SOME RESPIRATORY AND CARDIOVASCULAR EFFECTS OF GRADUAL SARIN POISONING IN THE RAT

1961 ◽  
Vol 39 (6) ◽  
pp. 1001-1011 ◽  
Author(s):  
W. C. Stewart ◽  
D. H. McKay
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Gastrocnemius Muscle ◽  
Artificial Ventilation ◽  
Cardiovascular Effects ◽  
Vagus Nerves ◽  
Toxic Dose ◽  
Circulatory Insufficiency ◽  
Slow Intravenous Infusion ◽  
Stimulation Of

Anesthetized rats were given sarin (isopropyl methylphosphonofluoridate) by slow intravenous infusion, while respiration, blood pressure, heart rate, and contractions of the gastrocnemius muscle in response to stimulation of the sciatic nerve were recorded.When artificial ventilation was not carried out, breathing stopped after a toxic dose of sarin had been given, even though the blood pressure was above normal and neuromuscular conduction was not impaired. On the other hand, when artificial ventilation was provided after breathing stopped, the blood pressure and heart rate fell, and death was apparently caused by circulatory insufficiency.Infusion of sarin caused slowing of the heart rate which was not prevented by previous section of the vagus nerves. Injection of atropine restored the heart rate to normal, and enabled the animals to withstand large doses of sarin as long as artificial ventilation was maintained.It was concluded that sarin caused a cholinergic circulatory collapse which was the cause of death in rats maintained with artificial ventilation. This circulatory insufficiency was alleviated by large doses of atropine. Possible causes of the depression of circulation are discussed, and reasons are given for believing it to be due mainly to cholinergic diminution of cardiac output, caused by accumulation of acetylcholine in the heart.

Static muscular contraction elicits a pressor reflex in the chicken

1997 ◽  
Vol 272 (3) ◽  
pp. R759-R765 ◽  
Author(s):  
I. C. Solomon ◽  
T. P. Adamson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Sciatic Nerve ◽  
Arterial Pressure ◽  
Gastrocnemius Muscle ◽  
Muscular Contraction ◽  
Arterial Blood ◽  
Static Contraction ◽  
Stimulation Of

Static muscular contraction has been shown to increase arterial blood pressure and heart rate in humans and other mammals. It is not clear, however, whether birds exhibit a similar response to this maneuver. Therefore, we designed these experiments to determine if the chicken exhibits a cardiovascular response to static muscular contraction and if the observed responses are evoked through a reflex involving muscle afferents. Static contraction of the gastrocnemius muscle was evoked by electrically stimulating the sciatic nerve at 1.5-3.0 times motor threshold (30-40 Hz; 0.025 ms) in 13 chloralose-anesthetized cockerels. We measured arterial blood pressure and muscle tension before and during static contraction and calculated mean arterial pressure and heart rate from the arterial pressure trace. We found that static contraction of the gastrocnemius muscle increased mean arterial pressure from 71 +/- 4 to 95 +/- 4 mmHg (P < 0.05) and increased heart rate from 304 +/- 8 to 345 +/- 10 beats/min (P < 0.05). Furthermore, we found that stimulation of the sciatic nerve after paralysis of the birds with vecuronium bromide or stimulation of the cut peripheral end of the sciatic nerve (using the same stimulation parameters described above) evoked no change in mean arterial pressure or heart rate. We conclude that static muscular contraction of the gastrocnemius muscle in the chicken elicits a pressor response and that this response is due to a reflex arising from the contracting muscles.

Increased Pressor Responsiveness to Enkephalin in Spontaneously Hypertensive Rats: The Role of Vasopressin

1980 ◽  
Vol 59 (s6) ◽  
pp. 235s-237s ◽  
Author(s):  
R. W. Rockhold ◽  
J. T. Crofton ◽  
L. Share
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pressor Response ◽  
Cardiovascular Effects ◽  
Hypertensive Rats ◽  
Methionine Enkephalin ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto Rats ◽  
Wistar Kyoto

1. The cardiovascular effects of an enkephalin analogue were examined in spontaneously hypertensive and normotensive Wistar-Kyoto rats. (D-Ala2)-methionine enkephalin caused a biphasic increase in blood pressure and an increase in heart rate after intracerebroventricular injection. 2. The initial pressor response to (D-Ala2)-methionine enkephalin was greater in hypertensive than in normotensive rats. No difference was noted between groups during the secondary pressor response. Heart rate increases paralleled the secondary increase in blood pressure. 3. Naloxone pretreatment abolished the secondary increase in blood pressure and the tachycardia, but did not blunt the initial pressor response in female Wistar-Kyoto rats. 4. Plasma levels of arginine vasopressin were depressed during the plateau phase of the pressor response in hypertensive rats given intracerebroventricular (d-Ala2)-methionine enkephalin. 5. The results suggest that the cardiovascular effects of central enkephalin are not due to vasopressin, but may involve activation of the sympathetic nervous system.

Cardiovascular Effects of Aerobic Exercise With Self-Selected or Predetermined Intensity in Adolescents With Obesity

2021 ◽  
pp. 1-7
Author(s):  
Tércio A.R. Barros ◽  
Wagner L. do Prado ◽  
Thiago R.S. Tenório ◽  
Raphael M. Ritti-Dias ◽  
Antônio H. Germano-Soares ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Body Mass Index ◽  
Heart Rate ◽  
Pulse Pressure ◽  
Exercise Intensity ◽  
Pulse Wave ◽  
Augmentation Index ◽  
Cardiovascular Effects ◽  
Heart Rate Reserve ◽  
Central Pulse Pressure

This study compared the effects of self-selected exercise intensity (SEI) versus predetermined exercise intensity (PEI) on blood pressure (BP) and arterial stiffness in adolescents with obesity. A total of 37 adolescents, 14.7 (1.6) years old, body mass index ≥95th percentile were randomly allocated into SEI (n = 18; 12 boys) or PEI (n = 19; 13 boys). Both groups exercised for 35 minutes on a treadmill, 3 times per week, for 12 weeks. The SEI could set the speed at the beginning of the sessions and make changes every 5 minutes. The PEI adolescents were trained at an intensity set at 60% to 70% of heart rate reserve. Brachial and central BP, pulse pressure, augmentation index, and carotid–femoral pulse wave were determined at baseline and after 12 weeks. Both groups reduced brachial systolic BP (SEI, Δ = −9 mm Hg; PEI, Δ = −4 mm Hg; P < .01), central systolic BP (SEI, Δ = −4 mm Hg; PEI, Δ = −4 mm Hg; P = .01), and central pulse pressure (SEI, Δ = −4 mm Hg; PEI, Δ = −3 mm Hg; P = .02) without differences between groups. No changes in the augmentation index and carotid–femoral pulse wave were observed in either group. The SEI induced similar changes in various cardiovascular outcomes compared with PEI in adolescents with obesity.

scholarly journals Cardiovascular effects of lumbar epidural anaesthesia in isoflurane-anaesthetised pigs during surgical removal of the liver

2009 ◽  
Vol 80 (1) ◽  
Author(s):  
G.F. Stegmann
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Abdominal Surgery ◽  
Epidural Anaesthesia ◽  
Cardiovascular Effects ◽  
Surgical Removal ◽  
Arterial Blood ◽  
Combined Administration ◽  
Lumbar Epidural Anaesthesia ◽  
Surgical Preparation

In humans the combined administration of epidural anaesthesia and inhalation anaesthesia may result in cardiovascular instability associated with decreases in heart rate and blood pressure. Anaesthesia was induced with a combination of midazolam / ketamine in 18 female pigs with a mean body weight of 24.9±5.9 kg scheduled for surgical removal of the liver. After tracheal intubation, anaesthesia was maintained on a circle rebreathing circuit with isoflurane. Epidural anaesthesia was administered with ropivacaine (AL-group, n=8) at 0.2 mℓ / kg of a 7.5 mg / mℓ solution to the anaesthetised animals. The A-group (n = 10) received isoflurane anaesthesia only. The vaporiser was set at 2.5 % for the A-group and 1.5 % for the AL-group. Heart rate, invasive systolic, diastolic, and mean arterial blood pressure were monitored. Comparisons were made between treatments and within treatments comparing variables during surgical preparation and abdominal surgery. Differences between treatments were not statistically significant (P > 0.05) during surgical preparation or during abdominal surgery. For within treatment groups, the differences between surgical preparation and abdominal surgery were statistically significant (P < 0.05) for heart rate in the A-group, but not statistically significant (P > 0.05) for the other variables. It is concluded that abdominal surgery may be associated with statistically significant changes in heart rate in isoflurane-anaesthetised pigs and that the combined administration of epidural ropivacaine may prevent statistically significant changes in HR during abdominal surgery.

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.

scholarly journals Does 20 mg long-acting methylphenidate alter blood pressure and heart rate in children with ADHD?

2011 ◽  
Vol 51 (5) ◽  
pp. 282
Author(s):  
Tjhin Wiguna ◽  
Sasanto Wibisono ◽  
Sudigdo Sastroasmoro ◽  
Fransiscus D. Suyatna
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular Effects ◽  
Children With Adhd ◽  
Normal Ranges ◽  
Blood Pressures ◽  
Drug Naïve ◽  
Repeated Analysis ◽  
Long Acting

Objective To identify the cardiovascular effects of long-acting methylphenidate administered for twelve weeks in Indonesian children with ADHD.Methods This was an 18-week, time series study on children with ADHD who were given 20 mg of long-acting methylphenidate for twelve weeks. During the study period we made ten serial observations of the subjects, including before, during and 6 weeks following drug administration. We included drug naive children with ADHD between the ages of 7 – 10 years. Children with mental retardation and chronic physical or mental disorders were excluded. Blood pressure was measured by sphygmomanometer with a child’s cuff at the brachial artery. We also collected data on heart rate, side effects, complaints and other medications used during the study. Repeated analysis was performed on the data with a P level of 0.05.Results Twenty-one subjects were recruited for this study. Mean blood pressure fluctuated insignificantly during the research period, for both mean systolic and mean diastolic blood pressures (P=0.115 and P=0.059). Mean heart rate also fluctuated insignificantly (P=0.091). All fluctuations were within the normal ranges. During the study, there were complaints of dizziness, nausea, and gastrointestinal upset, but they were reportedly mild and disappeared before the second week of observation.Conclusion Administration of 20 mg long-acting methylphenidate for twelve weeks in children with ADHD altered mean blood pressures and heart rates, but within the normal range for children of their age. However, cardiovascular risk observation is still needed when administering methylphenidate to children with ADHD, especially for those using the medication long-term.[Paediatr Indones. 2011;51:282-7].

scholarly journals Evaluation of the Cardiovascular Effects of Clonidine in Neonates Treated for Neonatal Abstinence Syndrome

2018 ◽  
Vol 23 (6) ◽  
pp. 473-478
Author(s):  
Raymond P. Meddock ◽  
Deirdre Bloemer
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Diastolic Blood Pressure ◽  
Neonatal Intensive Care ◽  
Dose Range ◽  
Safety Data ◽  
Cardiovascular Effects ◽  
Neonatal Abstinence Syndrome ◽  
Abstinence Syndrome

OBJECTIVES Neonatal abstinence syndrome (NAS) is characterized by withdrawal symptoms in neonates exposed to legal or illegal substances in utero, and it is often managed with medications such as opiates, phenobarbital, and clonidine. Clonidine use is increasing, but further safety data regarding its use in neonates are warranted. This study evaluated the effects of clonidine on heart rate and blood pressure in neonates treated for NAS at doses up to 24 mcg/kg/day. METHODS A retrospective review via the electronic medical record of infants at least 35 weeks' gestation treated adjunctively with clonidine for NAS in the neonatal intensive care unit at St Elizabeth was conducted. Heart rate, and systolic and diastolic blood pressure were recorded at baseline, while on different dose ranges of clonidine (small: ≤1.5 mcg/kg per dose every 3 hours; medium: &gt;1.5 to 2 mcg/kg per dose every 3 hours; and large: &gt;2 mcg/kg to 3 mcg/kg per dose every 3 hours), and upon discontinuation. RESULTS A total of 64 infants treated with clonidine for NAS between August 2015 and December 2016 were included. Heart rate decreased in all clonidine dose ranges compared with baseline (average reduction of 7 bpm [CI: −12 to −2], 9 bpm [CI: −16 to −2], and 10 bpm [CI: −18 to −1] for the small, medium, and large dose ranges, respectively; p &lt; 0.0001). Systolic and diastolic blood pressure were not significantly different from baseline when infants were receiving any dose of clonidine, except diastolic blood pressure while on medium–dose range clonidine, where diastolic blood pressure was higher than baseline (p = 0.0128). Increases in systolic and diastolic blood pressure were evident upon discontinuation of clonidine (p &lt; 0.0001 and p = 0.0156, respectively). CONCLUSIONS Clonidine doses up to 24 mcg/kg/day are well tolerated in neonates ≥35 weeks' gestation treated for NAS. Any decreases in heart rate are likely clinically insignificant, and increases in blood pressure upon discontinuing clonidine are mild and may be mitigated further with extended discontinuation protocols. Further trials should be conducted to evaluate the long-term safety of clonidine in this population.

Rapid cardiovascular effects of dexamethasone in rabbits with meconium-induced acute lung injury

2008 ◽  
Vol 86 (11) ◽  
pp. 804-814 ◽  
Author(s):  
Daniela Mokra ◽  
Ingrid Tonhajzerova ◽  
Juraj Mokry ◽  
Anna Drgova ◽  
Maria Petraskova ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Side Effects ◽  
Rabbit Model ◽  
Intratracheal Instillation ◽  
Cardiovascular Effects ◽  
Meconium Aspiration Syndrome ◽  
Cardiovascular Side Effects ◽  
Acute Side Effects ◽  
Systemic Glucocorticoids

Glucocorticoids may improve lung function in newborns with meconium aspiration syndrome (MAS), but information on the acute side effects of glucocorticoids in infants is limited. In this study using a rabbit model of MAS, we addressed the hypothesis that systemic administration of dexamethasone causes acute cardiovascular changes. Adult rabbits were treated with 2 intravenous doses of dexamethasone (0.5 mg/kg each) or saline at 0.5 h and 2.5 h after intratracheal instillation of human meconium or saline. Animals were oxygen-ventilated for 5 h after the first dose of treatment. Blood pressure, heart rate, and short-term heart rate variability (HRV) were analyzed during treatment, for 5 min immediately after each dose, and for the 5 h of the experiment. In the meconium-instilled animals, dexamethasone increased blood pressure, decreased heart rate, increased HRV parameters, and caused cardiac arrhythmia during and immediately after administration. In the saline-instilled animals, the effect of dexamethasone was inconsistent. In these animals, the acute effects of dexamethasone on blood pressure and cardiac rhythm were reversed after 30 min, whereas heart rate continued to decrease and HRV parameters continued to increase for 5 h after the first dose of dexamethasone. These effects were more pronounced in meconium-instilled animals. If systemic glucocorticoids are used in the treatment of MAS, cardiovascular side effects of glucocorticoids should be considered.

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