Cardiovascular Reactivity in the Dog after Chemical Sympathectomy with 6-Hydroxy dopamine

1974 ◽  
Vol 52 (3) ◽  
pp. 590-601 ◽  
Author(s):  
Pierre Gauthier ◽  
Réginald A. Nadeau ◽  
Jacques De Champlain
Keyword(s):  
Blood Pressure ◽  
Cardiovascular Reactivity ◽  
Blood Pressure Response ◽  
Cardiovascular Responses ◽  
Chemical Sympathectomy ◽  
Intravenous Injections ◽  
Pressor Responses ◽  
Before And After ◽  
Anesthetized Dogs ◽  
6 Hydroxydopamine

The cardiovascular responses to intravenous injections of noradrenaline, isoproterenol, and phenylephrine were studied in unanesthetized and anesthetized dogs before and after chemical sympathectomy with 6-hydroxydopamine (6-OH-DA), 50 mg/kg. Three days after 6-OH-DA pretreatment, the blood pressure response to noradrenaline in unanesthetized dogs was increased significantly despite the presence of a marked reflex slowing of the heart. Chronotropic and pressor responses to noradrenaline were likewise increased in anesthetized and vagotomized dogs after 6-OH-DA pretreatment. Not only was the amplitude of the responses to noradrenaline increased after 6-OH-DA pretreatment but their duration was likewise prolonged. In contrast, the cardiovascular responses to isoproterenol and phenylephrine did not appear significantly changed in 6-OH-DA pretreated dogs. These results are consistent with the development of a presynaptic type of supersensitivity in dogs pretreated with 6-OH-DA.

Cardiovascular responses during feeding in newborn lambs

1989 ◽  
Vol 257 (3) ◽  
pp. R568-R573
Author(s):  
B. L. Langille ◽  
S. L. Adamson ◽  
S. A. Jones
Keyword(s):  
Blood Pressure ◽  
Skeletal Muscle ◽  
Gastrointestinal Tract ◽  
Pressor Response ◽  
Sympathetic Innervation ◽  
Cardiovascular Responses ◽  
Bottle Feeding ◽  
Chemical Sympathectomy ◽  
Thyroid Glands ◽  
6 Hydroxydopamine

We examined the cardiovascular responses to bottle feeding in newborn lambs. Feeding induced a persistent rise in blood pressure, from 76.3 +/- 1.9 mmHg to 114 +/- 3.8 mmHg, that lasted for the duration of the feeding episode. This was accompanied by a transient tachycardia that lasted for approximately 10 s at the beginning of each feeding episode. Vasoconstriction of the hindlimb circulation, the gastrointestinal tract, kidneys, and adrenal and thyroid glands contributed to the pressor response, whereas changes in skeletal muscle resistance were not statistically significant. Of tissues assessed, only those actively involved in feeding (tongue and esophagus) vasodilated. Feeding tachycardia was greatly inhibited or abolished by the beta-blocker propranolol but the alpha-blocker phentolamine caused only moderate inhibition of the pressor response. Furthermore, chemical sympathectomy with 6-hydroxydopamine delayed the onset of the pressor response but did not abolish the ultimate rise in pressure. These findings indicate that feeding causes a significant pressor response in newborn lambs that is only partially mediated by sympathetic innervation.

scholarly journals State Anxiety Is Associated with Cardiovascular Reactivity in Young, Healthy African Americans

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mildred A. Pointer ◽  
Sadiqa Yancey ◽  
Ranim Abou-Chacra ◽  
Patricia Petrusi ◽  
Sandra J. Waters ◽  
...  
Keyword(s):  
Blood Pressure ◽  
African Americans ◽  
Cardiovascular Reactivity ◽  
Trait Anxiety ◽  
State Anxiety ◽  
Blood Pressure Response ◽  
Cold Pressor ◽  
Pressure Response ◽  
Anxiety State ◽  
Stress Tests

Although several studies have shown that enhanced cardiovascular reactivity can predict hypertension development in African Americans, these findings have not been consistent among all studies examining reactivity and hypertension susceptibility. This inconsistency may be explained by the influence of anxiety (state and trait) on the blood pressure response to stress. Therefore, this study sought to determine whether anxiety is associated with blood pressure response to cold pressor (CP) and anger recall (AR) stress tests in young healthy African Americans. Modeling using state and trait anxiety revealed that state anxiety predicts systolic (SBP) and diastolic blood pressure DBP response to CP and AR (P≤0.02). Interestingly, state anxiety predicted heart rate changes only to CP (P<0.01;P=0.3for AR). Although trait anxiety was associated with SBP response to AR and not CP, it was not a significant predictor of reactivity in our models. We conclude that anxiety levels may contribute to the variable blood pressure response to acute stressors and, therefore, should be assessed when performing cardiovascular reactivity measures.

scholarly journals Chronotopic and blood pressure response to oral glucose load in chagas' disease

1994 ◽  
Vol 112 (3) ◽  
pp. 602-606 ◽  
Author(s):  
Maria Elena Guariento ◽  
Elza Olga ◽  
Ana Muscelli ◽  
José Antonio Rocha Gontijo
Keyword(s):  
Blood Pressure ◽  
Cardiovascular Response ◽  
Blood Pressure Response ◽  
Serum Insulin ◽  
Oral Glucose ◽  
Oral Glucose Load ◽  
Autonomic Nervous System Dysfunction ◽  
Glucose Levels ◽  
Pressor Responses ◽  
Insulin Activity

Cardiac chronotropic and pressor responses after an oral load of glucose were assessed in sixteen Chagasic subjects and 28 controls by means of blood pressure and pulse rate measurements. Cardiovascular response was correlated with serum insulin and glucose levels. The experiment identified a subgroup of Chagasic subjects (n=8) with a hypoinsulinemic behavior presenting less chronotropic and pressor responses than controls. This may indicate a lower insulin activity and/or an early Autonomic Nervous System dysfunction in this subgroup.

Pressor responses to norepinephrine in humans before and after corticosteroids

1962 ◽  
Vol 203 (5) ◽  
pp. 961-963 ◽  
Author(s):  
Mohinder P. Sambhi ◽  
Max H. Weil ◽  
Vasant N. Udhoji
Keyword(s):  
Human Subject ◽  
Normal Subjects ◽  
Adrenal Function ◽  
Variance Analysis ◽  
Acute Administration ◽  
Intravenous Injections ◽  
Pressor Responses ◽  
Before And After

Pressor responses produced by intravenous injections of graded doses of norepinephrine were recorded in ten normal subjects before and after pharmacologic doses of glucocorticoids. Two subjects had been pretreated with 9α-fluorocortisol. Although a considerable variation was found in the responsiveness to repeated norepinephrine injections, variance analysis demonstrated that administration of adrenal cortical hormones and their analogues did not significantly alter the response. These observations do not support the hypothesis that acute administration of corticosteroids in large doses potentiates the pressor effects of catecholamines in the human subject with normal adrenal function.

Life Events, Cardiovascular Reactivity, and Risk Behavior in Adolescent Boys

PEDIATRICS ◽  
1995 ◽  
Vol 96 (6) ◽  
pp. 1101-1105
Author(s):  
Sai-Woon Liang ◽  
John M. Jemerin ◽  
Jeanne M. Tschann ◽  
Charles E. Irwin ◽  
Diane W. Wara ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Risk Behavior ◽  
Arterial Blood Pressure ◽  
Life Events ◽  
Cardiovascular Reactivity ◽  
Mean Arterial Blood Pressure ◽  
Cardiovascular Responses ◽  
Adolescent Boys ◽  
Positive Life Events ◽  
Arterial Blood

Background. Risk behavior contributes to injuries, one of the most important sources of morbidity and mortality in adolescents. Although research has shown that environmental stress makes adolescents more likely to engage in risk behavior and to sustain injuries, the magnitude of these associations has been small. Little is known about the role of individual differences in psychobiologic reactivity to stress in moderating the impact of stressful events. In this study, we examined associations among environmental stressors, cardiovascular reactivity to stress, and the level of risk behavior in adolescent boys. Methods. Twenty-four 14- to 16-year-old boys underwent a laboratory protocol designed to measure responses to psychologically and physically stressful tasks. Changes in heart rate and mean arterial blood pressure were measured serially at standard points in the protocol, and levels of positive and negative life events and recent risk behavior were measured using self-report questionnaires. Results. Neither life events nor cardiovascular reactivity were independently associated with risk behavior. Positive life events and mean arterial blood pressure reactivity significantly interacted, however, in predicting risk behavior (R2 increment = .25). Boys with high reactivity who reported numerous positive life events engaged in markedly less risk behavior than their peers. Conclusion. We conclude that adolescents with exaggerated cardiovascular responses to laboratory stressors are associated with less risk behavior in a setting of positive life circumstances. This result suggests that reactivity may exert protective, rather than harmful, influences in some environments.

Role of the descending pressor pathway in the conscious and pentobarbital-anesthetized dog

1978 ◽  
Vol 234 (2) ◽  
pp. H152-H156
Author(s):  
G. S. Geis ◽  
G. Barratt ◽  
R. D. Wurster
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular Control ◽  
Conscious Dogs ◽  
Cardiovascular Parameters ◽  
Bilateral Carotid ◽  
Before And After ◽  
Anesthetized Dogs ◽  
Conscious Animals

Resting cardiovascular parameters and the responses to bilateral carotid occlusions (BCO) were monitored in pentobarbital-anesthetized and conscious dogs before and after placing lesions in the dorsolateral funiculi at C7-C8 and after spinal transections at C7. Pre- and postlesion blood pressure (BP) and heart rate (HR) responses to exercise were also monitored. The lesions significantly attenuated the responses to BCO and decreased resting BP in anesthetized dogs. Yet neither resting HR in anesthetized or conscious dogs nor the resting BP in conscious dogs was affected by the lesions. Subsequent spinal transections significantly decreased resting HR and BP and the responses to BCO but did not affect the BP response to BCO in anesthetized dogs as compared with corresponding postlesion parameters. BP responses to exercise were significantly attenuated by the lesions, but HR responses were not affected. Since stimulation and BP studies indicated that the descending pressor pathway had been ablated, the data suggest that the pathway mediates BP and HR responses to BCO in pentobarbital-anesthetized and conscious dogs. It does not maintain resting HR in anesthetized or conscious animals, and the resting BP in conscious dogs. This pathway is important for BP responses to exercise but is not necessary for HR responses. Finally, other spinal pathways are involved in cardiovascular control.

Prostaglandin synthetase inhibitors do not decrease hypoxic pulmonary vasoconstriction

1976 ◽  
Vol 41 (5) ◽  
pp. 714-718 ◽  
Author(s):  
E. K. Weir ◽  
I. F. McMurtry ◽  
A. Tucker ◽  
J. T. Reeves ◽  
R. F. Grover
Keyword(s):  
Pressor Response ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Prostaglandin Synthesis ◽  
Pulmonary Vasoconstriction ◽  
Pressor Responses ◽  
Hypoxic Vasoconstriction ◽  
Before And After ◽  
Anesthetized Dogs ◽  
Prostaglandin Antagonists ◽  
The Stability

Prostaglandins are naturally occurring substances with powerful vasoactive effects that are released from tissues during hypoxia or ischemia. Several workers have suggested that a prostaglandin may help to mediate the pulmonary vascular pressor response to alveolar hypoxia. To investigate this possibility, we have measured the pressor responses to hypoxia before and after prostaglandin synthesis antagonism with meclofenamate in eight anesthetized dogs, two groups of awake calves (n=10 and =5), and nine isolated, perfused rat lungs. In addition, synthesis was inhibited by the use of indomethacin in nine additional dogs. The stability of the pulmonary vascular response to repeated hypoxic challenges was demonstrated in nine other dogs. In each species and with both prostaglandin antagonists, the pulmonary pressorresponses to hypoxia were significantly increased rather than reduced. We conclude that prostaglandins do not mediate the pulmonary vasoconstriction caused by hypoxia. The consistent increase observed suggests that hypoxic vasoconstriction stimulates prostaglandin synthesis, the net effect of which is pulmonary vasodilatation which opposes the constriction.

Role of nitric oxide deficiency in the development of hypertension in hydronephrotic animals

2008 ◽  
Vol 294 (2) ◽  
pp. F362-F370 ◽  
Author(s):  
Mattias Carlström ◽  
Russell D. Brown ◽  
Jenny Edlund ◽  
Johan Sällström ◽  
Erik Larsson ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Blood Pressure Response ◽  
Chronic Administration ◽  
Renal Tissue ◽  
Tubuloglomerular Feedback ◽  
Before And After ◽  
Nitric Oxide Deficiency ◽  
Pressure Natriuresis ◽  
Salt Sensitive Hypertension

Hydronephrotic animals develop renal injury and hypertension, which is associated with an abnormal tubuloglomerular feedback (TGF). The TGF sensitivity is coupled to nitric oxide (NO) in the macula densa. The involvement of reduced NO availability in the development of hypertension in hydronephrosis was investigated. Hydronephrosis was induced by ureteral obstruction in young rats. Blood pressure and renal excretion were measured in adulthood, under different sodium conditions, and before and after chronic administration of either NG-nitro-l-arginine methyl ester (l-NAME) or l-arginine. Blood samples for ADMA, SDMA, and l-arginine analysis were taken and the renal tissue was used for histology and determination of NO synthase (NOS) proteins. TGF characteristics were determined by stop-flow pressure technique before and after administration of 7-nitroindazole (7-NI) or l-arginine. Hydronephrotic animals developed salt-sensitive hypertension, which was associated with pressure natriuresis and diuresis. The blood pressure response to l-NAME was attenuated and l-arginine supplementation decreased blood pressure in hydronephrotic animals, but not in the controls. Under control conditions, reactivity and sensitivity of the TGF response were greater in the hydronephrotic group. 7-NI administration increased TGF reactivity and sensitivity in control animals, whereas, in hydronephrotic animals, neuronal NOS (nNOS) inhibition had no effect. l-Arginine attenuated TGF response more in hydronephrotic kidneys than in controls. The hydronephrotic animals displayed various degrees of histopathological changes. ADMA and SDMA levels were higher and the renal expressions of nNOS and endothelial NOS proteins were lower in animals with hydronephrosis. Reduced NO availability in the diseased kidney in hydronephrosis, and subsequent resetting of the TGF mechanism, plays an important role in the development of hypertension.

Hypercapnic blood pressure response is greater during the luteal phase of the menstrual cycle

1996 ◽  
Vol 81 (5) ◽  
pp. 2142-2146 ◽  
Author(s):  
N. Edwards ◽  
I. Wilcox ◽  
O. J. Polo ◽  
C. E. Sullivan
Keyword(s):  
Blood Pressure ◽  
Menstrual Cycle ◽  
Luteal Phase ◽  
Blood Pressure Response ◽  
Cardiovascular Responses ◽  
Follicular Phase ◽  
Pressure Response ◽  
Serum Progesterone ◽  
Menstrual Cycles ◽  
Blood Pressure Responses

Edwards, N., I. Wilcox, O. J. Polo, and C. E. Sullivan.Hypercapnic blood pressure response is greater during the luteal phase of the menstrual cycle. J. Appl. Physiol. 81(5): 2142–2146, 1996.—We investigated the cardiovascular responses to acute hypercapnia during the menstrual cycle. Eleven female subjects with regular menstrual cycles performed hypercapnic rebreathing tests during the follicular and luteal phases of their menstrual cycles. Ventilatory and cardiovascular variables were recorded breath by breath. Serum progesterone and estradiol were measured on each occasion. Serum progesterone was higher during the luteal [50.4 ± 9.6 (SE) nmol/l] than during the follicular phase (2.1 ± 0.7 nmol/l; P < 0.001), but serum estradiol did not differ (follicular phase, 324 ± 101 pmol/l; luteal phase, 162 ± 71 pmol/l; P = 0.61). The systolic blood pressure responses during hypercapnia were 2.0 ± 0.3 and 4.0 ± 0.5 mmHg/Torr (1 Torr = 1 mmHg rise in end-tidal [Formula: see text]) during the follicular and luteal phases, respectively, of the menstrual cycle ( P < 0.01). The diastolic blood pressure responses were 1.1 ± 0.2 and 2.1 ± 0.3 mmHg/Torr during the follicular and luteal phases, respectively ( P < 0.002). Heart rate responses did not differ during the luteal (1.7 ± 0.3 beats ⋅ min−1 ⋅ Torr−1) and follicular phases (1.4 ± 0.3 beats ⋅ min−1 ⋅ Torr−1; P = 0.59). These data demonstrate a greater pressor response during the luteal phase of the menstrual cycle that may be related to higher serum progesterone concentrations.

Cardiovascular Responses to Sustained Handgrip in Normal Subjects and in Patients with Diabetes Mellitus: A Test of Autonomic Function

1974 ◽  
Vol 46 (3) ◽  
pp. 295-306 ◽  
Author(s):  
D. J. Ewing ◽  
J. B. Irving ◽  
F. Kerr ◽  
J. A. W. Wildsmith ◽  
B. F. Clarke
Keyword(s):  
Diabetes Mellitus ◽  
Blood Pressure ◽  
Blood Pressure Response ◽  
Muscle Tension ◽  
Maximum Voluntary Contraction ◽  
Pressure Rise ◽  
Cardiovascular Responses ◽  
Normal Subjects ◽  
Simple Method ◽  
Patients With Diabetes

1. The blood pressure and heart rate responses to static muscular exercise were measured in sixty normal subjects and 124 patients with diabetes mellitus, aged 25–54 years, during a standardized sustained handgrip test at 30% maximum voluntary contraction (MVC). 2. The normal range of the response was established. Females had a smaller blood pressure rise than males, and their MVC was lower. In the normal subjects there was a significant correlation between the size of the MVC and the height of the blood pressure response. The absolute muscle tension exerted should be taken into account in addition to the percentage MVC, when comparing responses to sustained exercise in different disease states. 3. The diabetic subjects showed a similar sex difference in their response. The mean diastolic blood pressure rises were smaller than in the control groups, both in males and females, but this was related to a smaller mean MVC. 4. Twenty-two of the diabetic subjects had an abnormally low response to sustained handgrip, which was not related to age, duration of diabetes, treatment or control of the disease. These diabetic subjects probably had damage of the autonomic fibres mediating the response. The findings would suggest that sustained handgrip is a useful and simple method of detecting involvement of the autonomic nervous system in diabetes.

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