Trigeminal and chemoreceptor contributions to bradycardia during voluntary dives in rats

1997 ◽  
Vol 273 (2) ◽  
pp. R814-R822 ◽  
Author(s):  
P. F. McCulloch ◽  
G. P. Ollenberger ◽  
L. K. Bekar ◽  
N. H. West

This study investigates the importance of chemoreceptive and trigeminal information during voluntarily initiated diving in rats. The heart rate responses to simulated diving are unaffected by chemoreceptor drive [McCulloch, P.F., and N. H. West. Am. J. Physiol. 263 (Regulatory Integrative Comp. Physiol. 32): R1049-R1056, 1992] but are reversibly eliminated by infusion of glutamate receptor antagonists into the spinal trigeminal nuclei [McCulloch, P. F., I. A. Paterson, and N. H. West. Am. J. Physiol. 269 (Regulatory Integrative Comp. Physiol. 38): R669-R677, 1995]. To investigate the role of chemoreceptor drive in conscious dives, rats were made hypercapnic, hyperoxic, or hypoxic predive. The role of trigeminal input was explored by infusing the glutamatergic antagonists D-2-amino-7-phosphoheptanoic acid and 6,7-dinitroquinoxaline-2,3-dione into the region of the trigeminal nuclei. The alteration of arterial blood gases predive had no effect on diving bradycardia. Trigeminal blockade reduced the intensity of the bradycardia but did not abolish it. Chemoreceptor input does not play a significant role in determining heart rate during conscious diving in rats. The attenuation, rather than abolition, of bradycardia on trigeminal blockade suggests either that we achieved incomplete blockade or that an additional spectrum of sensory inputs not present in simulated diving is important in determining the underwater heart rate during conscious diving in rats.

2021 ◽  
Vol 8 (10) ◽  
pp. 1-7
Author(s):  
Aulia Rahman ◽  
Tambar Kembaren ◽  
Endang Sembiring

Background: The lungs are one of the primary target organs for HIV disease and a major source of morbidity and mortality, among others, caused by Pneumocystis carinii pneumonia (PCP) or recurrent bacterial pneumonia. In developing countries, the incidence of PCP infection has soared, with high mortality rates ranging from 20% to 80%. The increase in serum LDH plays an important role in determining the severity of the disease. This study aims to determine the role of LDH examination as a diagnostic tool for PCP and Arterial Blood Gases (ABG) in HIV and AIDS patients. Method: This research is an analytical study using an observational diagnostic test design, conducted from November 2020-January 2021 at the HIV Treatment Room at H. Adam Malik Hospital, Medan with 158 subjects. We calculate the value of sensitivity, specificity, positive predictive value, and negative predictive value. Results: 75.3% of the total sample was male, with the highest age group being 30-39 years old (46.2%) 126 samples (79.7%) had CD4 levels 200 cells/mm3, 98 samples (62%) had LDH levels > 500 U/L. In this study, 113 samples (71.5%) fell into the ABG criteria [PaO2] <70 mmHg). LDH has superior sensitivity and specificity value compared to ABG examination. In this case PaO2 or A-A DO2 in diagnosing PCP in HIV-AIDS patients. Conclusion: LDH examination combined with clinical and radiological examinations has good sensitivity and specificity in the diagnosis of PCP. Keywords: HIV, AIDS, Lactate dehydrogenase, PCP.


PEDIATRICS ◽  
1950 ◽  
Vol 6 (4) ◽  
pp. 557-572
Author(s):  
DONALD E. CASSELS ◽  
MINERVA MORSE ◽  
W. E. ADAMS

The effect of the patent ductus arteriosus on the circulation and on the arterial blood gases and pHs has been studied. The pulmonary blood flow diminished 19.6 to 61.8% following ligation in 12 cases examined. The blood volume diminished following closure of the ductus in most cases. Likewise, the heart rate lessened and the pulse pressure was lower after surgery. Arterial oxygen saturation was low preoperatively in some cases and in most instances postoperatively, and this low value sometimes persisted. Some aspects of the data presented have been discussed in detail.


Author(s):  
Yiannis Papachatzakis ◽  
Pantelis Theodoros Nikolaidis ◽  
Sofoklis Kontogiannis ◽  
Georgia Trakada

High-flow oxygen through nasal cannula (HFNC) provides adequate oxygenation and can be an alternative to noninvasive ventilation (NIV) for patients with hypoxemic respiratory failure. The aim of the present study was to assess the efficacy of HFNC versus NIV in hypercapnic respiratory failure. Patients (n = 40) who were admitted to the Emergency Department of Alexandra Hospital due to hypercapnic respiratory failure (PaCO2 ≥ 45 mmHg) were randomized assigned into two groups, i.e., an intervention group (use of HFNC, n = 20) and a control group (use of NIV, n = 20). During their hospitalization in the Intensive Care Unit, vital signs (respiratory and heart rate, arterial blood pressure) and arterial blood gases (ABG) were closely monitored on admission, after 24 h and at discharge. No difference between the two groups regarding the duration of hospitalization and the use of HFNC or NIV was observed (p > 0.05). On admission, the two groups did not differ in terms of gender, age, body mass index, APACHE score, predicted death rate, heart rate, arterial blood pressure and arterial blood gases (p > 0.05). Respiratory rate in the HFNC group was lower than in the NIV group (p = 0.023). At discharge, partial carbon dioxide arterial pressure (PaCO2) in the HFNC group was lower than in the NIV group (50.8 ± 9.4 mmHg versus 59.6 ± 13.9 mmHg, p = 0.024). The lowerPaCO2 in the HFNC group than in the NIV group indicated that HFNC was superior to NIV in the management of hypercapnic respiratory failure.


1987 ◽  
Vol 252 (5) ◽  
pp. R848-R852 ◽  
Author(s):  
D. G. Davies ◽  
J. A. Sexton

The role of changes in brain extracellular fluid [H+] in the control of breathing during anoxia was studied in unanesthetized turtles, Chrysemys scripta. Ventilation, [minute ventilation (VE), tidal volume (VT), and breathing frequency (f)], cerebral extracellular fluid (ECF) pH, and arterial blood gases were measured at 25 degrees C during a 30-min control period (room air), 30 min of anoxia (100% N2 breathing), and 60 min of recovery (room air). ECF pH was measured in the cerebral cortex with a glass microelectrode (1-2 micron tip diam). Large changes in ventilation, ECF [H+], and arterial blood gases were observed. The predominant ventilatory response was an increase in f with a slight increase in VT. A correlation was observed between ECF [H+] and f, which suggested that central chemoreceptor stimulation was involved in the ventilatory response.


2018 ◽  
Vol 58 (9) ◽  
pp. 1603 ◽  
Author(s):  
I. Benu ◽  
L. A. Fitzpatrick ◽  
M. J. Callaghan ◽  
N. Tomkins ◽  
A. J. Parker

The objective of this study was to investigate the effects of nitrate treatment on the arterial blood gas and haemoglobin fractions from Bos indicus steers after exercise. Bos indicus steers (n = 12; mean bodyweight ± s.e.m., 397 kg ± 10.84 kg) were used in this experiment to investigate the effects of three dose rates of nitrate salts (0, 30 or 50 g of nitrate/day) on arterial blood gases, methaemoglobin concentration, carboxyhaemoglobin concentration, oxyhaemoglobin concentration, total haemoglobin concentration, haematocrit, heart rate, and respiratory rate after exercise. Increasing the dose rate of nitrate resulted in a decrease in the partial pressure of oxygen (P = 0.004) in blood. Steers treated with 50 g nitrate/day had a decrease in oxyhaemoglobin concentration (P = 0.001) and a concomitant increase in methaemoglobin (P = 0.001) and carboxyhaemoglobin (P = 0.001) compared with steers treated with 0 or 30 g nitrate/day. Steers dosed with 50 g of nitrate had greater heart rates immediately after the exercise regimen compared with the steers dosed with 30 g of nitrate (P = 0.043) or no nitrate (P = 0.018). There was no difference between treatments for respiratory rate (P = 0.673) or rectal temperature (P = 0.207) after the exercise regimen. Feeding nitrate to Bos indicus cattle results in a decrease in the oxygen carrying capacity of their blood. It is likely that doses of nitrate greater than 50 g per day for this class of animal could induce hypoxaemic trauma if cattle have exercise imposed after consuming a nitrate supplement.


2002 ◽  
Vol 259 (2) ◽  
pp. 63-66 ◽  
Author(s):  
Oguz Ögretmenoglu ◽  
T. Yılmaz ◽  
Keikavos Rahimi ◽  
Serdar Aksöyek

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