Selected Contribution: Time-dependent hypoxic respiratory responses in female rats are influenced by age and by the estrus cycle

2001 ◽  
Vol 91 (6) ◽  
pp. 2831-2838 ◽  
Author(s):  
A. G. Zabka ◽  
M. Behan ◽  
G. S. Mitchell
Keyword(s):  
Time Dependent ◽  
Female Rats ◽  
Male Rats ◽  
Estrus Cycle ◽  
Sprague Dawley ◽  
Middle Aged ◽  
Age And Gender ◽  
Gender Influence ◽  
And Gender ◽  
Respiratory Responses

Age affects time-dependent respiratory responses to episodic hypoxia in male rats, particularly long-term facilitation (LTF), a serotonin-dependent respiratory “memory” [Zabka AG, Behan M, and Mitchell GS, J Physiol (Lond) 531: 509, 2001]. Because age and gender influence serotonergic function, we tested the hypotheses that the short-term hypoxic response (STHR), posthypoxia frequency decline (PHFD) and LTF of phrenic and hypoglossal (XII) motor output change with age and stage of the estrus cycle in female rats. Young (3–4 mo) and middle-aged (13 mo) female Sprague-Dawley rats were anesthetized, paralyzed, vagotomized, and ventilated. STHR was measured during and PHFD after the first of three 5-min episodes of isocapnic hypoxia (arterial Po 2 35–45 Torr). LTF was assessed 60 min postepisodic hypoxia. Phrenic and XII STHR increased with age ( P < 0.05). PHFD was unaffected by age or gender. Phrenic LTF increased with age in both estrus and diestrus ( P < 0.05), whereas XII LTF increased in middle-aged female rats during diestrus only. Age and gender influence time-dependent hypoxic phrenic and XII responses in a complex manner.

Daily exercise and gender influence postexercise cardiac autonomic responses in hypertensive rats

1997 ◽  
Vol 272 (3) ◽  
pp. H1412-H1418 ◽  
Author(s):  
Y. Chen ◽  
M. P. Chandler ◽  
S. E. DiCarlo
Keyword(s):  
Acute Exercise ◽  
Female Rats ◽  
Male Rats ◽  
Autonomic Response ◽  
Hypertensive Rats ◽  
Experimental Conditions ◽  
Autonomic Responses ◽  
Gender Influence ◽  
Single Bout ◽  
And Gender

The influence of daily spontaneous running (DSR) and gender on postexercise cardiac autonomic responses was examined in spontaneously hypertensive rats. Rats were weaned at 4-5 wk of age and were randomly assigned to a sedentary (7 males and 6 females) or DSR (7 males and 8 females) group. After 8 weeks of DSR or sedentary control, rats were chronically instrumented with arterial and venous catheters. After 5 days of recovery, cardiac sympathetic (ST) and parasympathetic tonus (PT) were determined (by the response of heart rate to receptor antagonists) on alternate days under two experimental conditions: no exercise and postexercise. After a single bout of dynamic treadmill exercise (12 m/min, 10% grade for 40 min) ST was reduced (P < 0.05) (male sedentary: no exercise 45 +/- 4 vs. postexercise 28 +/- 3 beats/min; female sedentary: no exercise 69 +/- 10 vs. postexercise 37 +/- 7 beats/ min). PT was also altered after exercise (male sedentary: no exercise -31 +/- 4 vs. postexercise -11 +/- 2 beats/min; female sedentary: no exercise -5 +/- 4 vs. postexercise 7 +/- 4 beats/min). After DSR, ST was reduced (male sedentary 45 +/- 4 vs. DSR 22 +/- 3 beats/min; female sedentary 69 +/- 10 vs. DSR 36 +/- 4 beats/min) (P < 0.05). Finally, male rats had a lower ST and higher PT than female rats. These results demonstrate that 1) ST was reduced after a single bout of dynamic exercise; 2) ST was reduced after DSR; 3) the autonomic response to acute exercise was attenuated after DSR; and 4) there was a gender influence on the cardiac autonomic function.

Daily exercise and gender influence arterial baroreflex regulation of heart rate and nerve activity

1996 ◽  
Vol 271 (5) ◽  
pp. H1840-H1848 ◽  
Author(s):  
C. Y. Chen ◽  
S. E. DiCarlo
Keyword(s):  
Heart Rate ◽  
Female Rats ◽  
Male Rats ◽  
Heart Weight ◽  
Arterial Baroreflex ◽  
Nerve Activity ◽  
Male And Female ◽  
Gender Influence ◽  
Male And Female Rats ◽  
And Gender

The influence of daily spontaneous running (DSR) and gender on the arterial baroreflex regulation of heart rate (HR) and lumbar sympathetic nerve activity (LSNA) was examined in 13 male [7 sedentary (SED) and 6 DSR] and 12 female (6 SED and 6 DSR) Sprague-Dawley rats. After 8-9 wk of DSR or SED control, all animals were chronically instrumented with right femoral venous and left carotid arterial catheters and electrodes around the lumbar sympathetic trunk. DSR resulted in an increase in heart weight-to-body weight ratio (P = 0.001) in male and female rats and resting bradycardia in male rats (P = 0.001). Arterial baroreflex function was examined by ramp increases (1.25 +/- 0.07 mmHg/s) and decreases (1.47 mmHg/s) in arterial pressure. DSR attenuated the arterial baroreflex regulation of LSNA in a similar manner in female and male rats. DSR reduced the range (32 and 29% for female and male rats, respectively), maximum (26 and 21% for female and male rats, respectively), and maximum gain (Gmax; 46 and 17% for female and male rats, respectively). In contrast, there was a gender influence on the arterial baroreflex regulation of HR. For example, SED female rats had a higher Gmax (40%) than SED male rats. Furthermore, DSR altered the arterial baroreflex regulation of HR differently in male and female rats. DSR female rats had a reduced Gmax (38%), range (25%), and maximum (12%), whereas DSR male rats had a reduced maximum (17%) and minimum (23%). These results demonstrate that DSR attenuated the arterial baroreflex regulation of LSNA in a similar manner in female and male rats. In contrast, DSR altered the arterial baroreflex regulation of HR differently in female and male rats.

scholarly journals Possible interaction of gender and age on human swallowing behavior

2011 ◽  
Vol 48 (3) ◽  
pp. 195-198 ◽  
Author(s):  
Roberto Oliveira Dantas ◽  
Leda Maria Tavares Alves ◽  
Carla Manfredi dos Santos ◽  
Rachel de Aguiar Cassiani
Keyword(s):  
Older Women ◽  
Healthy Subjects ◽  
Middle Aged ◽  
Age And Gender ◽  
Gender Influence ◽  
Gender And Age ◽  
Older Subjects ◽  
Aged Subjects ◽  
And Gender ◽  
Effect Of Age

CONTEXT: The swallowing behavior is affected by age and possibly by gender. However, the interaction of the effects of age and gender on swallowing is not completely known. OBJECTIVES: To evaluate the possibility of interaction of gender and age on human swallowing behavior. METHOD: Swallowing was evaluated in 89 healthy subjects by the water swallowing test, 43 men and 46 women aged 20-40 years (younger, n = 38), 41-60 years (middle-aged, n = 31) and 61-80 years (older, n = 20). Each subject ingested in triplicate 50 mL of water while precisely timed and the number of swallows needed to ingest all the volume was counted. RESULTS: The interval between swallows was shorter and the volume in each swallow was smaller in women compared to men. In older subjects the time to ingest the 50 mL of water was longer, the interval between swallows was longer, and swallowing flow and volume in each swallow were smaller than in younger and middle-aged subjects. The swallowing flow was lower in women compared to men in younger subjects. The volume of each swallow was smaller in women than in men in younger and middle-aged subjects. There was no difference in swallowing flow and volume between older men and older women. CONCLUSION: Age and gender influence swallowing behavior, with the effect of gender being more evident in younger subjects and the effect of age being more evident in men.

Age- and gender-related changes in glucose homeostasis in glucocorticoid-treated rats

2014 ◽  
Vol 92 (10) ◽  
pp. 867-878 ◽  
Author(s):  
Cristiane dos Santos ◽  
Francielle Batista D. Ferreira ◽  
Luiz M. Gonçalves-Neto ◽  
Sebastião Roberto Taboga ◽  
Antonio Carlos Boschero ◽  
...  
Keyword(s):  
Body Mass ◽  
Glucose Intolerance ◽  
Glucose Homeostasis ◽  
Cell Mass ◽  
Female Rats ◽  
Male Rats ◽  
Dexamethasone Treatment ◽  
Age And Gender ◽  
Male And Female Rats ◽  
And Gender

The disruption to glucose homeostasis upon glucocorticoid (GC) treatment in adult male rats has not been fully characterized in older rats or in females. Thus, we evaluated the age- and gender-related changes in glucose homeostasis in GC-treated rats. We injected male and female rats at 3 months and 12 months of age with either dexamethasone (1.0 mg/kg body mass, intraperitoneally) or saline, daily for 5 days. All of the GC-treated rats had decreased body mass and food intake, and adrenal hypotrophy. Increased glycemia was observed in all of the GC-treated groups and only the 3-month-old female rats were not glucose intolerant. Dexamethasone treatment resulted in hyperinsulinemia and hypertriacylglyceridemia in all of the GC-treated rats. The glucose-stimulated insulin secretion (GSIS) was higher in all of the dexamethasone-treated animals, but it was less pronounced in the older animals. The β-cell mass was increased in the younger male rats treated with dexamethasone. We conclude that dexamethasone treatment induces glucose intolerance in both the 3- and 12-month-old male rats as well as hyperinsulinemia and augmented GSIS. Three-month-old female rats are protected from glucose intolerance caused by GC, whereas 12-month-old female rats developed the same complications that were present in 3- and 12-month-old male rats.

scholarly journals Age-Related Effects on Right Femoral Bone of Male Wistar Rats: A Morphometric and Biomechanical Study

2021 ◽  
Author(s):  
Sheila Martins Puelker ◽  
Sonia Regina Ribeiro de Castro ◽  
Romeu Rodrigues de Souza ◽  
Laura Beatriz Mesiano Maifrino ◽  
Ricardo Aparecido Baptista Nucci ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Wistar Rats ◽  
Female Rats ◽  
Male Rats ◽  
Aged Rats ◽  
Femoral Bone ◽  
Middle Aged ◽  
Left Femur ◽  
Bone Stiffness ◽  
The Right

Abstract Introduction Study of the variations of bone characteristics with age in different animal models is important to design musculoskeletal studies. Thus, this study aimed to evaluate the bone mass, dimensions, and biomechanical parameters of the femur in young, middle-aged, and aged Wistar rats. Materials and Methods Thirty male rats (Rattus norvegicus) were divided in three groups (n = 10 per group)—3-month-old young rats, 12-month-old middle-aged rats, and 18-months-old aged rats. The right femurs were subjected sequentially to morphometric study (bone weight, cortical thickness) and biomechanical tests (maximum resistance strength and bone stiffness). Results We observed a significant increase in femur histological (cortical thickness) and biomechanical (maximum strength and bone stiffness) parameters with aging when compared with young animals. Conclusions With the advancing age, the right femoral bone of middle-aged and old animals had greater variations when compared with young animals. However, further studies with the aid of a comparison between right and left femur and other long bones in both male and female rats are needed to corroborate with our findings.

Selected Contribution: Chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats

2003 ◽  
Vol 95 (6) ◽  
pp. 2614-2623 ◽  
Author(s):  
A. G. Zabka ◽  
G. S. Mitchell ◽  
E. B. Olson ◽  
M. Behan
Keyword(s):  
Intermittent Hypoxia ◽  
Young Female ◽  
Time Dependent ◽  
Female Rats ◽  
Chronic Intermittent Hypoxia ◽  
Middle Aged ◽  
Short Term ◽  
Hypoxic Response ◽  
Long Term Facilitation

Age and the estrus cycle affect time-dependent respiratory responses to episodic hypoxia in female rats. Respiratory long-term facilitation (LTF) is enhanced in middle-aged vs. young female rats ( 72 ). We tested the hypothesis that phrenic and hypoglossal (XII) LTF are diminished in acyclic geriatric rats when fluctuating sex hormone levels no longer establish conditions that enhance LTF. Chronic intermittent hypoxia (CIH) enhances LTF ( 41 ); thus we further predicted that CIH would restore LTF in geriatric female rats. LTF was measured in young (3-4 mo) and geriatric (20-22 mo) female Sasco Sprague-Dawley rats and in a group of geriatric rats exposed to 1 wk of nocturnal CIH (11 vs. 21% O2 at 5-min intervals, 12 h/night). In anesthetized, paralyzed, vagotomized, and ventilated rats, time-dependent hypoxic phrenic and XII responses were assessed. The short-term hypoxic response was measured during the first of three 5-min episodes of isocapnic hypoxia (arterial Po2 35-45 Torr). LTF was assessed 15, 30, and 60 min postepisodic hypoxia. Phrenic and XII short-term hypoxic response was not different among groups, regardless of CIH treatment ( P > 0.05). LTF in geriatric female rats was smaller than previously reported for middle-aged rats but comparable to that in young female rats. CIH augmented phrenic and XII LTF to levels similar to those of middle-aged female rats without CIH ( P < 0.05). The magnitude of phrenic and XII LTF in all groups was inversely related to the ratio of progesterone to estradiol serum levels ( P < 0.05). Thus CIH and sex hormones influence the magnitude of LTF in geriatric female rats.

scholarly journals Characteristic Movement of the Ribs, Thoracic Vertebrae while Elevating the Upper Limbs - Influences of Age and Gender on Movements

2019 ◽  
Vol 13 (1) ◽  
pp. 170-176
Author(s):  
Hisayoshi Tachihara ◽  
Junichiro Hamada
Keyword(s):  
Young Group ◽  
Thoracic Vertebrae ◽  
Middle Aged ◽  
Age And Gender ◽  
Aged Group ◽  
Age Related ◽  
Significant Difference ◽  
Shoulder Disorders ◽  
Arm Elevation ◽  
And Gender

Background: The rib cage, such as the thoracic spine and ribs, influences glenohumeral mobility and the development of shoulder disorders. Objective: To evaluate movements of the ribs, thoracic vertebrae during bilateral arm elevation and to clarify the characteristic influences of age and gender. Methods: Subjects comprised 33 healthy individuals divided into a young group (10 males, 7 females; mean age, 25 years) and a middle-aged group (8 males, 8 females; mean age, 52 years). Chest CT was performed with two arm positions: arms hanging downwards; and arms elevated at 160°. Images were three-dimensionally reconstructed to evaluate rib movement, extension angle of thoracic vertebrae. Results: Maximal movement was observed at the fifth rib, and rib movement decreased with increasing distance from the fifth rib in both the groups. In males, movement of the second to fourth ribs was smaller in the middle-aged group than in the young group (p < 0.05). Movement of the first to ninth ribs was smaller in females than in males (p < 0.05). No significant difference in the extension angle of the thoracic vertebrae was found. Conclusion: Fifth rib movement is the largest among all ribs during bilateral arm elevation. Reduction of upper rib movement initially arises as an age-related degradation in males. Women exhibit less rib movement during bilateral arm elevation.

Abstract P045: Sex And Age Specific Circulating Aldosterone Changes In Transgenic Hypertensive (mRen2)27 Rats And Hannover Sprague Dawley (SD) Rats And Its Association With Blood Pressure And Cardiac Function

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Fatima Ryalat ◽  
N Cruz-Diaz ◽  
W Graham ◽  
T Gwathmey-Williams ◽  
P E Gallagher ◽  
...  
Keyword(s):  
Heart Failure ◽  
Blood Pressure ◽  
Cardiac Function ◽  
Target Organ Damage ◽  
Aging Effect ◽  
Female Rats ◽  
Male Rats ◽  
Sprague Dawley ◽  
Aldosterone Antagonists ◽  
Sd Rats

Aldosterone plays a significant role in hypertension and target organ damage. Aldosterone antagonists are used in the management of heart failure. However, neither the influence of age nor sex on aldosterone pathophysiology is well understood. We investigated the changes in circulating aldosterone with age and its association with cardiovascular function, using male and female hypertensive renin transgenic (mRen2)27 rats and SD rats at 20 and 50 weeks of age. Both male (22 ± 3 vs. 12 ± 2 ng/dL, n = 9 - 12, p < 0.05) and female (59 ± 10 vs. 23 ± 8 ng/dL, n = 6 - 10, p < 0.05) hypertensive rats had higher serum aldosterone compared with SD rats at 20 weeks of age. At 50 weeks of age, the difference persisted in the hypertensive female rats (63 ± 8 vs. SD: 33 ± 7 ng/dL, n = 6 - 7, p < 0.05), but not in the males. SD male rats have higher systolic blood pressure (SBP) as they age, and consequently develop cardiac diastolic dysfunction associated with higher aldosterone at 50 weeks compared to 20 weeks (28 ± 3 vs. 12 ± 2 ng/dL, n = 7 - 9, p < 0.05). This aging effect on aldosterone was not significant in the other groups. We showed previously that SD males treated with polyphenol rich muscadine grape extract (MGE) have lower aldosterone, less aortic stiffness and better cardiac diastolic function (E/e’) than controls at the older age; the MGE effect was not seen in (mRen2)27 males. Sex differences in aldosterone were not significant in the SD rats at either time point. However, (mRen2)27 female rats had higher aldosterone than (mRen2)27 males at both 20 weeks (59 ± 10 vs. 22 ± 3 ng/dL, n = 10 - 12, p < 0.05) and 50 weeks (63 ± 8 vs. 31 ± 7 ng/dL, n = 6 - 7, p < 0.05), despite the lack of significant differences in SBP. (mRen2)27 female rats preserve cardiac function better than males throughout their life span, while males develop indices of heart failure. Our data suggest that lower aldosterone levels in hypertensive males compared with females do not protect against the higher lifetime burden of elevated SBP and also may reflect different mechanisms controlling circulating aldosterone between sexes. In addition, data suggest a potential therapeutic effect of MGE in the management of age-associated moderate hypertension.

Sexual dimorphism in vasopressin-induced contraction of rat aorta

1991 ◽  
Vol 260 (2) ◽  
pp. H453-H458 ◽  
Author(s):  
J. N. Stallone ◽  
J. T. Crofton ◽  
L. Share
Keyword(s):  
Estrous Cycle ◽  
Vascular Reactivity ◽  
Rat Aorta ◽  
Isometric Tension ◽  
Female Rats ◽  
Male Rats ◽  
Maximal Response ◽  
Sprague Dawley ◽  
Tension Development ◽  
Sprague Dawley Rats

Previously, we reported that, in the rat, pressor responsiveness to vasopressin (VP) is higher in males than in females during most phases of the estrous cycle. To explore the role of the vasculature in this phenomenon, we examined vascular reactivity to VP in thoracic aortas of male rats and female rats during each phase of the estrous cycle. Aortic rings were prepared from age-matched male and female Sprague-Dawley rats and mounted for isometric tension recording. Maximal response of female aortas to VP (4,246 +/- 163 mg/mg ring dry wt) was more than twice (P less than 0.001) that of male aortas (1,877 +/- 215 mg/mg ring wt). Sensitivity of female aortas to VP was substantially higher (P less than 0.001) than that of male aortas (EC50: 10.9 +/- 0.7 vs. 19.0 +/- 1.6 nM, respectively). Maximal rate of tension development (dT/dtmax) during contraction with VP was nearly twofold higher (P less than 0.01) in female aortas (536 +/- 23 mg/min) than in male aortas (300 +/- 19 mg/min). Maximal response, sensitivity, and dT/dtmax of female aortas did not vary significantly during the estrous cycle. Maximal response of female aortas to phenylephrine (PE; 1,251 +/- 93 mg/mg ring wt) was half that (P less than 0.001) of male aortas (2,546 +/- 194 mg/mg ring wt); sensitivity to PE did not differ significantly (EC50: 0.33 +/- 0.02 vs. 0.38 +/- 0.06 microM, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

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