisms underlying area postrema stimulation-induced cardiovascular responses in rats

1991 ◽  
Vol 261 (1) ◽  
pp. R1-R8 ◽  
Author(s):  
A. V. Ferguson ◽  
P. Smith
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Rate Control ◽  
Area Postrema ◽  
Cardiovascular Responses ◽  
Pressure Control ◽  
Blocking Agent ◽  
Adrenergic Blockade ◽  
Neural Pathways ◽  
Heart Rate Control

Experiments were designed to examine the autonomic mechanisms underlying the decreases in blood pressure and heart rate elicited by electrical stimulation in the rat area postrema (AP). Vagotomy was found to significantly reduce the bradycardia observed in response to AP stimulation (control -123.5 +/- 23.5 beats/min; vagotomized -7 +/- 5.4 beats/min; P less than 0.001) but was without significant effect on blood pressure responses. Hexamethonium significantly reduced both heart rate (control -225.5 +/- 11.9 beats/min; hexamethonium -5.5 +/- 2.8 beats/min; P less than 0.001) and depressor (control -35.4 +/- 4.7 mmHg; hexamethonium -6.4 +/- 0.8 mmHg; P less than 0.001) responses to such stimulation, whereas combined alpha- and beta-adrenergic blockade was without effect. The muscarinic blocking agent atropine also abolished both blood pressure (control -22.0 +/- 4.3 mmHg; atropine 2.8 +/- 4.4 mmHg; P less than 0.01) and heart rate (control -187.0 +/- 41.9 beats/min; atropine 8.8 +/- 2.6 beats/min; P less than 0.01) responses to AP stimulation. These data suggest that AP stimulation influences two separate neural pathways eliciting distinct cardiovascular responses. It would appear that activation of one of these pathways results in activation of vagal efferents to the heart and thus bradycardia. A second parallel pathway influenced by AP stimulation apparently elicits depressor response through actions on cholinergic muscarinic receptors.

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