Hemodynamic and sympathoadrenal responses to mental stress during nitric oxide synthesis inhibition

2004 ◽  
Vol 287 (5) ◽  
pp. H2309-H2315 ◽  
Author(s):  
Madeleine Lindqvist ◽  
Anders Melcher ◽  
Paul Hjemdahl

Cardiovascular and sympathoadrenal responses to a reproducible mental stress test were investigated in eight healthy young men before and during intravenous infusion of the nitric oxide (NO) synthesis inhibitor N-monomethyl-l-arginine (l-NMMA). Before l-NMMA, stress responses included significant increases in heart rate, mean arterial pressure, and cardiac output (CO) and decreases in systemic and forearm vascular resistance. Arterial plasma norepinephrine (NE) increased. At rest after 30 min of infusion of l-NMMA (0.3 mg·kg−1·min−1 iv), mean arterial pressure increased from 98 ± 4 to 108 ± 3 mmHg ( P < 0.001) because of an increase in systemic vascular resistance from 12.9 ± 0.5 to 18.5 ± 0.9 units ( P < 0.001). CO decreased from 7.7 ± 0.4 to 5.9 ± 0.3 l/min ( P < 0.01). Arterial plasma NE decreased from 2.08 ± 0.16 to 1.47 ± 0.14 nmol/l. Repeated mental stress during continued infusion of l-NMMA (0.15 mg·kg−1·min−1) induced qualitatively similar cardiovascular responses, but there was a marked attenuation of the increase in mean arterial blood pressure, resulting in similar “steady-state” blood pressures during mental stress without and with NO blockade. Increases in heart rate and CO were attenuated, but stress-induced decreases in systemic and forearm vascular resistance were essentially unchanged. Arterial plasma NE increased less than during the first stress test. Thus the increased arterial tone at rest during l-NMMA infusion is compensated for by attenuated increases in blood pressure during mental stress, mainly through a markedly attenuated CO response and suppressed sympathetic nerve activity.

1996 ◽  
Vol 270 (3) ◽  
pp. E393-E399 ◽  
Author(s):  
M. Lindqvist ◽  
T. Kahan ◽  
A. Melcher ◽  
P. Bie ◽  
P. Hjemdahl

The contribution of epinephrine (Epi) to forearm vasodilator responses to mental stress was evaluated in 12 healthy men by comparing hemodynamic and plasma catecholamine responses to mental stress and to intravenous and intra-arterial infusions of epinephrine. Mental stress decreased forearm vascular resistance (FVR) by 45%, increased arterial Epi from 0.23 to 0.44 nmol/l in arterial plasma, and increased forearm norepinephrine overflow. Intra-arterial Epi infusion decreased FVR concentration dependently by up to 43%. Intravenous Epi infusion decreased diastolic arterial pressure and increased heart rate and systolic blood pressure dose dependently. FVR decreased by up to 39% at 4.60 nmol/l Epi in arterial plasma. The average Epi contribution to forearm vasodilation during mental stress was calculated to be between 9 and 30%, depending on if responses to stress were compared with intravenous or intra-arterial Epi infusion. Arterial atrial natriuretic peptide immunoreactivity increased by 23% during stress, supporting a vasodilator influence, whereas vasopressin immunoreactivity was unaffected. Thus secretion of Epi explains only part of the stress-induced forearm vasodilation. Intravenous infusion of Epi appears to activate sympathetic counterregulation.


1998 ◽  
Vol 94 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Sharmini Puvi-Rajasingham ◽  
Gareth D. P. Smith ◽  
Adeola Akinola ◽  
Christopher J. Mathias

1. In human sympathetic denervation due to primary autonomic failure, food and exercise in combination may produce a cumulative blood pressure lowering effect due to simultaneous splanchnic and skeletal muscle dilatation unopposed by corrective cardiovascular reflexes. We studied 12 patients with autonomic failure during and after 9 min of supine exercise, when fasted and after a liquid meal. Standing blood pressure was also measured before and after exercise. 2. When fasted, blood pressure fell during exercise from 162 ± 7/92 ± 4 to 129 ± 9/70 ± 5 mmHg (mean arterial pressure by 22 ± 5%), P < 0.0005. After the meal, blood pressure fell from 159 ± 8/88 ± 6 to 129 ± 6/70 ± 4 mmHg (mean arterial pressure by 22 ± 3%), P < 0.0001, and further during exercise to 123 ± 6/61 ± 3 mmHg (mean arterial pressure by 9 ± 3%), P < 0.01. The stroke distance—heart rate product, an index of cardiac output, did not change after the meal. During exercise, changes in the stroke distance—heart rate product were greater when fasted. 3. Resting forearm and calf vascular resistance were higher when fasted. Calf vascular resistance fell further after exercise when fasted. Resting superior mesenteric artery vascular resistance was lower when fed; 0.19 ± 0.02 compared with 032 ± 0.06, P < 0.05. After exercise, superior mesenteric artery vascular resistance had risen by 82%, to 0.53 ± 0.12, P < 0.05 (fasted) and by 47%, to 0.29 ± 0.05, P < 0.05 (fed). 4. On standing, absolute levels of blood pressure were higher when fasted [83 ± 7/52 ± 7 compared with 71 ± 2/41 ± 3 (fed), each P < 0.05]. Subjects were more symptomatic on standing post-exercise when fed. 5. In human sympathetic denervation, exercise in the fed state lowered blood pressure further than when fasted and worsened symptoms of postural hypotension.


2001 ◽  
Vol 280 (5) ◽  
pp. R1462-R1468 ◽  
Author(s):  
Holly R. Middlekauff ◽  
Jun Liang Yu ◽  
Kakit Hui

In animal studies, acupuncture has been shown to be sympathoinhibitory, but it is unknown if acupuncture is sympathoinhibitory in humans. Nineteen healthy volunteers underwent mental stress testing pre- and postacupuncture. Muscle sympathetic nerve activity (MSNA), blood pressure, and heart rate during mental stress were compared pre- and postacupuncture. Control acupuncture consisted of acupuncture at nonacupoints and “no-needle” acupuncture. Acupuncture had no effect on resting MSNA, blood pressure, or heart rate. After real acupuncture, the increase in mean arterial pressure (pre- vs. postacupuncture 4.5 vs. 1.7 mmHg, P < 0.001), but not MSNA or heart rate, was blunted during mental stress. Similarly, following nonacupoint acupuncture, the increase in mean arterial pressure was blunted during mental stress (5.4 vs. 2.9 mmHg, P < 0.0003). No-needle acupuncture had no effect on these variables. In conclusion, acupuncture at traditional acupoints, nonacupoints, and no-needle acupuncture does not modulate baseline MSNA or MSNA responses to mental stress in normal humans. Acupuncture significantly attenuates the increase in blood pressure during mental stress. Needling nonacupoints, but not “no-needle” acupuncture, have a similar effect on blood pressure.


2016 ◽  
Vol 311 (4) ◽  
pp. R643-R648 ◽  
Author(s):  
Zachary J. Schlader ◽  
Gregory L. Coleman ◽  
James R. Sackett ◽  
Suman Sarker ◽  
Blair D. Johnson

We tested the hypothesis that increases in blood pressure are sustained throughout 15 min of face cooling. Two independent trials were carried out. In the Face-Cooling Trial, 10 healthy adults underwent 15 min of face cooling where a 2.5-liter bag of ice water (0 ± 0°C) was placed over their cheeks, eyes, and forehead. The Sham Trial was identical except that the temperature of the water was 34 ± 1°C. Primary dependent variables were forehead temperature, mean arterial pressure, and forearm vascular resistance. The square root of the mean of successive differences in R-R interval (RMSSD) provided an index of cardiac parasympathetic activity. In the Face Cooling Trial, forehead temperature fell from 34.1 ± 0.9°C at baseline to 12.9 ± 3.3°C at the end of face cooling ( P < 0.01). Mean arterial pressure increased from 83 ± 9 mmHg at baseline to 106 ± 13 mmHg at the end of face cooling ( P < 0.01). RMSSD increased from 61 ± 40 ms at baseline to 165 ± 97 ms during the first 2 min of face cooling ( P ≤ 0.05), but returned to baseline levels thereafter (65 ± 49 ms, P ≥ 0.46). Forearm vascular resistance increased from 18.3 ± 4.4 mmHg·ml−1·100 g tissue−1·min at baseline to 26.6 ± 4.0 mmHg·ml−1·100 g tissue−1·min at the end of face cooling ( P < 0.01). There were no changes in the Sham Trial. These data indicate that increases in blood pressure are sustained throughout 15 min of face cooling, and face cooling elicits differential time-dependent parasympathetic and likely sympathetic activation.


1988 ◽  
Vol 255 (6) ◽  
pp. H1443-H1451 ◽  
Author(s):  
U. Freyschuss ◽  
P. Hjemdahl ◽  
A. Juhlin-Dannfelt ◽  
B. Linde

Cardiovascular, sympathoadrenal, and subjective responses to mental stress induced by a color-word conflict test (CWT) were studied in 30 healthy males before and after intravenous administration of either placebo, beta 1-blockade by metoprolol (0.15 mg/kg), or nonselective beta-blockade by propranolol (0.15 mg/kg). CWT responses were reproducible. Mean arterial pressure increased by 20%. A mainly heart rate-dependent 65% increase in cardiac output (thermodilution) was associated with 25% decreases of both systemic (SVR) and calf vascular (CVR) resistances. Arterial plasma epinephrine (Epi) was doubled, and norepinephrine (NE) increased by 50%. Self-evaluated stress score correlated positively with changes in cardiac output and inversely with changes in SVR during CWT. Both metoprolol and propranolol halved heart rate responses; whereas increases in mean arterial pressure, Epi, and NE were uninfluenced. Metoprolol reduced the increase in stroke volume, and propranolol abolished it. SVR and CVR responses were attenuated by metoprolol and abolished by propranolol. The results suggest that mental stress accelerates the heart through neurogenic mechanisms and that peripheral vasodilatation is achieved through the concerted actions of reduced vasoconstrictor activity and elevated circulating Epi.


2002 ◽  
Vol 96 (5) ◽  
pp. 1086-1094 ◽  
Author(s):  
James M. Bailey ◽  
Wei Lu ◽  
Jerrold H. Levy ◽  
James G. Ramsay ◽  
Linda Shore-Lesserson ◽  
...  

Background Treatment of elevated blood pressure is frequently necessary after cardiac surgery to minimize postoperative bleeding and to attenuate afterload changes associated with hypertension. The purpose of this study was to investigate the pharmacodynamics and pharmacokinetics of a short-acting calcium channel antagonist, clevidipine, in the treatment of hypertension in postoperative cardiac surgical patients. Methods Postoperative cardiac surgical patients were randomized to receive placebo or one of six doses of clevidipine. Hemodynamic parameters were recorded and blood samples were drawn for determination of clevidipine plasma concentrations during infusion and after discontinuation of clevidipine. The concentration-response relation was analyzed using logistic regression, and pharmacokinetic models were applied to the data using population analysis. Results There were significant decreases in mean arterial blood pressure and systemic vascular resistance at doses greater than or equal to 1.37 microg. kg-1. min-1. There were no changes in heart rate, central venous pressure, pulmonary artery occlusion pressure, or cardiac index with increasing doses of clevidipine. The clevidipine C50 value for a 10% or greater decrease in mean arterial pressure was 9.7 microg/l and for a 20% or greater decrease in mean arterial pressure was 26.3 microg/l. The pharmacokinetics of clevidipine were best described with a three-compartment model with a volume of distribution of 32.4 l and clearance of 4.3 l/min. The early phase of drug disposition had a half-life of 0.6 min. The context-sensitive half-time is less than 2 min for up to 12 h of administration. Conclusion Clevidipine is a calcium channel antagonist with a very short duration of action that effectively decreases systemic vascular resistance and mean arterial pressure without changing heart rate, cardiac index, or cardiac filling pressures.


2008 ◽  
Vol 294 (1) ◽  
pp. H190-H197 ◽  
Author(s):  
Jill M. Wecht ◽  
Joseph P. Weir ◽  
David S. Goldstein ◽  
Annmarie Krothe-Petroff ◽  
Ann M. Spungen ◽  
...  

Direct effects of vasoactive substances on blood pressure can be examined in individuals with tetraplegia due to disruption of descending spinal pathways to sympathetic preganglionic neurons, as cervical lesions interfere with baroreceptor reflex buffering of sympathetic outflow. In this study, we assessed effects of the nitric oxide synthase inhibitor nitro-l-arginine methyl ester (l-NAME) on mean arterial pressure, heart rate, and plasma norepinephrine concentrations in individuals with tetraplegia vs. effects shown in a neurologically intact control group. Seven individuals with tetraplegia and seven age-matched controls received, on separate visits and in the following order, placebo (30 ml normal saline) and 0.5, 1, 2, and 4 mg/kg l-NAME intravenously over 60 min. Supine hemodynamic data were collected, and blood was sampled at the end of each infusion and at 120, 180, and 240 min thereafter. l-NAME increased mean arterial pressure, and the relative increase was greater in the tetraplegia group than in the control group. Heart rate was reduced after l-NAME administration in both groups. l-NAME decreased plasma norepinephrine in the control group but not in the group with tetraplegia. These findings suggest that reflexive sympathoinhibition normally buffers the pressor response to nitric oxide synthase inhibition, an effect that is not evident in individuals with tetraplegia as a result of decentralized sympathetic vasomotor control.


2014 ◽  
Vol 21 (2) ◽  
pp. 141
Author(s):  
Yanti Ivana Suryanto

Dalam praktek klinis kedokteran gigi, seringkali pasien datang dengan tekanan darah yang tinggi meskipun ia tidak memiliki riwayat hipertensi sebelumnya. Pada kondisi ini, tingginya tekanan darah seringkali dipengaruhi oleh tingkat kecemasan pasien yang nantinya akan mempengaruhi sistem saraf otonom. Akupunktur merupakan suatu metode pengobatan dengan penusukan jarum tanpa memasukkan bahan kimia ke dalam tubuh pasien. Penelitian ini bertujuan untuk mengkaji pengaruh penusukan tunggal titik akupunktur telinga Ciao Kan terhadap tekanan darah dan frekuensi denyut jantung. Hipotesis yang diajukan adalah penusukan tunggal titik akupunktur telinga Ciao Kan menyebabkan terjadinya penurunan tekanan darah dan frekuensi denyut jantung. Penelitian ini merupakan penelitian eksperimental dengan mempergunakan rancangan penelitian pre-post test design. Subjek penelitian adalah laki-laki berusia 25–35 tahun dengan tekanan sistolik lebih atau sama dengan 130 mmHg yang memenuhi kriteria inklusi dan eksklusi. Subjek menjalani orthostatic stress test, penusukan titik akupunktur telinga Ciao Kan, pengukuran tekanan darah dan frekuensi denyut jantung. Metode statistik yang dipergunakan adalah uji t, uji korelasi Pearson, dan uji ANOVA satu jalur. Uji t dilakukan pada data yang telah ditransformasi. Tekanan sistolik turun signifikan pada subyek penelitian selama perlakuan (p<0,05) namun kemudian naik kembali. Frekuensi denyut jantung juga mengalami penurunan signifikan (p<0,05) selama perlakuan dan naik kembali. Uji korelasi Pearson dilakukan untuk melihat korelasi antara tekanan arteri rata-rata dengan frekuensi denyut jantung. Hasil uji korelasi menunjukkan adanya korelasi positif antara tekanan arteri rata-rata dan frekuensi denyut jantung (r =0,373). Uji ANOVA satu jalur menunjukkan tidak adanya perbedaan nilai tekanan sistolik, tekanan diastolik, tekanan arteri rata-rata, dan frekuensi denyut jantung antar kelompok dengan respon terhadap orthostatic stress test normal, hipertonus, maupun hipotonus (p >0,05). Dengan demikian dapat dikatakan bahwa penusukan tunggal titik akupunktur telinga Ciao Kan menyebabkan terjadinya penurunan tekanan darah dan frekuensi denyut jantung. The Effect of Single Acupuncture on Ciao Kan Ear Acupoint on Blood Pressure and Heart Rate In dental clinical practice. Patient sometime come with high blood pressure even though they have no history of hypertension. In this condition, high blood pressure could be influenced by anxiety that will have an effect on autonomic nerve system. Acupuncture is a healing method with needle puncture without giving chemical substance to patient’s body. This research aimed at evaluating the effect of a single acupuncture on Ciao Kan ear acupoint on blood pressure and heart rate. Hypothesis of this research was single acupuncture on Ciao Kan ear acupoint could decrease blood pressure and heart rate. This was a pre-post test design experiment. Subjects were men, 25 – 35 years old with systolic blood pressure equal or more than 130 mmHg who met the inclusion and exclusion criteria. Subject did orthostatic stress test, acupuncture on Ciao Kan ear acupoint, blood pressure measurement, and heart rate measurement. T test was done on the transformed data. Systolic blood pressure decreased significantly (p < 0.05) during acupuncture and then increased afterward. Heart rates also decreased significantly (p < 0.05) during acupuncture and then increased afterward. Pearson correlation test was done to see the correlation between mean arterial pressure and heart rate. The results showed a positive correlation between mean arterial pressure and heart rate (r = 0.373). One way ANOVA showed no systolic, diastolic, mean arterial pressure, and heart rate differences between groups in response to orthostatic stress test normal, hyper tone, or hypo tone (p > 0.05). It could be said that single acupuncture on Ciao Kan ear acupoint could decrease blood pressure and heart rate.


2002 ◽  
Vol 93 (6) ◽  
pp. 1966-1972 ◽  
Author(s):  
Maria T. E. Hopman ◽  
Jan T. Groothuis ◽  
Marcel Flendrie ◽  
Karin H. L. Gerrits ◽  
Sibrand Houtman

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.


Author(s):  
Sidharth Sraban Routray ◽  
Ramakanta Mohanty

ABSTRACTObjective: During laparoscopic surgeries, pneumoperitoneum can lead to various pathophysiologic changes in the cardiovascular system resulting inhypertension and tachycardia. Search for ideal drug to prevent this hemodynamic response goes on. The aim of our study was to evaluate the effect oforally administered moxonidine in attenuating the hemodynamic responses that occur during the laparoscopic surgeries.Methods: A total of 50 adult acetylsalicylic acid I and II patients scheduled for elective laparoscopic surgeries were selected for this prospectiverandomized double-blinded study. They were randomly allocated into two groups: moxonidine group (M) and placebo group (P). M group receivedoral moxonidine 0.3 mg at 8 pm on the day before surgery and at 8 am on the day of surgery. P group received a placebo at the same timing as that ofthe M group.Results: Following pneumoperitoneum rise in systolic blood pressure (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and heart rate (HR)was higher in P group in comparison to M group which was statistically significant.Conclusion: Significant rise in HR, SBP, DBP, and mean BP was noted in the P group in comparison to moxonidine group. Moxonidine provided betterperioperative hemodynamic stability in patients undergoing laparoscopic surgeries.Keywords: Moxonidine, Stress response, Laparoscopic.


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