Pharmacological blockade of blood pressure and heart rate increases following milk ingestion in 15-day-old SHR and WKY rat pups

1991 ◽  
Vol 50 (3) ◽  
pp. 525-531 ◽  
Author(s):  
Frank M. Scalzo ◽  
Michael M. Myers
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Rat Pups ◽  
Pharmacological Blockade ◽  
Milk Ingestion

Blood pressure and heart rate responses of SHR and WKY rat pups during feeding

1988 ◽  
Vol 44 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Michael M. Myers ◽  
Frank M. Scalzo
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Rat Pups

Cardiovascular effects produced by L-glutamate stimulation of the lateral hypothalamic area

1989 ◽  
Vol 257 (2) ◽  
pp. H540-H552 ◽  
Author(s):  
S. E. Spencer ◽  
W. B. Sawyer ◽  
A. D. Loewy
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Lateral Hypothalamic Area ◽  
Hypothalamic Area ◽  
Pharmacological Blockade ◽  
Stimulation Of

L-Glutamate microinjections into the tuberal region of the lateral hypothalamic area (LHAt) caused a fall in blood pressure and heart rate in pentobarbital-anesthetized rats. The bradycardia was mediated by both beta-adrenergic and muscarinic mechanisms as demonstrated with pharmacological blockade. The hypotension was due to a decrease in cardiac output, not a decrease in total peripheral resistance. In addition, there was a reduction in coronary blood flow. If heart rate was held constant by pharmacological blockade or by electrical cardiac pacing, L-glutamate stimulation of the LHAt still caused a fall in blood pressure. When the electrically paced model was used, this hypotension was due to a fall in cardiac output. In contrast, with the pharmacological blockade of the heart, the hypotension was due to a decrease in the total peripheral resistance. The cardiac output reduction in the paced condition was not mediated solely by either beta-sympathetic or parasympathetic mechanisms as determined by pharmacological blockade. With heart rate held constant by either drugs or pacing, LHAt stimulation did not alter regional blood flow or resistance in any vascular bed, including the coronary circulation. We conclude that L-glutamate stimulation of the LHAt lowers the cardiac output and heart rate by both parasympathetic and beta-adrenergic mechanisms and elicits hypotension by lowering cardiac output in the naive and electrically paced model.

scholarly journals Maintenance of Blood Pressure in Emotional Context-based Autonomic Switching by the Central Nucleus of the Amygdala in Rats

2020 ◽  
Author(s):  
Ko Yamanaka ◽  
Hidefumi Waki
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pressor Response ◽  
Cardiovascular Responses ◽  
Central Nucleus ◽  
Emotional Context ◽  
Neuronal Mechanisms ◽  
Pressor Responses ◽  
Pharmacological Blockade ◽  
Aversive Classical Conditioning

Abstract Proper autonomic control is necessary in making appropriate decisions and actions, but neuronal mechanisms for this function are yet to be determined. Here we show that the amygdala plays a role in autonomic cardiovascular tuning in a dynamically changing environment. We recorded blood pressure and heart rate of head-restrained rats during appetitive and aversive classical conditioning tasks. Rats learned varying associations between conditioned stimuli and unconditioned stimuli in three types of contexts: appetitive, neutral, and aversive blocks. Blood pressure and heart rate in the appetitive block gradually increased after reward-predicting cues, followed by a vigorously increased response to the actual reward. The predictive response was found to be significantly higher than the responses in the neutral and aversive blocks. Blood pressure and heart rate responses to the air puff-predicting cue in the aversive block were significantly lower than that of the responses in the neutral block. Pharmacological blockade of the amygdala has significantly decreased reward-predictive pressor responses in the latter phase, but not in the initial phase of context change. Cardiovascular responses are thus adaptively tuned by positive and negative emotional stimuli, and the central nucleus of the amygdala likely assists in maintaining pressor response tuning based on emotional context.

scholarly journals Effects of Chronic Cholinergic Stimulation Associated With Aerobic Physical Training on Cardiac Morphofunctional and Autonomic Parameters in Spontaneously Hypertensive Rats

2021 ◽  
Author(s):  
Camila B. Gardim ◽  
Ana Catarine V. Oliveira ◽  
Bruno Augusto Aguilar ◽  
Stella V. Philbois ◽  
Hugo C. D. Souza
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Physical Training ◽  
Spontaneously Hypertensive Rats ◽  
Low Frequency ◽  
Pyridostigmine Bromide ◽  
Cholinergic Stimulation ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Pharmacological Blockade

Abstract We investigated in spontaneously hypertensive rats (SHR) the hemodynamic, cardiac morphofunctional, and cardiovascular autonomic adaptations after a protocol of aerobic physical training associated with chronic cholinergic stimulation. Fifty-four SRH were divided into two groups: trained and untrained. Afterward, each group was subdivided into three smaller groups: vehicle, treated with pyridostigmine bromide at 5mg/kg/day, and at 15mg/kg/day. The following protocols were assessed: echocardiography, autonomic double pharmacological blockade, analysis of heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS). Physical training and pyridostigmine bromide reduced blood pressure and heart rate and increased vagal participation in cardiac tonic autonomic balance. Associated the responses were potentialized. Pyridostigmine bromide increased the oscillation of low frequency (LF:0.2-0.75Hz) and high frequency (HF:0.75-3Hz) of HRV. However, the association with physical training attenuated HF oscillations. Pyridostigmine bromide also increased LF oscillations of BPV. Both treatments promoted morphofunctional adaptations and associated increased the ejection volume, ejection fraction, cardiac output, and cardiac index. In conclusion, the association of pyridostigmine bromide and physical training promoted greater benefits in hemodynamic parameters and increase vagal influence on cardiac autonomic tonic balance. Nonetheless, pyridostigmine bromide alone seems to negatively affect BPV, while the association of treatment negatively influences HRV.

Caffeine and Placebo Expectation

2007 ◽  
Vol 21 (2) ◽  
pp. 91-99 ◽  
Author(s):  
Yunfeng Sun ◽  
Yinling Zhang ◽  
Ning He ◽  
Xufeng Liu ◽  
Danmin Miao
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Sleep Deprivation ◽  
Cognitive Performance ◽  
Cognitive Functions ◽  
Cardiovascular Regulation ◽  
Double Blind ◽  
Positive Effects ◽  
Pressure Tests ◽  
Healthy Males

Abstract. Caffeine placebo expectation seems to improve vigilance and cognitive performance. This study investigated the effect of caffeine and placebo expectation on vigilance and cognitive performance during 28 h sleep deprivation. Ten healthy males volunteered to take part in the double-blind, cross-over study, which required participants to complete five treatment periods of 28 h separated by 1-week wash-out intervals. The treatments were no substance (Control); caffeine 200 mg at 00:00 (C200); placebo 200 mg at 00:00 (P200); twice caffeine 200 mg at 00:00 and 04:00 (C200-C200); caffeine 200 mg at 00:00 and placebo 200 mg at 04:00 (C200-P200). Participants were told that all capsules were caffeine and given information about the effects of caffeine to increase expectation. Vigilance was assessed by a three-letter cancellation test, cognitive functions by the continuous addition test and Stroop test, and cardiovascular regulation by heart rate and blood pressure. Tests were performed bihourly from 00:00 to 10:00 of the second day. Results indicated that C200-P200 and C200-C200 were more alert (p < .05) than Control and P200. Their cognitive functions were higher (p < .05) than Control and P200. Also, C200-P200 scored higher than C200 in the letter cancellation task (p < .05). No test showed any significant differences between C200-P200 and C200-C200. The results demonstrated that the combination of caffeine 200 mg and placebo 200 mg expectation exerted prolonged positive effects on vigilance and cognitive performance.

Reduction in Pain Sensitivity from Pharmacological Elevation of Blood Pressure in Persons with Chronically Low Blood Pressure

2009 ◽  
Vol 23 (3) ◽  
pp. 104-112 ◽  
Author(s):  
Stefan Duschek ◽  
Heike Heiss ◽  
Boriana Buechner ◽  
Rainer Schandry
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pain Sensitivity ◽  
Pain Threshold ◽  
Pain Perception ◽  
Drug Effects ◽  
Pressure Effects ◽  
Double Blind ◽  
Low Blood Pressure ◽  
Present Trial

Recent studies have revealed evidence for increased pain sensitivity in individuals with chronically low blood pressure. The present trial explored whether pain sensitivity can be reduced by pharmacological elevation of blood pressure. Effects of the sympathomimetic midodrine on threshold and tolerance to heat pain were examined in 52 hypotensive persons (mean blood pressure 96/61 mmHg) based on a randomized, placebo-controlled, double-blind design. Heat stimuli were applied to the forearm via a contact thermode. Confounding of drug effects on pain perception with changes in skin temperature, temperature sensitivity, and mood were statistically controlled for. Compared to placebo, higher pain threshold and tolerance, increased blood pressure, as well as reduced heart rate were observed under the sympathomimetic condition. Increases in systolic blood pressure between points of measurement correlated positively with increases in pain threshold and tolerance, and decreases in heart rate were associated with increases in pain threshold. The findings underline the causal role of hypotension in the augmented pain sensitivity related to this condition. Pain reduction as a function of heart rate decrease suggests involvement of a baroreceptor-related mechanism in the pain attrition. The increased proneness of persons with chronic hypotension toward clinical pain is discussed.

Sex Differences in Cardiovascular Reactivity

2009 ◽  
Vol 23 (2) ◽  
pp. 77-84 ◽  
Author(s):  
Matthew C. Whited ◽  
Kevin T. Larkin
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Sex Differences ◽  
Gender Roles ◽  
Cardiovascular Reactivity ◽  
Task Type ◽  
Conflict Task ◽  
Men And Women ◽  
Conflicting Evidence ◽  
Blood Pressure Responses

Sex differences in cardiovascular reactivity to stress are well documented, with some studies showing women having greater heart rate responses than men, and men having greater blood pressure responses than women, while other studies show conflicting evidence. Few studies have attended to the gender relevance of tasks employed in these studies. This study investigated cardiovascular reactivity to two interpersonal stressors consistent with different gender roles to determine whether response differences exist between men and women. A total of 26 men and 31 women were assigned to either a traditional male-oriented task that involved interpersonal conflict (Conflict Task) or a traditional female-oriented task that involved comforting another person (Comfort Task). Results demonstrated that women exhibited greater heart rate reactions than men independent of the task type, and that men did not display a higher reactivity than women on any measure. These findings indicate that sex of participant was more important than gender relevance of the task in eliciting sex differences in cardiovascular responding.

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