scholarly journals Cyclic Changes in the Oxygen Consumption of the Aorta in Female Rats

1964 ◽  
Vol 14 (4) ◽  
pp. 364-366 ◽  
Author(s):  
M. R. MALINOW ◽  
J. A. MOGUILEVSKY ◽  
L. GERSCHENSON
Keyword(s):  
Oxygen Consumption ◽  
Female Rats ◽  
Cyclic Changes

Tolerance of estrogen-treated rats to acute cold exposure

1979 ◽  
Vol 47 (1) ◽  
pp. 59-66 ◽  
Author(s):  
M. J. Fregly ◽  
D. L. Kelleher ◽  
D. J. Black
Keyword(s):  
Oxygen Consumption ◽  
Cold Exposure ◽  
Previous Experiment ◽  
Female Rats ◽  
Control Group ◽  
Maximal Rate ◽  
Acute Cold Exposure ◽  
Exposure To Cold ◽  
Rate Of Oxygen Consumption ◽  
Rate Of Cooling

Female rats treated chronically with ethynylestradiol (36 micrograms/kg per day) alone, and in combination with the progestational agent, norethynodrel (253 micrograms/kg per day), cooled significantly faster than controls when lightly restrained and exposed to air at 5 degrees C. Rate of cooling of rats given only norethynodrel was similar to that of the control group. In other studies, rate of oxygen consumption was determined for all groups during acute exposure to cold (14 degrees C). All estrogen-treated groups achieved the same maximal rate of oxygen consumption as control and norethynodrel-treated groups during cold exposure, but cooled significantly faster. Two groups of female rats were treated chronically with ethynylestradiol at two separate doses (36 and 61 micrograms/kg per day). An untreated group served as controls. Rate of oxygen consumption of all animals were measured during restraint and exposure to cold (18 degrees C). The estrogen-treated groups again achieved the same maximal rate of oxygen consumption as the control group, but also cooled significantly faster despite the fact that the cold stress was less severe than in the previous experiment. That estrogen-treated rats cooled faster than controls in both studies despite achieving a maximal rate of heat production which did not differ from controls suggests that reduced cold tolerance of estrogen-treated rats may be related to increased heat loss.

Effect of age and gender on thermoregulation

1989 ◽  
Vol 257 (4) ◽  
pp. R700-R704 ◽  
Author(s):  
R. B. McDonald ◽  
C. Day ◽  
K. Carlson ◽  
J. S. Stern ◽  
B. A. Horwitz
Keyword(s):  
Oxygen Consumption ◽  
Cold Exposure ◽  
Female Rats ◽  
Male Rats ◽  
Differential Heat ◽  
Independent Basis ◽  
Male And Female Rats ◽  
Brown Adipose ◽  
And Gender ◽  
Colonic Temperature

Previous investigations have shown that during cold exposure 24-mo-old male Fischer 344 (F344) rats do not thermoregulate as well as do 12-mo-old animals. To determine if this deficiency also occurs in female rats, we measured oxygen consumption (thermogenesis) and colonic temperature of male and female rats 5, 23, and 27 mo of age at rest and during 6 h of exposure to 6 degrees C. In addition, nonshivering thermogenesis (NST) was evaluated from the capacity of brown adipose tissue (BAT) mitochondria isolated from cold-exposed rats to bind guanosine 5'-diphosphate (GDP). Neither age nor gender had a significant effect on resting or cold-exposed oxygen consumption expressed on a mass-independent basis (l/kg body mass0.67) or on a lean body mass independent basis (l/kg lean body mass0.67). The drop in colonic temperature in response to cold was greater in the male rats. However, females exhibited increased BAT mass and relatively constant GDP binding with advancing age, whereas males showed decreased mass and GDP binding. Although the data suggest greater NST capacity in the female rats, rates of cold-induced oxygen consumption were similar in older female vs. male rats. Taken together, our data indicate that gender has a significant impact on thermoregulation and that, under the cold exposure conditions of the study, this effect involves differential heat conservation rather than heat production.

scholarly journals Disruption of estradiol regulation of orexin neurons: a novel mechanism in excessive ventilatory response to CO2 inhalation in a female rat model of panic disorder

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Luana Tenorio-Lopes ◽  
Stéphanie Fournier ◽  
Mathilde S. Henry ◽  
Frédéric Bretzner ◽  
Richard Kinkead
Keyword(s):  
Panic Disorder ◽  
Hormonal Regulation ◽  
Maternal Separation ◽  
Ventilatory Response ◽  
Female Rats ◽  
Female Rat ◽  
Estrus Cycle ◽  
Whole Cell Patch Clamp ◽  
Basal Plasma ◽  
Cyclic Changes

AbstractPanic disorder (PD) is ~2 times more frequent in women. An excessive ventilatory response to CO2 inhalation is more likely during the premenstrual phase. While ovarian hormones appear important in the pathophysiology of PD, their role remains poorly understood as female animals are rarely used in pre-clinical studies. Using neonatal maternal separation (NMS) to induce a “PD-like” respiratory phenotype, we tested the hypothesis that NMS disrupts hormonal regulation of the ventilatory response to CO2 in female rats. We then determined whether NMS attenuates the inhibitory actions of 17-β estradiol (E2) on orexin neurons (ORX). Pups were exposed to NMS (3 h/day; postnatal day 3–12). The ventilatory response to CO2-inhalation was tested before puberty, across the estrus cycle, and following ovariectomy. Plasma E2 and hypothalamic ORXA were measured. The effect of an ORX1 antagonist (SB334867; 15 mg/kg) on the CO2 response was tested. Excitatory postsynaptic currents (EPSCs) were recorded from ORX neurons using whole-cell patch-clamp. NMS-related increase in the CO2 response was observed only when ovaries were functional; the largest ventilation was observed during proestrus. SB334867 blocked this effect. NMS augmented levels of ORXA in hypothalamus extracts. EPSC frequency varied according to basal plasma E2 levels across the estrus cycle in controls but not NMS. NMS reproduces developmental and cyclic changes of respiratory manifestations of PD. NMS disrupts the inhibitory actions of E2 on the respiratory network. Impaired E2-related inhibition of ORX neurons during proestrus is a novel mechanism in respiratory manifestations of PD in females.

Dextromethorphan affects ventilation differently in male and female rats

1996 ◽  
Vol 81 (5) ◽  
pp. 1911-1916 ◽  
Author(s):  
Evelyn H. Schlenker
Keyword(s):  
Oxygen Consumption ◽  
Aspartic Acid ◽  
Subcutaneous Administration ◽  
Female Rats ◽  
Male Rats ◽  
Male And Female ◽  
Time Points ◽  
Specific Effects ◽  
Male And Female Rats ◽  
Gender Specific

Schlenker, Evelyn H. Dextromethorphan affects ventilation differently in male and female rats. J. Appl. Physiol. 81(5): 1911–1916, 1996.—Subcutaneous administration of aspartic acid results in a long-lasting but reversible depression of ventilation in male but not in female rats. Aspartic acid acts on N-methyl-d-aspartate receptors. The present study tested the hypothesis that a noncompetitive N-methyl-d-aspartate-receptor antagonist, dextromethorphan (Dex), would depress ventilation in female rats and stimulate it in male rats. Moreover, Dex administered prior to aspartic acid should prevent the aspartic acid-induced depression of ventilation in male rats. In female rats, Dex caused a 30% depression of ventilation relative to saline at 5 and 10 mg/kg ( P < 0.01) but not at the highest dose (20 mg/kg). In male rats, Dex had no effect on ventilation. At a dose of 20 mg/kg, Dex depressed oxygen consumption to 50% of the saline value at all time points in female rats ( P < 0.001) and in male rats 45 and 60 min after administration. The time points when Dex depressed ventilation and oxygen consumption were different in female rats, suggesting that the depression of ventilation was not the result of a depression in oxygen consumption. During a hypercapnic challenge (7% CO2), female rats treated with 5 and 10 mg/kg of Dex exhibited a smaller increase in ventilatory response relative to saline treatment. At a dose of 20 mg/kg, the hypercapnic responsiveness of male rats was markedly stimulated (85.8 ± 8.95 ml/min) relative to saline (50.6 ± 9.14 ml/min; P < 0.001). Finally, Dex administered before aspartic acid prevented the aspartic acid-induced depression of ventilation in male rats. Thus, in rats, Dex has gender-specific effects on ventilation and these effects are not associated with changes in oxygen consumption.

Modern aspects of biological modeling of sexual development disorders

2021 ◽  
pp. 128-136
Author(s):  
Ю.Ю. Чеботарева ◽  
В.Г. Овсянников ◽  
М.А. Родина ◽  
И.В. Подгорный ◽  
М.Я. Хутиева
Keyword(s):  
Sexual Development ◽  
Experimental Studies ◽  
Female Rats ◽  
Biological Modeling ◽  
Reproductive Disorders ◽  
Hormone Synthesis ◽  
Brain Neurotransmitter ◽  
Important Direction ◽  
Cyclic Changes ◽  
The Brain

Введение. Изучение механизмов развития репродуктивных нарушений в условиях эксперимента на крысах является одним из важных направлений современной патофизиологии. Крыса имеет функционирующий эстральный цикл, трехнедельную гестацию и гемохориальный тип плацентации. На циклических изменениях в яичниках и эпителии влагалища крысы базируется биологическое моделирование эндокринной гинекологической патологии. В настоящее время интерес представляет разработка экспериментальной модели нарушения полового созревания в периоде детства. Нарушение полового созревания может приводить к различным патологическим изменениям в сфере репродуктивного здоровья в будущем, актуальность данной проблемы очевидна. Цель работы - изучение современных аспектов моделирования преждевременного полового созревания у девочек. Методика. Анализ современных отечественных и зарубежных работ, касающихся механизмов преждевременного полового созревания и исследований в области моделирования данной патологии в экспериментах на крысах. Результаты. Преждевременное половое созревание у девочек - нарушение, проявляющееся развитием одного или комплекса признаков половой зрелости до 7 летнего возраста. Детерминация полового развития связана с особенностью генетических и эпигенетических факторов. К последним традиционно относят характер питания, стресс как адаптационную реакцию, интегрированную с активацией гормонопоэза. Фактор питания связан с функционированием гормонов жировой ткани, включая лептин, грелин, эффектами инсулиноподобного фактора роста. В ряде экспериментальных исследований, связанных с воздействием факторов питания, стресса и световой дезадаптации на репродуктивную систему животного, доказано значимое влияние последней на нейромедиаторные системы мозга. Наименее изученными в механизме преждевременного полового созревания остаются вопросы нейроэндокринной регуляции гонадной оси системой KISS/KISS1R. Продолжение изучения ассоциации изменения профиля нейромедиаторов моноаминового ряда и динамики кисспептина в эксперименте на крысах способно расширить представление о механизмах половой дифференцировки мозга и транслировать полученные данные в клиническую практику, связанную с обследованием девочек с преждевременным половым созреванием. Заключение. В связи с малой распространенностью и ограниченностью представлений о патогенезе преждевременного полового созревания, данная проблема требует детального изучения. Необходимо дальнейшее изучение патогенетических основ данной патологии в условиях биологического моделирования на самках крыс раннего возраста. Introduction. Studying pathogenetic mechanisms responsible for development of reproductive disorders in rat models is an important direction of modern pathophysiology. The rat has a functioning estrous cycle, a three-week gestation, and a hemochorial placentation. Biological modeling of endocrine gynecological pathology is based on cyclic changes in the ovaries and in the epithelium of the rat vagina. Currently, the development of an experimental model of puberty disorders in childhood is of interest. Premature puberty can lead to various pathological changes in future reproductive health. The relevance of this problem is obvious. The aim of this work was to study modern aspects of modeling premature puberty in girls. Method. Modern domestic and foreign reviews on the mechanism of premature puberty and studies of modeling this pathology in experiments on rats were analyzed. Results. Premature puberty in girls is a disorder manifested by the development of one or all signs of puberty as early as before the age of 7 yrs. Sexual development is associated with characteristic roles of genetic and epigenetic factors. The latter traditionally include nutrition and stress as an adaptive reaction integrated with the activation of hormone synthesis. The nutrition factor is related with the functioning of adipose tissue hormones, including leptin, ghrelin, and the effects of insulin-like growth factor. A number of experimental studies on rats addressing effects of nutrition, stress, and light maladaptation on the reproductive system have demonstrated its significant effect on brain neurotransmitter systems. Regarding the mechanism of premature puberty, the least studied issue is the neuroendocrine regulation of the gonadal axis by the KISS/KISS1R system. Continuing study of the association between changes in the profile of monoamine neurotransmitters and the dynamics of kisspeptin in experiments on rats can expand understanding of sexual differentiation mechanisms in the brain. The obtained data can be translated into clinical practice for the management of premature puberty in girls. Conclusion. Due to the rare prevalence of premature puberty and insufficient data on its pathogenesis, this problem requires detailed study. It is necessary to further study the mechanism of this pathology by biological modeling on female rats at an early age.

The effect of excess vitamin A on the oxygen consumption of young female rats

1962 ◽  
Vol 151 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Myra M. Sampson ◽  
Esther Carpenter ◽  
Roland Wight
Keyword(s):  
Oxygen Consumption ◽  
Vitamin A ◽  
Young Female ◽  
Female Rats

Enhanced thermogenesis during recovery from diet-induced weight gain in the rat

1996 ◽  
Vol 271 (5) ◽  
pp. R1380-R1387 ◽  
Author(s):  
N. G. Almeida ◽  
D. A. Levitsky ◽  
B. Strupp
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Control Diet ◽  
Female Rats ◽  
High Fat ◽  
Serum T3 ◽  
Diet Control ◽  
The Stability ◽  
Thermogenic Response

The present study examined the contribution of energy expenditure to the recovery of body weight after a period of overfeeding. Three groups of 2-mo-old female rats (n = 24) were fed, respectively, a 10% (wt/wt)-fat diet (control), a 35% (wt/wt)-fat diet (high fat) or were force fed 130% of the control diet (tube fed). After 30 days, all groups received the control diet for 18 days of recovery. Both overfeeding protocols significantly increased weight above control levels. This difference disappeared after 7 days of recovery. Increases in resting oxygen consumption, serum 3,5,3'-triiodothyronine (T3) levels, and the thermogenic response to norepinephrine were observed at the end of overfeeding. Serum T3 and resting oxygen consumption returned to control levels by day 3 of recovery from overfeeding, whereas the thermogenic response to norepinephrine required 9 days to recover. Whereas total energy expenditure was not significantly elevated during overfeeding, significant increases of 9.6 and 13.9% were observed in the formerly high-fat and tube-fed animals, respectively, during recovery. These data indicate that changes in energy expenditure play an important role in maintaining the stability of body weight.

THE EFFECT OF AGE, SEX, AND PREVIOUS PREGNANCY ON THE OXYGEN UPTAKE OF RAT MAMMARY TISSUE

1952 ◽  
Vol 30 (1) ◽  
pp. 14-17
Author(s):  
Jules Tuba ◽  
M. Shirley Fraser
Keyword(s):  
Oxygen Consumption ◽  
Breast Tissue ◽  
Female Rats ◽  
Mammary Tissue ◽  
Previous Pregnancy ◽  
Consumption Values ◽  
Group 12 ◽  
History Of ◽  
Normal Rat ◽  
Effect Of Age

The effect of age, sex, and breeding on oxygen consumption and response to p-phenylenediamine of normal rat mammary tissue has been studied. Oxygen consumption values [Formula: see text] are significantly higher for breeder females than for virgin females or males. The endogenous oxygen consumption by breast tissue of virgin rats more closely resembles that of males than of breeder females. There is a significant lowering of [Formula: see text] with age in all the animals. Oxygen consumption in the presence of p-phenylenediamine [Formula: see text] is not significantly different for mammary tissue of males and breeders of the youngest age group (12–25 weeks) but it is higher for virgins of the same age. A highly significant fall in [Formula: see text] to approximately equal levels appears at a comparatively early age (30–50 weeks) in males and virgins, but this does not occur in the breeder female rats until the ability to reproduce has diminished or ceased (50 weeks and over). Reserves of the cytochrome system [Formula: see text] are lower in breeders than in males or virgins and are decreased by age in the latter two groups. These studies indicate the importance of considering age, sex, and breeding history of animals used for mammary tissue respiratory studies.

scholarly journals Physiology and behaviour of free-swimming Atlantic cod (Gadus morhua) facing fluctuating temperature conditions

1995 ◽  
Vol 198 (1) ◽  
pp. 49-60 ◽  
Author(s):  
G Claireaux ◽  
D Webber ◽  
S Kerr ◽  
R Boutilier
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Water Column ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Free Swimming ◽  
Vertical Movements ◽  
Temperature Conditions ◽  
Cyclic Changes ◽  
Thermoregulatory Behaviour

Atlantic cod (Gadus morhua L.), acclimated to 5 &deg;C, were equipped with ultrasonic transmitters which allowed the continuous monitoring of their vertical movements and heart rate. Fish were then placed in a 125 m3 tower tank in which the various thermal conditions they encounter in their natural environment were reproduced. Physiological and behavioural responses of cod were followed in parallel to the induced environmental changes. The experimental conditions studied in the tower tank were also reproduced in a swimming respirometer, where oxygen consumption and heart rate could be monitored within the activity range of a free-swimming animal. In a homogeneous water column, a rise in temperature induced marked increases in fish swimming activity, heart rate and heart beat-to-beat variability. In a thermally stratified environment, voluntary activity also increased when the thermal structure of the water column was altered, though no temperature-dependent changes in heart rate were observed. In this case, fish avoided the new temperature conditions, exhibiting distinct thermoregulatory behaviour. Stratification of the water column also prompted daily cyclic changes in fish distribution, animals tending to be in deeper and colder water layers during the day and in shallower and warmer layers at night. Respirometry experiments revealed that the thermoregulatory behaviour observed in free-ranging fish was probably driven by the energetic expedient of maintaining the physiological status quo &shy; i.e. avoiding bioenergically costly reacclimation processes. Indeed, acute temperature increases or decreases of 2.5 &deg;C led to marked differences in oxygen consumption, with metabolic rate changes of 15 and 30 %, respectively. The persistent linear relationship between heart rate and oxygen consumption allowed us to estimate, from the heart rate recorded in free-swimming fish, the entire range of metabolic responses that cod underwent voluntarily while experiencing a thermally stratified water column. The most profound metabolic effect, however, was observed with feeding, when oxygen consumption increased by as much as 80 %, resulting in an estimated 90 % reduction in their subsequent scope for activity.

Effect of catecholamines on respiration of cerebral cortex and hypothalamus in female rats

1964 ◽  
Vol 207 (3) ◽  
pp. 733-735 ◽  
Author(s):  
Jaime Alberto Moguilevsky ◽  
Jose M. Trifaró ◽  
Virgilio G. Foglia ◽  
Omar Schiaffini
Keyword(s):  
Cerebral Cortex ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Respiratory Activity ◽  
Female Rats ◽  
Sexual Cycle ◽  
Oxidative Activity ◽  
Significant Elevation ◽  
Catecholamine Levels

Epinephrine and norepinephrine in vitro produced a significant elevation in the oxygen uptake of hypothalamus in diestrus rats. No changes were observed in the respiratory activity of cerebral cortex and hypothalamus during the estrus. An increase in the oxygen consumption of diestrus hypothalamus was obtained by the injection of pheniprazine; reserpine decreases the oxidative activity of cerebral cortex during diestrus and that of the hypothalamus during the estrus. It is suggested that the changes reported herein are related to modifications of the catecholamine levels in the hypothalamus during the sexual cycle.

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