Responses of the Systemic Circulation and of the Renin—Angiotensin—Aldosterone System to Ketanserin at Rest and Exercise in Normal Man

1984 ◽  
Vol 66 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Robert Fagard ◽  
Anne Cattaert ◽  
Paul Lijnen ◽  
Jan Staessen ◽  
Luc Vanhees ◽  
...  
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Catecholamines ◽  
Plasma Renin ◽  
Systemic Circulation ◽  
Work Rate ◽  
Plasma Aldosterone ◽  
Sitting Position ◽  
The Mean

1. The systemic circulation at rest and during exercise was studied in ten normal male volunteers, after placebo on one occasion and after acute intravenous administration of the serotonergic antagonist ketanserin on another occasion. The effects of ketanserin on the components of the renin—angiotensin—aldosterone system, on plasma catecholamines and on exercise capacity for graded uninterrupted exercise were also investigated. 2. At rest in recumbency rapid intravenous injection of 10 mg of ketanserin, followed by a continuous infusion of 2 mg/h, produced an acute but transient fall in mean intra-arterial pressure of 6 mmHg compared with placebo. After 15 min the mean arterial pressure with ketanserin was within 2 mmHg of the mean pressure with placebo. In the sitting position both at rest and up to 30% of maximal work rate, the mean arterial pressure during ketanserin did not differ from the pressure on placebo. However, at higher levels of physical activity the rise in mean arterial pressure was lower with ketanserin; the pressure achieved with placebo was 7.5 mmHg higher at maximal work rate. Heart rate and cardiac output were significantly higher during ketanserin. 3. When the subjects were lying down and resting, plasma noradrenaline and adrenaline levels, plasma renin activity and angiotensin II concentration were not affected by ketanserin; however, these values were higher in the sitting position both at rest and during exercise. Plasma aldosterone was reduced by ketanserin during exercise and also when the subject was resting in the recumbent position. 4. Exercise capacity as measured by peak oxygen uptake was similar during ketanserin (3.09 ± se 0.12 litres/min) and during placebo (3.11 ± 0.13). 5. The data suggest that 5-hydroxytryptamine can have only a small role, if any, in pressure homoeostasis in sodium replete man at rest in recumbency. At moderate and heavy levels of exercise, the results are compatible with a role for 5-hydroxytryptamine in pressure regulation. Activation of the sympathetic nervous system by ketanserin is suggested by increases of plasma catecholamines, heart rate, cardiac output and plasma renin. The suppression of plasma aldosterone suggests that 5-hydroxytryptamine may have a role in the regulation of aldosterone secretion which is independent of angiotensin II.

Renal Denervation Prevents Sodium Retention and Hypertension in Salt-Sensitive Rabbits with Genetic Baroreflex Impairment

1996 ◽  
Vol 90 (4) ◽  
pp. 287-293 ◽  
Author(s):  
Marta Weinstock ◽  
Elena Gorodetsky ◽  
Ronald Kalman
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Renin Activity ◽  
Renal Denervation ◽  
Plasma Renin ◽  
High Salt ◽  
Renin Activity ◽  
Group I ◽  
Group Ii

1. Rabbits with a genetic impairment in baroreflex control of heart rate become hypertensive on a high salt diet. The present study determined the effect of bilateral renal denervation on blood pressure and sodium balance after salt loading (four times normal intake; 28–36 mEq NaCl/day) in normotensive rabbits with high (Group I) and low (Group II) baroreflex sensitivity, respectively. 2. Eight rabbits in each group were denervated or sham-denervated 1 week before commencement of the high salt diet. Before operation, the two groups differed only in the gain of their cardiac baroreflex (Group I, −6.4 ± 0.4 beats min−1 mmHg−1; Group II, −3.2 ± 0.15 beats min−1 mmHg−1). 3. In Group I sham-denervated rabbits, mean arterial pressure remained unchanged, and plasma renin activity and heart rate fell significantly in response to the high salt. In Group II sham-denervated rabbits, mean arterial pressure increased by 10.6 ± 1.2 mmHg, and heart rate and plasma renin activity remained unchanged. Their cumulative Na+ retention and weight gain was more than twice that of Group I sham-denervated rabbits. 4. Renal denervation decreased plasma renin activity in both groups to <1 pmol Ang I h−1 ml−1, lowered cumulative Na+ retention from 102 ± 4 to 35 ± 5 mEq (P<0.01) and completely prevented the increase in mean arterial pressure in response to high salt in Group II. 5. The results suggest that Group II rabbits retain salt and fluid in response to their diet because of an abnormality in their control of renal nerve activity, possibly via vagal afferents. This results in blood pressure elevation because of an inability to lower peripheral resistance and heart rate in response to the increase in cardiac output. 6. Since they display several of the characteristics of salt-sensitive hypertensive humans, i.e. salt retention, normal plasma renin activity, but abnormal regulation of plasma renin activity and blood flow in response to salt loading, Group II are an appropriate model of human salt-induced hypertension.

Role of vasopressin in blood pressure regulation in conscious water-deprived dogs

1983 ◽  
Vol 244 (1) ◽  
pp. R74-R77 ◽  
Author(s):  
J. Schwartz ◽  
I. A. Reid
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Renin Activity ◽  
Water Deprivation ◽  
Plasma Renin ◽  
Renin Activity ◽  
Pressure Regulation

The role of vasopressin in the regulation of blood pressure during water deprivation was assessed in conscious dogs with two antagonists of the vasoconstrictor activity of vasopressin. In water-replete dogs, vasopressin blockade caused no significant changes in mean arterial pressure, heart rate, plasma renin activity (PRA), or plasma corticosteroid concentration. In the same dogs following 48-h water deprivation, vasopressin blockade increased heart rate from 85 +/- 6 to 134 +/- 15 beats/min (P less than 0.0001), increased cardiac output from 2.0 +/- 0.1 to 3.1 +/- 0.1 1/min (P less than 0.005), and decreased total peripheral resistance from 46.6 +/- 3.1 to 26.9 +/- 3.1 U (P less than 0.001). Plasma renin activity increased from 12.4 +/- 2.2 to 25.9 +/- 3.4 ng ANG I X ml-1 X 3 h-1 (P less than 0.0001) and plasma corticosteroid concentration increased from 3.2 +/- 0.7 to 4.9 +/- 1.2 micrograms/dl (P less than 0.05). Mean arterial pressure did not change significantly. When the same dogs were again deprived of water and pretreated with the beta-adrenoceptor antagonist propranolol, the heart rate and PRA responses to the antagonists were attenuated and mean arterial pressure decreased from 103 +/- 2 to 91 +/- 3 mmHg (P less than 0.001). These data demonstrate that vasopressin plays an important role in blood pressure regulation during water deprivation in conscious dogs.

scholarly journals COMPARATIVE CHARACTERISTICS OF THE DYNAMICS OF CARDIOVASCULAR AND RESPIRATORY EFFECTS OF PNEUMOPERITONEUM BASED ON CARBON DIOXIDE AND ARGON IN LAPAROSCOPIC CHOLECYSTECTOMY

2021 ◽  
pp. 90-95
Author(s):  
O. L. Tkachuk ◽  
R. L. Parakhoniak ◽  
S. V. Melnyk ◽  
O. O. Tkachuk-Hryhorchuk
Keyword(s):  
Carbon Dioxide ◽  
Heart Rate ◽  
Cardiac Output ◽  
Laparoscopic Cholecystectomy ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Negative Impact ◽  
Abdominal Pressure ◽  
The Mean ◽  
Respiratory Systems

Pneumoperitoneum is one of the most critical components of laparoscopic surgery, which has a negative effect on gas exchange and stress to circulatory buffering system. One of the top priorities of laparoscopic technologies is to minimize the impact on the respiratory and cardiovascular systems, metabolic dynamics and compensatory abilities of homeostasis. The main goal of this research work is to compare the effects of carboxyperitoneum and argonoperitoneum on the intraoperative dynamics of CO2 concentration as well as cardiovascular and respiratory characteristics in patients undergoing laparoscopic cholecystectomy for various forms of cholelithiasis. Materials and methods. Four experimental groups involved patients based on their nosological form of cholelithiasis and the gas used to induce pneumoperitoneum. All patients underwent laparoscopic cholecystectomy by means of standard procedure. Either medical carbon dioxide or medical argon was used to induce pneumoperitoneum. Intraoperative monitoring of blood carbon dioxide levels PaCO2 was performed by taking venous blood every 15 minutes. Capnometry was performed by means of mainstream analysis using “BIOMED” BM1000C modular patient monitor by recording the discrete values of PetCO2 every 15 minutes, as well as by analyzing photocopies of capnography curves every 15 minutes. Intraoperative echocardiography was performed to identify the mean arterial pressure (MAP), heart rate (HR) and cardiac output (CO) in order to assess the effects of different types of pneumoperitoneum on the cardiovascular system. Results. The obtained data confirm the expected difference in the indices of cardiorespiratory functions between patients with acute cholecystitis and cholelithiasis without signs of inflammation. The investigation revealed that under the influence of pneumoperitoneum, heart rate and mean arterial pressure increase, while the cardiac output decreases. The respiratory pressure marker depends more on the intra-abdominal pressure and presumably the patient’s body type than on the presence of inflammatory syndrome. Argon insufflation has a slight negative impact on the cardiovascular system. Particularly, the mean arterial pressure and heart rate increase, while the cardiac output marker is less decreased as compared to the use of carbon dioxide. Abdominal pressure has a significant effect on the cardiovascular and respiratory systems regardless of the used type of gas. The combination of high intra-abdominal pressure with the elevated head end of the operating table, which is a common practise during cholecystectomy, has especially great influence on cardiovascular and respiratory functions. Operation which is carried out at decreased pressure allows reducing the deviations of practically all indices. Conclusions. Thus, the cardiovascular and respiratory systems adapt under the influence of pneumoperitoneum, providing compensation for the negative effects of mechanical and resorptive-metabolic character. Compensatory-adaptive abilities of the cardiovascular and respiratory systems increase with the decrease of intra-abdominal pressure. The use of argon as a working gas for insufflation into the abdominal cavity during laparoscopy reduces the negative impact of pneumoperitoneum on the cardiovascular and respiratory systems, providing a greater reserve of homeostatic and buffer systems of the body.

Hemodynamic effects of neurohypophyseal peptides with antidiuretic activity in dogs

1985 ◽  
Vol 249 (5) ◽  
pp. H1001-H1008 ◽  
Author(s):  
J. Schwartz ◽  
J. F. Liard ◽  
C. Ott ◽  
A. W. Cowley
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Renin Activity ◽  
Peripheral Resistance ◽  
Cardiovascular Effects ◽  
Plasma Renin ◽  
Hemodynamic Effects ◽  
Antidiuretic Activity

Arginine vasopressin (AVP) is known to produce increases in total peripheral resistance (TPR) and mean arterial pressure (MAP) and decreases in heart rate (HR), cardiac output (CO), and plasma renin activity (PRA). Some recent observations with AVP and synthetic analogues have suggested that under certain conditions, AVP can induce cardiovascular and reninsecretory responses in the opposite directions. To characterize the receptors mediating these responses, the effects of AVP, oxytocin, and synthetic neurohypophyseal analogues with specific antidiuretic, vasoconstrictor, or oxytocic activities were studied in conscious dogs. AVP and 2-phenylalanine-8-ornithine-oxytocin (Phe2Orn8OT, a selective vasoconstrictor agonist) produced similar responses when infused at 10 ng X kg-1 X min-1. That is, TPR and MAP increased, and CO, HR, and PRA decreased. Pretreatment with a selective vasoconstrictor antagonist, [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid) 2-(O-methyl)tyrosine]AVP, abbreviated d(CH2)5Tyr(Me)-AVP (10 micrograms/kg), blocked the actions of Phe2Orn8OT. However, in the presence of d(CH2)5Tyr(Me)AVP, AVP actually decreased TPR and increased CO, HR, and PRA. An analogue with selective antidiuretic activity, 4-valine-8-D-AVP (VDAVP, 10 ng X kg-1 X min-1), produced the same effects as the combination of vasopressin plus d(CH2)5Tyr(Me)AVP. Neither the effects of VDAVP nor of AVP plus antagonist were blocked by propranolol (1 mg/kg). These data indicate that vasopressin, by its antidiuretic activity, produces cardiovascular effects that are opposite to many of those produced by its vasoconstrictor action and that these effects are not dependent on mediation by beta-adrenoceptors.

scholarly journals Glucocorticoids act in the dorsal hindbrain to increase arterial pressure

2004 ◽  
Vol 286 (1) ◽  
pp. H458-H467 ◽  
Author(s):  
Deborah A. Scheuer ◽  
Andrea G. Bechtold ◽  
Sylvan S. Shank ◽  
Susan F. Akana
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Glucocorticoid Receptors ◽  
Cardiovascular Effects ◽  
Systemic Circulation ◽  
Dorsal Hindbrain ◽  
Regulation Of Blood Pressure ◽  
Experimental Strategies

Glucocorticoid receptors (GRs) are present at a high density in the nucleus of the solitary tract (NTS), an area of the dorsal hindbrain (DHB) that is critical for blood pressure regulation. However, whether these receptors play any role in the regulation of blood pressure is unknown. We tested the hypothesis that glucocorticoids act in the DHB to increase arterial pressure using two experimental strategies. In one approach, we implanted pellets of corticosterone (Cort) or sham pellets onto the DHB over the NTS. Compared with rats with sham pellets, rats with DHB Cort pellets had an increased ( P < 0.05) mean arterial pressure (111 ± 2 vs. 104 ± 1 mmHg) and heart rate (355 ± 9 vs. 326 ± 5 beats/min) after 4 days. In the second approach, we implanted subcutaneous Cort pellets to increase the systemic Cort concentration and then subsequently implanted pellets of the GR antagonist mifepristone (Mif; previously RU-38486) or sham pellets onto the DHB. Two days of DHB Mif treatment reduced ( P < 0.05) mean arterial pressure in those rats with elevated plasma Cort levels (118 ± 2 vs. 108 ± 1 mmHg for sham vs. Mif DHB pellets). Cort and Mif pellets placed on the dura had no effects on arterial pressure or heart rate, ruling out systemic cardiovascular effects of the steroids. DHB Cort treatment had no effects on plasma Cort concentration or adrenal weight, indicating that the contents of the DHB Cort pellet did not diffuse into the systemic circulation or into the forebrain areas that regulate plasma Cort concentration in concentrations sufficient to produce physiological effects. Immunohistochemistry for the occupied GRs demonstrated that the Cort and Mif from the DHB pellets were delivered to the DHB with minimal diffusion to the ventral hindbrain or forebrain. We conclude that glucocorticoids act in the DHB to increase arterial pressure.

scholarly journals Comparison between esmolol and verapamil in attenuation of cardiovascular stress response to laryngoscopy and endotracheal intubation in elective surgery

2021 ◽  
Vol 12 (7) ◽  
pp. 64-68
Author(s):  
Nitisha Chakraborty ◽  
Sankar Roy ◽  
Debajyoti Sur ◽  
Arunava Biswas ◽  
Dipasri Bhattacharya ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Weight ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Diastolic Blood Pressure ◽  
Endotracheal Intubation ◽  
Efficacy And Safety ◽  
Cardiovascular Stress ◽  
The Mean

Background: Cardiovascular stress due to reflex sympathetic over activity is a great concern during laryngoscopy and endotracheal intubation. Aims and Objectives: To compare the efficacy and safety of esmolol and verapamil for attenuation of hemodynamic effects (heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure) due to laryngoscopy and endotracheal intubation in elective surgical cases. Materials and Methods: A prospective, randomized, double blinded, controlled study was conducted on 60 patients divided equally into 30 each receiving esmolol (2 mg/kg body weight) and verapamil (0.1 mg/kg body weight) respectively. Heart rate, systolic and diastolic blood pressure and mean arterial pressure were recordedat pre-operative stage, after administration of the study drugs, immediately after intubation and at 1 ,3 ,5 minutes after intubation. Data collected were statistically analyzed. Results: The mean systolic blood pressure was lower in the esmolol group at all times of estimation compared with the verapamil group and the difference was at the time of intubation (p value <0.001).The mean diastolic blood pressure was lower in the esmolol group at all times of estimation compared to the verapamil group which was not statistically significant at any time of estimation. The mean arterial pressure was significantly lower at the time of immediately after intubation (p<0.001) in esmolol as compared to verapamil group. Adverse effects in both the study groups were insignificant. Conclusion: Esmololand Verapamil can effectively attenuate the cardiovascular stress to laryngoscopy and endotracheal intubation with the former appears to be a better alternative from efficacy and safety perspectives.

scholarly journals CARDIOVASCULAR RESPONSE TO LARYNGOSCOPY VERSUS FIBER-OPTIC BRONCHOSCOPE DURING OROTRACHEAL INTUBATION IN PATIENTS UNDERGOING ELECTIVE SURGERY

2021 ◽  
Vol 71 (Suppl-1) ◽  
pp. S180-85
Author(s):  
Moazzam Ali ◽  
Maliha Khawar ◽  
Maryam Nazneen ◽  
Zaqawat Nazneen
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Fiber Optic ◽  
Cardiovascular Response ◽  
Macintosh Laryngoscope ◽  
Orotracheal Intubation ◽  
Control Group ◽  
Female Ratio ◽  
The Mean

Objective: To compare the hemodynamic response between flexible fiber optic bronchoscope (FOB) andMacintosh laryngoscope during orotracheal intubation. The secondary objective was to calculate the timerequired for intubation between these two techniques Study Design: Quasi experimental study. Place and Duration of Study: Department of Anesthesia, Frontier Corps Hospital Quetta, from Oct 2016 to Apr2017. Methodology: Eighty patients fulfilling the inclusion/exclusion criteria were included in this study and weredivided randomly into two groups. Group L was intubated with Macintosh laryngoscope (control group) whereas group F was intubated with Fiber optic bronchoscope. Mean arterial pressure and heart rate was recorded as baseline, pre-intubation and then every 01 minute for 03 minutes. Changes in heart rate and mean arterial pressure were recorded in the proforma by another anesthetist who was blinded to the procedure performed. Results: The mean age in group L was 41.23 ± 8.37 years and in group F was 40.73 ± 9.77 years. The mean weight in group L was 69.63 ± 8.92 kg and in group F was 70.6 ± 9.20 kg. In group L, male to female ratio was 26:14 whereas in group F it was 28:12. Mean heart rate and mean arterial pressure did not show significant change over time between groups. Time required for intubation was significantly less (22.45 ± 4.12 secs) in laryngoscopy group versus Fiber-Optic Bronchoscope group (44.68 ± 5.88 secs). Conclusion: In conclusion we can say that our study demonstrated that using laryngoscope or Fiber-OpticBronchoscope for orotracheal..........

Carvedilol Versus Propranolol in the Prevention of Variceal Rebleeding in Hepatic Schistosomiasis: Efficacy and Safety

2021 ◽  
Author(s):  
Chantelli Iamblaudiot Razafindrazoto ◽  
Lova Dany Ella Razafindrabekoto ◽  
Domoina Harivonjy Hasina Laingonirina ◽  
Raveloson Raveloson ◽  
Anjaramalala Sitraka Rasolonjatovo ◽  
...  
Keyword(s):  
Heart Rate ◽  
Portal Hypertension ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Variceal Bleeding ◽  
Efficacy And Safety ◽  
Effective Prevention ◽  
Significant Difference ◽  
Propranolol Group ◽  
The Mean

Abstract Background: The betablockers combined with endoscopic variceal band ligation (EVL) is the most effective prevention of variceal rebleeding. The aim of this study is to evaluate the efficacy and safety of carvedilol compared to propranolol as secondary prevention of variceal bleeding in hepatic schistosomiasis. Methods: All patients with portal hypertension due to schistosomiasis presenting for EVL with at least one episode of variceal bleeding were included and randomized into propranolol + EVL and Carvedilol + EVL groups. Results: Sixty-one patients were selected and randomized into the propranolol group (n=30) and carvedilol group (n=31). We noted less recurrence of bleeding in the carvedilol group (n=1) than in the propranolol group (n=3) (3.33% vs 10%; p=0.30). Bleeding recurrence occurred after 30 days in the carvedilol group and after 5, 45 and 90 days in the propranolol group. At 4 months, a significant reduction in mean arterial pressure (-4.13 mmHg; 95%CI: -6.27 and -1.99; p <0.05) and heart rate (-12.13 mmHg; 95%CI: -13.92 and -10.35; p<0.05) was found in the carvedilol group. There was no significant difference between the two groups on the mean difference in mean arterial pressure. A patient in the carvedilol group presented breathing difficulty. No adverse effects have been demonstrated in the propranolol group. Conclusion: Carvedilol is as effective as propranolol in the prevention of variceal rebleeding in hepatic schistosomiasis.

Role of the vasoconstrictor and antidiuretic activities of vasopressin in inhibition of renin secretion in conscious dogs

1986 ◽  
Vol 250 (1) ◽  
pp. F92-F96 ◽  
Author(s):  
J. Schwartz ◽  
I. A. Reid
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Renin Activity ◽  
Arginine Vasopressin ◽  
Plasma Renin ◽  
Renin Secretion ◽  
Conscious Dogs ◽  
Specific Antagonist

The nature of the activity of vasopressin that is responsible for the inhibition of renin secretion was studied in normally hydrated conscious dogs using intravenous infusions of vasopressin and analogues of vasopressin with selective antidiuretic and vasoconstrictor activity. Vasopressin (1.0 ng . kg-1 . min-1) increased mean arterial pressure (MAP) from 106 +/- 2 to 115 +/- 3 mmHg (P less than 0.05) and decreased heart rate (HR) from 81 +/- 6 to 56 +/- 5 beats/min (P less than 0.001). Plasma renin activity (PRA) decreased from 4.4 +/- 1.1 to 2.4 +/- 0.8 ng . ml-1 . 3 h-1 (P less than 0.05). A specific antagonist of the vasoconstrictor activity of vasopressin, d(CH2)5MeTyrAVP (10 micrograms/kg), completely blocked the cardiovascular and renin responses to vasopressin. A selective vasoconstrictor agonist, 2-phenylalanine-8-ornithine oxytocin (1.0 ng . kg-1 . min-1), increased MAP from 112 +/- 4 to 128 +/- 6 mmHg (P less than 0.001) and decreased HR from 69 +/- 3 to 47 +/- 4 beats/min (P less than 0.001). PRA decreased from 5.5 +/- 1.1 to 2.7 +/- 0.2 ng . ml-1 X 3 h-1 (P less than 0.001). In contrast, a selective antidiuretic agonist, 1-deamino-8-D-arginine vasopressin (1.0 ng . kg-1 . min-1) did not alter PRA, MAP, or HR. These results demonstrate that the acute inhibition of renin secretion by vasopressin in normally hydrated conscious dogs is due to vasoconstrictor rather than antidiuretic activity.

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