CO2asphyxia increases plasma norepinephrine in rats via sympathetic nerves

1998 ◽  
Vol 274 (1) ◽  
pp. R19-R22 ◽  
Author(s):  
Vicky Borovsky ◽  
Mike Herman ◽  
Gail Dunphy ◽  
Ann Caplea ◽  
Daniel Ely
Keyword(s):  
High Performance ◽  
Sympathetic Nerves ◽  
Female Rats ◽  
Plasma Norepinephrine ◽  
Specific Response ◽  
Spontaneously Hypertensive ◽  
Male And Female Rats ◽  
Y Chromosomes ◽  
Sympathetic Nerve Ending ◽  
Wistar Kyoto

The objective of this study was to determine whether the plasma norepinephrine (NE) increase in rats exposed to CO2asphyxia was due to adrenal gland release or sympathetic nerve ending (SNS) release. Plasma NE was measured by high-performance liquid chromatography in hypertensive and normotensive rats using the following protocol: control session, CO2exposure, N2exposure, reserpine + CO2, and adrenalectomy + CO2. Four strains of male and female rats were used: spontaneously hypertensive rats, Wistar-Kyoto rats, and two congenic strains with different Y chromosomes. The same rats were used throughout the experiment ( n = 80). Blood pressure measured by aortic telemetry increased ∼50–60 mmHg in response to CO2in all strains. CO2increased NE 6–10× in all strains and both genders. N2produced a significant increase in NE (73% of CO2response). Reserpine significantly decreased (67%) plasma NE after CO2. Adrenalectomy did not significantly reduce the NE response to CO2. In conclusion, the increase in plasma NE after CO2was associated with SNS release and not adrenal medullary release, was mainly due to hypoxia, and was not a specific response to CO2.

Sex Differences of Hepatic Conjugation of Bilirubin Determine its Maximal Biliary Excretion in Non-Anaesthetized Male and Female Rats

1983 ◽  
Vol 64 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Maurizio Muraca ◽  
Jan De Groote ◽  
Johan Fevery
Keyword(s):  
Biliary Excretion ◽  
High Performance ◽  
Relative Proportion ◽  
Female Rats ◽  
Male Rats ◽  
Transferase Activity ◽  
Hepatic Transport ◽  
Male And Female Rats ◽  
Udp Glucuronosyltransferase ◽  
Rate Limiting

1. Hepatic bilirubin UDP-glucuronosyltransferase activity was higher in female than in male rats; gonadectomy decreased enzyme activity in females and increased it in males. This sex difference in bilirubin conjugation was further used to evaluate the effect of differences in conjugation on the maximal biliary excretion of bilirubin in the non-anaesthetized rat. 2. After infusion of bilirubin, the maximal biliary excretory rate (Tm) and maximal concentration of bilirubin in bile were respectively 70% and 40% higher in female than in male rats; these values were decreased in females after ovariectomy and increased in males after orchiectomy. A linear relationship was found (r = 0.86; P < 0.001) between bilirubin Tm and hepatic bilirubin UDP-glucuronosyltransferase activity in the four groups of rats, suggesting that conjugation was the rate-limiting step for the maximal hepatic transport of bilirubin. 3. At the end of bilirubin infusion, bilirubin conjugates in serum, determined by alkaline methanolysis and high-performance liquid chromatography, ranged from 0.5 to 1.4% of total bilirubin. Therefore no significant reflux of conjugated bilirubin occurred during saturation of the hepatic transport of the pigment, once more suggesting that the secretory step was not rate-limiting. 4. The composition of bilirubin conjugates in bile was similar in the four groups of rats, despite significant differences in transferase activity. This suggests that the relative proportion of bilirubin mono- and di-conjugates in bile is affected by factors other than transferase activity alone. Relatively more monoconjugates were excreted under the bilirubin load than in basal conditions.

INFLUENCE OF THE REPRODUCTIVE STATE AT THE TIME OF OPERATION ON THE EARLY RESPONSE TO OVARIECTOMY IN THE RAT

1972 ◽  
Vol 53 (1) ◽  
pp. 47-57 ◽  
Author(s):  
C. M. TAPPER ◽  
F. NAFTOLIN ◽  
K. BROWN-GRANT
Keyword(s):  
Feedback System ◽  
Early Response ◽  
Female Rats ◽  
Male Rats ◽  
Specific Response ◽  
Gonadal Steroid ◽  
Reproductive State ◽  
Initial Rise ◽  
Male And Female Rats ◽  
Time Of Operation

SUMMARY The changes in plasma luteinizing hormone (LH) concentration during the first few days after ovariectomy in the rat differ according to the stage of the cycle at which the operation is performed. When carried out at oestrus there was no increase in LH concentration in the first 4 days. After operation at metoestrus the concentration was increased at 3 days but not earlier. Ovariectomy at dioestrus resulted in an immediate increase after 8 h, a subsequent fall, though not to basal levels, and a fairly steady rise thereafter. Ovariectomy at pro-oestrus produced a very large initial rise in plasma LH which probably represents an accelerated release of the ovulatory surge of LH rather than a specific response to ovariectomy. At 24 h after ovariectomy at pro-oestrus levels were below normal and did not increase again for a further 3 days. In contrast, male rats showed a rapid and sustained rise in plasma LH concentration after castration. It is suggested that the different patterns seen in the female may be related to the time that elapsed since the hypothalamo—pituitary system was exposed to high levels of circulating oestradiol. The changes in plasma LH concentration observed after ovariectomy in neonatally androgen-treated rats, rats in persistent oestrus due to exposure to constant light, and rats in early pregnancy are consistent with this hypothesis. Differing responses to the administration of sodium pentobarbitone between male and female rats even 21 days after gonadectomy suggest that there may also be differences in this negative feedback system between the two sexes that are independent of the nature of the gonadal steroid secreted.

scholarly journals STIM1/Orai1 contributes to sex differences in vascular responses to calcium in spontaneously hypertensive rats

2011 ◽  
Vol 122 (5) ◽  
pp. 215-226 ◽  
Author(s):  
Fernanda R. C. Giachini ◽  
Victor V. Lima ◽  
Fernando P. Filgueira ◽  
Anne M. Dorrance ◽  
Maria Helena C. Carvalho ◽  
...  
Keyword(s):  
Sex Differences ◽  
Neutralizing Antibodies ◽  
Spontaneously Hypertensive Rats ◽  
Female Rats ◽  
Hypertensive Rats ◽  
Vascular Protection ◽  
Spontaneously Hypertensive ◽  
Female Sex Hormones ◽  
Impaired Control ◽  
Wistar Kyoto

Sex differences in Ca2+-dependent signalling and homoeostasis in the vasculature of hypertensive rats are well characterized. However, sex-related differences in SOCE (store-operated Ca2+ entry) have been minimally investigated. We hypothesized that vascular protection in females, compared with males, reflects decreased Ca2+ mobilization due to diminished activation of Orai1/STIM1 (stromal interaction molecule 1). In addition, we investigated whether ovariectomy in females affects the activation of the Orai1/STIM1 pathway. Endothelium-denuded aortic rings from male and female SHRSP (stroke-prone spontaneously hypertensive rats) and WKY (Wistar–Kyoto) rats and from OVX (ovariectomized) or sham female SHRSP and WKY rats were used to functionally evaluate Ca2+ influx-induced contractions. Compared with females, aorta from male SHRSP displayed: (i) increased contraction during the Ca2+-loading period; (ii) similar transient contraction during Ca2+ release from the intracellular stores; (iii) increased activation of STIM1 and Orai1, as shown by the blockade of STIM1 and Orai1 with neutralizing antibodies, which reversed the sex differences in contraction during the Ca2+-loading period; and (iv) increased expression of STIM1 and Orai1. Additionally, we found that aortas from OVX-SHRSP showed increased contraction during the Ca2+-loading period and increased Orai1 expression, but no changes in the SR (sarcoplasmic reticulum)-buffering capacity or STIM1 expression. These findings suggest that augmented activation of STIM1/Orai1 in aortas from male SHRSP represents a mechanism that contributes to sex-related impaired control of intracellular Ca2+ levels. Furthermore, female sex hormones may negatively modulate the STIM/Orai1 pathway, contributing to vascular protection observed in female rats.

Exercise training and incidence of cerebrovascular lesions in stroke-prone spontaneously hypertensive rats

1990 ◽  
Vol 68 (3) ◽  
pp. 1080-1085 ◽  
Author(s):  
C. M. Tipton ◽  
S. McMahon ◽  
J. R. Leininger ◽  
E. L. Pauli ◽  
C. Lauber
Keyword(s):  
Exercise Training ◽  
Spontaneously Hypertensive Rats ◽  
Female Rats ◽  
Moderate Exercise ◽  
Hypertensive Rats ◽  
Cerebrovascular Lesions ◽  
Spontaneously Hypertensive ◽  
Male And Female Rats ◽  
Blood Pressures ◽  
Subjective Evidence

To assess the effects of moderate exercise [40-70% maximal oxygen uptake (VO2max)] on resting blood pressures, the presence of cerebrovascular lesions, and the life spans of stroke-prone hypertensive rats, nontrained and trained male and female rats were assigned to two experimental groups. The first (n = 48) were exercise trained after 38 days of age, whereas the second (n = 44) initiated exercise training when the animals were 134 days of age. To facilitate cerebrovascular lesions, the sodium concentrations in the rat chow and in the drinking solutions were increased. Symptoms utilized to denote the presence of cerebrovascular lesions were irritability, hyperresponsiveness, ataxia, lethargy, unwillingness to run, and combinations thereof. All brains were removed immediately after death, fixed, and evaluated grossly and microscopically for lesions. In the study with the younger animals, training was associated with a 7-9% increase in VO2max that was statistically significant only in animals with no histological evidence of cerebrovascular lesions. For the older animals, a significant 5-8% increase in VO2max was noted for animals with or without lesions. After 42 days of training for both groups, resting blood pressures for the trained groups with histological lesions were significantly lower. However, this trend did not continue, and the older trained rats appeared to have strokes earlier and to die sooner than their nontrained controls. Although 83% of the older animals had subjective evidence for a stroke before they died, the percentage of animals with lesions ranged from 42 to 58%, with the trained groups having higher percentages.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathways of bradykinin degradation in blood and plasma of normotensive and hypertensive rats

2001 ◽  
Vol 280 (5) ◽  
pp. H2182-H2188 ◽  
Author(s):  
Andreas Dendorfer ◽  
Sebastian Wolfrum ◽  
Marc Wagemann ◽  
Fatimunnisa Qadri ◽  
Peter Dominiak
Keyword(s):  
High Performance ◽  
Enzymatic Degradation ◽  
Hypertensive Rats ◽  
Angiotensin I ◽  
Spontaneously Hypertensive ◽  
Angiotensin I Converting Enzyme ◽  
Aminopeptidase P ◽  
Carboxypeptidase N ◽  
Wistar Kyoto

Kinins are vasoactive peptide hormones that can confer protection against the development of hypertension. Because their efficacy is greatly influenced by the rate of enzymatic degradation, the activities of various kininases in plasma and blood of spontaneously hypertensive rats (SHR) were compared with those in normotensive Wistar-Kyoto rats (WKY) to identify pathogenic alterations. Either plasma or whole blood was incubated with bradykinin (10 μM). Bradykinin and kinin metabolites were measured by high-performance liquid chromatography. Kininase activities were determined by cumulative inhibition of angiotensin I-converting enzyme (ACE), carboxypeptidase N (CPN), and aminopeptidase P (APP), using selective inhibitors. Plasma of WKY rats degraded bradykinin at a rate of 13.3 ± 0.94 μmol · min−1· l−1. The enzymes ACE, APP, and CPN represented 92% of this kininase activity, with relative contributions of 52, 25, and 16%, respectively. Inclusion of blood cells at physiological concentrations did not extend the activities of these plasma kininases further. No differences of kinin degradation were found between WKY and SHR. The identical conditions of kinin degradation in WKY and SHR suggest no pathogenic role of kininases in the SHR model of genetic hypertension.

scholarly journals Isolation and Quantification of Sphingosine and Sphinganine from Rat Serum Revealed Gender Differences

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 459 ◽  
Author(s):  
Graham Brogden ◽  
Diab M. Husein ◽  
Pablo Steinberg ◽  
Hassan Y. Naim
Keyword(s):  
High Performance ◽  
Gene Mutations ◽  
Female Rats ◽  
Sphingolipid Metabolism ◽  
Female Rat ◽  
Serum Samples ◽  
Fluorescence Detector ◽  
Rat Serum ◽  
Male And Female Rats ◽  
Significant Difference

Sphingolipids are an important group of lipids that play crucial roles in living cells, facilitating cell recognition, signal transduction and endocytosis. The concentration of sphingosine and some of its derivatives like sphinganine may serve as a biomarker for the diagnosis of sphingolipidoses or be used for further research into similar diseases. In this study, a sphingolipid extraction and a high resolution detection method specific for sphingosine and sphinganine was adapted and tested. Lipids were extracted from rats’ serum, coupled to o-phthalaldehyde and detected with a fluorescence detector after running through a silica gel column in a high performance liquid chromatography system. With this method, we analysed 20 male and 20 female rat serum samples and compared the concentrations of sphingosine and sphinganine. The results showed a significant difference between the sphingosine concentrations in the male and female rats. The sphingosine concentration in female rats was 805 ng/mL (standard deviation, SD ± 549), while that in males was significantly lower at (75 ng/mL (SD ± 40)). Furthermore, the sphingosine:sphinganine ratio was almost 15-fold higher in the females’ samples. The method presented here facilitates the accurate quantification of sphingosine and sphinganine concentrations down to 2.6 ng and 3.0 ng, respectively, and their ratio in small amounts of rat serum samples to study the sphingolipid metabolism and its potential modulation due to gene mutations or the effect of prevalent toxins.

scholarly journals Gastrin, Histamine Prostaglandin: Indicators for assessing efficacy of cimetidine, Omeprazole and Ranitidine in Gastric Ulcer Treatment

2018 ◽  
Vol 5 (2) ◽  
pp. 5-12
Author(s):  
Jimmy Etukudo Okon ◽  
Gideon Umezuruike Egesie
Keyword(s):  
Gastric Ulcer ◽  
High Performance ◽  
Female Rats ◽  
Albino Rats ◽  
Radical Cure ◽  
Male And Female ◽  
Ulcer Disease ◽  
Male And Female Rats ◽  
Significant Difference ◽  
Organ Specific

Background and Objectives: There is increase prevalence of gastric ulcer in the society, but the drugs that are sensitive for radical cure are not screened with physiologic markers such which affect proper management of the disease. The objective of the study is to relate various sources or organ specific templates: gastrin, histamine and prostaglandin relating with the disease in evaluating the potencies of cimetidine, ranitidine and omeprazole for best choice of the drugs in gastric ulcer disease treatment.Material and Methods: Plasma, gastric and antral prostaglandins, histamine and gastrin levels were studied in ninety-six (96), male and female Swiss albino rats for 28 days, using high performance liquid chromatography.Results: Male and female rats with gastric ulcer treated with cimetidine, omepraszole and ranitidine showed no significant difference (P>0.5) in gastrin and the drug groups in plasma, gastric and antral concentrations. But, there was significant difference (P<0.05) in histamine levels between cimetidine, omeprazole and ranitidine in their gastric and plasma concentration. There was no significant difference (P>0.05) in prostaglandin values between cimetidine, omeprazole and ranitidine. Also there was no significant difference (P>0.05) in gastric and plasma levels of gastrin, histamine and prostaglandin between 7, 14, 21 and 28 days treatment period. But, there was significant difference (P<0.05) in antral concentration of gastrin, histamines and prostaglandin between the drug groups. However, there was no significant difference (P>0.05) in antral gastrin between male and female rats in cimetidine and ranitidine treatment. The three drugs were associated with high levels of gastrin, histamine, low prostaglandin though cimetidine showed higher concentration of prostaglandin.Conclusion: It is concluded that gastrin, histamine and prostaglandin are sensitive indicators in evaluating anti-ulcerogenic drugs efficacies.Janaki Medical College Journal of Medical Sciences (2017) Vol. 5(2): 5-12

Acute exercise and gender alter cardiac autonomic tonus differently in hypertensive and normotensive rats

1998 ◽  
Vol 274 (2) ◽  
pp. R510-R516 ◽  
Author(s):  
Margaret P. Chandler ◽  
Stephen E. Dicarlo
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Acute Exercise ◽  
Female Rats ◽  
Male Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Cardiac Autonomic Regulation ◽  
Before And After ◽  
Wistar Kyoto ◽  
And Gender

Arterial pressure (AP), heart rate (HR), cardiac sympathetic tonus (ST), and parasympathetic tonus (PT) were determined in spontaneously hypertensive rats (SHR, 8 male and 8 female) and Wistar-Kyoto normotensive rats (WKY, 8 male and 12 female) before and after acute exercise. Before exercise, hypertensive rats (regardless of gender) had an increased ST (+15 beats/min), increased resting HR (+12 beats/min), and decreased PT (−11 beats/min). Similarly, female rats (regardless of strain) also had an increased ST (+15 beats/min), increased resting HR (+39 beats/min), and decreased PT (−14 beats/min). Hypertensive rats had a significant reduction in AP (−17 ± 3 mmHg), ST (−26 beats/min), PT (−7 beats/min), and HR (−14 beats/min) after exercise. In contrast, AP was not reduced in normotensive rats and ST (+18 beats/min) and HR (+42 beats/min) were increased in female normotensive rats after exercise. However, male normotensive rats had a postexercise reduction in ST (−14 beats/min) and HR (−19 beats/min). In summary, AP, ST, and resting HR were higher whereas PT was lower in hypertensive vs. normotensive rats. Furthermore, females had a higher resting HR, intrinsic HR, and ST and lower PT than male rats. These data demonstrate that gender and the resting level of AP influence cardiac autonomic regulation.

Sign in / Sign up

Export Citation Format

Share Document