Cardiovascular responses to hemorrhage and naloxone in conscious barodenervated rabbits

1986 ◽  
Vol 251 (5) ◽  
pp. R909-R915 ◽  
Author(s):  
J. C. Schadt ◽  
R. R. Gaddis
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Loss ◽  
Vascular Resistance ◽  
Mean Arterial Blood Pressure ◽  
Plasma Norepinephrine ◽  
Receptor Blockade ◽  
Pressor Effect ◽  
Arterial Blood ◽  
Before And After

The hemodynamic and plasma catecholamine response to hypotensive hemorrhage and subsequent opioid receptor blockade with naloxone were evaluated before and after complete sinoaortic denervation (SAD). This study was done to test the general hypothesis that opioid-mediated failure of the baroreflex accounts for the hypotension of hemorrhage. The specific hypothesis we tested was that SAD would abolish the pressor effect of opioid receptor blockade with naloxone. The studies were done in conscious chronically prepared rabbits. Hemorrhage of 12 ml/kg did not change mean arterial blood pressure in intact animals due to a compensatory increase in heart rate and vascular resistance. When blood loss exceeded 12 ml/kg, pressure decreased abruptly due to a decrease in vascular resistance. Plasma norepinephrine (NE) and epinephrine (E) were higher after hemorrhage than before. Plasma E levels increased almost 70 times. After SAD, mean blood pressure began to decrease at the beginning of hemorrhage, the heart rate increase was abolished, and vascular resistance decreased throughout the blood loss. Plasma NE was no different after hemorrhage than before. Plasma E increased, but the increase was only fivefold. Naloxone increased mean arterial blood pressure, vascular resistance, cardiac index, and plasma NE before and after SAD. The increases in blood pressure and plasma norepinephrine were significantly greater after SAD. Therefore the pressor effect of naloxone in this model is not due to increased baroreflex sensitivity. Rather, intact baroreflexes buffer naloxone's effects.

Patterned cardiovascular responses to sleep and nonrespiratory arousals in a porcine model

1998 ◽  
Vol 85 (4) ◽  
pp. 1285-1291 ◽  
Author(s):  
Sandrine H. Launois ◽  
Joseph H. Abraham ◽  
J. Woodrow Weiss ◽  
Debra A. Kirby
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Eye Movement ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Mean Arterial Blood Pressure ◽  
Rapid Eye Movement ◽  
Rapid Eye Movement Sleep ◽  
Arterial Blood

Patients with obstructive sleep apnea experience marked cardiovascular changes with apnea termination. Based on this observation, we hypothesized that sudden sleep disruption is accompanied by a specific, patterned hemodynamic response, similar to the cardiovascular defense reaction. To test this hypothesis, we recorded mean arterial blood pressure, heart rate, iliac blood flow and vascular resistance, and renal blood flow and vascular resistance in five pigs instrumented with chronic sleep electrodes. Cardiovascular parameters were recorded during quiet wakefulness, during non-rapid-eye-movement and rapid-eye-movement sleep, and during spontaneous and induced arousals. Iliac vasodilation (iliac vascular resistance decreased by −29.6 ± 4.1% of baseline) associated with renal vasoconstriction (renal vascular resistance increased by 10.3 ± 4.0%), tachycardia (heart rate increase: +23.8 ± 3.1%), and minimal changes in mean arterial blood pressure were the most common pattern of arousal response, but other hemodynamic patterns were observed. Similar findings were obtained in rapid-eye-movement sleep and for acoustic and tactile arousals. In conclusion, spontaneous and induced arousals from sleep may be associated with simultaneous visceral vasoconstriction and hindlimb vasodilation, but the response is variable.

Heart rate and blood pressure effects during caloric vestibular testing

2010 ◽  
Vol 124 (6) ◽  
pp. 616-622 ◽  
Author(s):  
A V Kasbekar ◽  
D M Baguley ◽  
R Knight ◽  
P Gomersall ◽  
R Parker ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Phase Velocity ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Pressure Effects ◽  
Slow Phase ◽  
Slow Phase Velocity ◽  
Arterial Blood ◽  
Before And After

AbstractObjectives:To determine whether the caloric vestibular test causes significant changes in heart rate and mean arterial blood pressure.Materials and methods:Changes in heart rate and mean arterial blood pressure before and after caloric irrigation were compared with the degree of nystagmus (as measured by maximum slow phase velocity) and the patient's subjective dizziness (scored from 0 to 10). A cardiologist reviewed each patient's heart rate and mean arterial blood pressure changes. Patients' anxiety levels were also assessed.Results:Eighteen patients were recruited. There were no adverse events in any patient. There were no overall significant differences between the heart rate and mean arterial pressure before and after each irrigation. There was a significant correlation between the maximum slow phase velocity and patients' subjective dizziness scores.Conclusion:Heart rate and mean arterial blood pressure are not significantly influenced by the caloric vestibular test. This preliminary study will enable patients with stable cardiovascular disease to be recruited for further risk determination.

Central and regional hemodynamic effects during infusion of Big endothelin-1 in healthy humans

1996 ◽  
Vol 80 (6) ◽  
pp. 1921-1927 ◽  
Author(s):  
G. Ahlborg ◽  
A. Ottosson-Seeberger ◽  
A. Hemsen ◽  
J. M. Lundberg
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Systemic Vascular Resistance ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Mean Arterial Blood Pressure ◽  
Endothelin 1 ◽  
Healthy Humans ◽  
Arterial Blood

Big endothelin-1 (Big ET-1) was given intravenously to six healthy men to study uptakes and vascular effects. Blood samples were taken from systemic and pulmonary arterial and internal jugular and deep forearm venous catheters. Arterial Big ET-1-like immunoreactivity (Big ET-1-LI) increased from 5.43 +/- 0.60 to 756 +/- 27 pmol/l, and ET-1-LI increased from 4.67 +/- 0.08 to 6.67 +/- 0.52 pmol/l (P < 0.001). Skeletal muscle fractional extraction of Big ET-1-LI was 15 +/- 4%. ET-1-LI release did not increase in the studied vascular beds. Heart rate fell by 17% (P < 0.001), cardiac output fell by 26% (P < 0.001), and stroke volume fell by 11% (P < 0.05). Mean arterial blood pressure increased 18%, systemic vascular resistance increased 65%, and pulmonary vascular resistance increased 57% (P < 0.01-0.001). Pulmonary blood pressures, forearm blood flow, arterial pH, arterial PCO2, and systemic arterial-internal jugular venous O2 difference remained unchanged. No specific Big ET-1 receptors were found in human pulmonary membranes. The half-maximal inhibitory concentration for the receptor antagonist bosentan was 181 nM. In summary, circulating Big ET-1 elicits greater increases in mean arterial blood pressure and systemic vascular resistance and decreases in heart rate and cardiac output compared with an equimolar ET-1 infusion (26).

scholarly journals Comparison of intraocular pressure, tear production and cardiorespiratory variables before and after induction of anaesthesia with either propofol or ketofol in dogs premedicated with midazolam

2018 ◽  
Vol 63 (No. 6) ◽  
pp. 271-278
Author(s):  
H. Imani Rastabi ◽  
A. Baniadam ◽  
A. Ronagh ◽  
A. Khajeh ◽  
M. Kamyabnia
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Intraocular Pressure ◽  
Respiratory Depression ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Arterial Blood ◽  
Tear Production ◽  
Before And After ◽  
Induction Of Anaesthesia

The objective of the present study was to compare the effects of propofol and ketofol on intraocular pressure, tear production and cardiorespiratory variables in dogs premedicated with midazolam. Six castrated adult mixed-breed dogs were used in a cross-over design with a one-week interval. Twenty minutes after premedication with midazolam (0.2 mg/kg), animals were assigned randomly to two groups and received either propofol (6 mg/kg) or ketofol (3 mg/kg; 1 : 1 mg/ml ratio) treatments intravenously. Intraocular pressure, tear production, heart rate, respiratory rate, rectal temperature and direct mean arterial blood pressure were measured at base (before induction), and at 5, 10, 15, 20 and 30 min after induction of anaesthesia. Blood gas samples were obtained at base (before induction), and at 5, 15 and 30 min after administration of treatments. Intraocular pressure showed significantly higher values at 5 min after induction in ketofol compared with propofol (16.1 ± 4.5 mm Hg vs 8.2 ± 1.2 mm Hg, respectively). There were no significant changes in tear production in either group. Significantly higher heart rate and mean arterial blood pressure were detected in ketofol at several time points. Respiratory depression occurred in both groups with no significant differences between them. In conclusion, although ketofol improved heart rate and mean arterial blood pressure and did not elicit more pronounced respiratory depression than propofol, it resulted in significantly higher values of intraocular pressure at 5 min after administration in dogs. Despite the small number of dogs in this study, our results indicate that ketofol should not be recommended for ophthalmic surgical procedures in dogs. Appropriate oxygenation should be provided when propofol is used for ophthalmic surgeries.

Acute Haemodynamic and Hormonal Effects of Captopril are Diminished by Indomethacin

1982 ◽  
Vol 62 (6) ◽  
pp. 611-615 ◽  
Author(s):  
H. Witzgall ◽  
F. Hirsch ◽  
B. Scherer ◽  
P. C. Weber
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Plasma Renin ◽  
Hormonal Effects ◽  
Arterial Blood ◽  
Before And After ◽  
Pre Treatment ◽  
Excretion Rates

1. The acute haemodynamic and hormonal effects of 100 mg of captopril (SQ 14.225) orally were tested in twelve healthy men in the sodium replete state before and after indomethacin pre-treatment. 2. Without indomethacin, mean arterial blood pressure was reduced at 30 and 60 min after captopril (P < 0.02). Heart rate did not change during the whole experiment. Although plasma renin activity (PRA) increased (P < 0.002), plasma and urinary aldosterone and plasma 18-hydroxycorticosterone (18-OH-B) decreased after captopril (P < 0.02). Prostaglandin (PG) E2, sodium and potassium excretion rates remained constant after captopril. 3. Under indomethacin pretreatment, the fall in mean arterial blood pressure was less than without indomethacin at 30 and 60 min after captopril (P < 0.05). Heart rate was constantly lower than without indomethacin during the whole experiment (P < 0.05). Indomethacin pretreatment decreased basal PGE2 excretion (P < 0.02) and baseline PRA as well as the increase in PRA after captopril (P < 0.05). Control mineralocorticoid levels were significantly lower than without indomethacin. In indomethacin-pretreated subjects, aldosterone did not further decrease after captopril, and 18-OH-B fell only slightly. 4. Without indomethacin pretreatment a significant, positive correlation was found between PRA values before captopril and the maximum decrease of mean arterial blood pressure after captopril. Under indomethacin pretreatment this correlation was no longer demonstrable. The results suggest that prostaglandins may contribute to the haemodynamic and hormonal actions of captopril.

Changes in cardiac output and vascular resistance during behavioral stress in the rat

1986 ◽  
Vol 251 (1) ◽  
pp. R82-R90 ◽  
Author(s):  
J. W. Hubbard ◽  
R. H. Cox ◽  
B. J. Sanders ◽  
J. E. Lawler
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Mean Arterial Blood Pressure ◽  
Cardiovascular Response ◽  
Plasma Norepinephrine ◽  
Wky Rats ◽  
Arterial Blood ◽  
Behavioral Stress

Normotensive Wistar-Kyoto (WKY) rats and borderline hypertensive rats (BHR) were exposed to aversive classical conditioning procedures and chronically instrumented with arterial catheters and electromagnetic flow probes around the ascending aorta. After postoperative recovery, hemodynamic measurements and blood samples were obtained from conscious animals at rest and during aversive conditioning. The cardiovascular response to the behavioral stress consisted of a significant increase in mean arterial blood pressure, total peripheral resistance index, cardiac index, heart rate, and aortic dP/dt for both strains. However, the elevated vascular resistance seen in the BHR resulted in a significantly greater increase in mean arterial blood pressure (21 mmHg) compared with the WKY rats (14 mmHg). In addition, the BHR showed a significantly (P less than 0.05) greater plasma norepinephrine concentration (760 +/- 99 pg/ml) in response to the stress than did the WKY rats (559 +/- 53 pg/ml). These data suggest that an increase in cardiac output, elevated vascular resistance, and increased sympathetic drive may contribute to the development of stress-induced hypertension in this animal model.

Responses to GABA-A receptor blockade in the hypothalamic PVN are attenuated by local AT1 receptor antagonism

2003 ◽  
Vol 285 (5) ◽  
pp. R1231-R1239 ◽  
Author(s):  
Qing Hui Chen ◽  
Glenn M. Toney
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Sympathetic Nerve Activity ◽  
Neuronal Excitability ◽  
Receptor Blockade ◽  
Ang Ii ◽  
Nerve Activity ◽  
Gaba A ◽  
Arterial Blood ◽  
Before And After

Blockade of GABA-A receptors in the hypothalamic paraventricular nucleus (PVN) has been repeatedly shown to increase arterial blood pressure (ABP), heart rate (HR), and sympathetic nerve activity (SNA), but the mechanism(s) that underlies this response has not been determined. Here, we tested whether full expression of the response requires activation of local ANG II AT1 receptors. ABP, HR, and renal SNA responses to PVN microinjection of bicuculline methobromide (BIC; 0.1 nmol) were recorded before and after microinjection of vehicle (saline); losartan (or L-158809), to block local AT1 receptors; or PD123319 , to block AT2 receptors. After PVN microinjection of vehicle or PD123319 (10 nmol), BIC significantly ( P < 0.05) increased mean arterial pressure (MAP), HR, and renal SNA. However, PVN microinjection of 2 and 20 nmol of losartan dose dependently reduced responses to PVN-injected BIC, with the 20-nmol dose nearly abolishing MAP ( P < 0.005), HR ( P < 0.05), and renal SNA ( P < 0.005) responses. Another AT1 receptor antagonist, L-158809 (10 nmol), produced similar effects. Neither losartan nor L-158809 altered baseline parameters. Responses to PVN injection of BIC were unchanged by losartan (20 nmol) given intravenously or into the PVN on the opposite side. MAP, HR, and renal SNA responses to PVN microinjection of l-glutamate (10 nmol) were unaffected by PVN injection of losartan (20 nmol), indicating that effects of losartan were not due to nonspecific depression of neuronal excitability. We conclude that pressor, tachycardic, and renal sympathoexcitatory responses to acute blockade of GABA-A receptors in the PVN depend on activation of local AT1 receptors.

Comparative study on effect of neutral spinal bath and neutral spinal spray on blood pressure, heart rate and heart rate variability in healthy volunteers

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Arundhati Goley ◽  
A. Mooventhan ◽  
NK. Manjunath
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Volunteers ◽  
Group Analysis ◽  
Low Frequency ◽  
Single Session ◽  
Arterial Blood ◽  
Before And After ◽  
Instantaneous Heart Rate

Abstract Background Hydrotherapeutic applications to the head and spine have shown to improve cardiovascular and autonomic functions. There is lack of study reporting the effect of either neutral spinal bath (NSB) or neutral spinal spray (NSS). Hence, the present study was conducted to evaluate and compare the effects of both NSB and NSS in healthy volunteers. Methods Thirty healthy subjects were recruited and randomized into either neutral spinal bath group (NSBG) or neutral spinal spray group (NSSG). A single session of NSB, NSS was given for 15 min to the NSBG and NSSG, respectively. Assessments were taken before and after the interventions. Results Results of this study showed a significant reduction in low-frequency (LF) to high-frequency (HF) (LF/HF) ratio of heart rate variability (HRV) spectrum in NSBG compared with NSSG (p=0.026). Within-group analysis of both NSBG and NSSG showed a significant increase in the mean of the intervals between adjacent QRS complexes or the instantaneous heart rate (HR) (RRI) (p=0.002; p=0.009, respectively), along with a significant reduction in HR (p=0.002; p=0.004, respectively). But, a significant reduction in systolic blood pressure (SBP) (p=0.037) and pulse pressure (PP) (p=0.017) was observed in NSSG, while a significant reduction in diastolic blood pressure (DBP) (p=0.008), mean arterial blood pressure (MAP) (p=0.008) and LF/HF ratio (p=0.041) was observed in NSBG. Conclusion Results of the study suggest that 15 min of both NSB and NSS might be effective in reducing HR and improving HRV. However, NSS is particularly effective in reducing SBP and PP, while NSB is particularly effective in reducing DBP and MAP along with improving sympathovagal balance in healthy volunteers.

The Study of Dynamic Response to Acute Hemorrhage by Pulse Spectrum Analysis

2006 ◽  
Vol 34 (03) ◽  
pp. 449-460 ◽  
Author(s):  
Yu Hsin Chang ◽  
Chia I Tsai ◽  
Jaung Geng Lin ◽  
Yue Der Lin ◽  
Tsai Chung Li ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Steady State ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Spectrum Analysis ◽  
Pulse Spectrum ◽  
Acute Hemorrhage ◽  
Arterial Blood ◽  
Percentage Difference ◽  
Before And After

Traditional Chinese Medicine (TCM) holds that Blood and Qi are fundamental substances in the human body for sustaining normal vital activity. The theory of Qi, Blood and Zang-Fu contribute the most important theoretical basis of human physiology in TCM. An animal model using conscious rats was employed in this study to further comprehend how organisms survive during acute hemorrhage by maintaining the functionalities of Qi and Blood through dynamically regulating visceral physiological conditions. Pulse waves of arterial blood pressure before and after the hemorrhage were taken in parallel to pulse spectrum analysis. Percentage differences of mean arterial blood pressure and harmonics were recorded in subsequent 5-minute intervals following the hemorrhage. Data were analyzed using a one-way analysis of variance (ANOVA) with Duncan's test for pairwise comparisons. Results showed that, within 30 minutes following the onset of acute hemorrhage,the reduction of mean arterial blood pressure was improved from 62% to 20%. Throughout the process, changes to the pulse spectrum appeared to result in a new balance over time. The percentage differences of the second and third harmonics, which were related to kidney and spleen, both increased significantly than baseline and towards another steady state. Apart from the steady state resulting from the previous stage, the percentage difference of the 4th harmonic decreased significantly to another steady state. The observed change could be attributed to the induction of functional Qi, and is a result of Qi-Blood balancing activity that organisms hold to survive against acute bleeding.

Blood pressure during routine activity, stress, and feeding in black racer snakes (Coluber constrictor)

1993 ◽  
Vol 264 (1) ◽  
pp. R79-R84 ◽  
Author(s):  
J. N. Stinner ◽  
D. L. Ely
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Acute Stress ◽  
Pressor Response ◽  
Routine Activity ◽  
Plasma Norepinephrine ◽  
Arterial Blood ◽  
Coluber Constrictor ◽  
S Peak ◽  
Hematological Changes

The pressor response to normal daily behaviors and acute stress was studied in black racer snakes (Coluber constrictor) at 30 degrees C. In addition, hematological changes during the stress response were assessed. Mean nighttime systemic arterial blood pressure (SABP) in undisturbed snakes was lower than daytime pressure (26 +/- 3 vs. 32 +/- 9 mmHg, P < 0.001). When snakes were fed mice, SABP increased 3.5- to 4-fold and heart rate increased approximately 3-fold above resting values within approximately 30 s (peak SABP, 99 +/- 18 mmHg; peak heart rate, 99 +/- 12 beats/min). Killing and ingesting the mice required 6-15 min, during which time mean SABP and heart rate were 84 +/- 16 mmHg and 92 +/- 12 beats/min. Pulmonary blood pressure also increased but remained 40-50 mmHg lower than SABP. During stress elicited by tapping the snakes for 5-8 min, heart rate was 94 +/- 6 beats/min but SABP averaged only 44 +/- 11 mmHg. Plasma norepinephrine and epinephrine increased 51- and 26-fold. Plasma glucose increased 58%, hematocrit increased 19%, and plasma volume decreased 19%. It is concluded that blood pressure is markedly affected by behavior and that the sympathetic nervous system appears to play a key role.

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