scholarly journals Effects of aging on mineralocorticoid-induced salt appetite in rats

2013 ◽  
Vol 305 (12) ◽  
pp. R1498-R1505 ◽  
Author(s):  
Robert L. Thunhorst ◽  
Terry G. Beltz ◽  
Alan Kim Johnson
Keyword(s):  
Saline Solution ◽  
Brown Norway ◽  
Salt Appetite ◽  
Aged Rats ◽  
Middle Aged ◽  
Renal Handling ◽  
Saline Preference ◽  
Old Rats ◽  
Middle Aged Adult ◽  
Effects Of Aging

This work examined the effects of age on salt appetite measured in the form of daily saline (i.e., 0.3 M NaCl) drinking in response to administration of deoxycorticosterone acetate (DOCA; 5 mg/kg body wt) using young (4 mo), “middle-aged” adult (12 mo), and old (30 mo) male Brown Norway rats. Water and sodium intakes, excretions, and balances were determined daily. The salt appetite response was age dependent with “middle-aged” rats ingesting the most saline solution followed in order by young and then old rats. While old rats drank the least saline solution, the amounts of saline ingested still were copious and comprise an unambiguous demonstration of salt appetite in old rats. Middle-aged rats had the highest saline preference ratios of the groups under baseline conditions and throughout testing consistent with an increased avidity for sodium taste. There were age differences in renal handling of water and sodium that were consistent with a renal contribution to the greater saline intakes by middle-aged rats. There was evidence of impaired renal function in old rats, but this did not account for the reduced saline intakes of the oldest rats.

scholarly journals Hypotension- and osmotically induced thirst in old Brown Norway rats

2009 ◽  
Vol 297 (1) ◽  
pp. R149-R157 ◽  
Author(s):  
Robert L. Thunhorst ◽  
Terry G. Beltz ◽  
Alan Kim Johnson
Keyword(s):  
Arterial Pressure ◽  
Brown Norway ◽  
Aged Rats ◽  
Middle Aged ◽  
Young Rats ◽  
Age Related ◽  
Cellular Dehydration ◽  
Old Rats ◽  
Middle Aged Adult ◽  
Norway Rats

Compared to young cohorts, old rats drink less water in response to several thirst-inducing stimuli. In these experiments, we characterized water drinking in response to hypotension and cellular dehydration in young (4 mo), middle-aged adult (12 mo) and old (29–30 mo) male Brown Norway rats. We injected the vasodilator, minoxidil as an intravenous bolus in a range of doses (0–20 mg/kg), so that drinking responses could be compared at equivalent reductions of arterial pressure. Old rats had greatly diminished reflex tachycardia and became significantly more hypotensive after minoxidil compared with young and middle-aged rats. When compared at equivalent reductions of arterial pressure, old rats drank one-third as much as middle-aged rats, and one-fifth as much as young rats. In addition, there were age-related deficits in drinking in response to a range of administered loads of sodium (0.15–2 M NaCl, 2 ml/100 g body wt). Urinary excretion of water and sodium in response to the loads was equivalent across ages. Both middle-aged and old rats were less able than young rats to repair their water deficits after sodium loading, attributable almost entirely to their reduced drinking responses compared with young rats. Lastly, age-related declines in drinking appeared to be more severe in response to hypotension than in response to cellular dehydration.

scholarly journals Differential effects of targeted tongue exercise and treadmill running on aging tongue muscle structure and contractile properties

2013 ◽  
Vol 114 (4) ◽  
pp. 472-481 ◽  
Author(s):  
Heidi Kletzien ◽  
John A. Russell ◽  
Glen E. Leverson ◽  
Nadine P. Connor
Keyword(s):  
Young Adult ◽  
Exercise Group ◽  
Contractile Properties ◽  
Treadmill Running ◽  
Brown Norway ◽  
Middle Aged ◽  
Adult Rats ◽  
Tongue Muscle ◽  
Muscle Structure ◽  
Old Rats

Age-associated changes in tongue muscle structure and strength may contribute to dysphagia in elderly people. Tongue exercise is a current treatment option. We hypothesized that targeted tongue exercise and nontargeted exercise that activates tongue muscles as a consequence of increased respiratory drive, such as treadmill running, are associated with different patterns of tongue muscle contraction and genioglossus (GG) muscle biochemistry. Thirty-one young adult, 34 middle-aged, and 37 old Fischer 344/Brown Norway rats received either targeted tongue exercise, treadmill running, or no exercise (5 days/wk for 8 wk). Protrusive tongue muscle contractile properties and myosin heavy chain (MHC) composition in the GG were examined at the end of 8 wk across groups. Significant age effects were found for maximal twitch and tetanic tension (greatest in young adult rats), MHCIIb (highest proportion in young adult rats), MHCIIx (highest proportion in middle-aged and old rats), and MHCI (highest proportion in old rats). The targeted tongue exercise group had the greatest maximal twitch tension and the highest proportion of MHCI. The treadmill running group had the shortest half-decay time, the lowest proportion of MHCIIa, and the highest proportion of MHCIIb. Fatigue was significantly less in the young adult treadmill running group and the old targeted tongue exercise group than in other groups. Thus, tongue muscle structure and contractile properties were affected by both targeted tongue exercise and treadmill running, but in different ways. Studies geared toward optimizing dose and manner of providing targeted and generalized tongue exercise may lead to alternative tongue exercise delivery strategies.

Effects of Chinese Herbal Prescriptions on Copulatory Activity in Aged Male Rats: A Preliminary Study

1998 ◽  
Vol 26 (01) ◽  
pp. 83-90 ◽  
Author(s):  
Hui-Chiu Chang ◽  
Sheng-l Lue ◽  
Chin Hsu ◽  
Hseng-Kuang Hsu ◽  
Ching-Feng Weng ◽  
...  
Keyword(s):  
Serum Testosterone ◽  
Copulatory Behavior ◽  
Male Rats ◽  
Aged Rats ◽  
Middle Aged ◽  
Promotional Effect ◽  
Before And After ◽  
Copulatory Activity ◽  
Old Rats ◽  
Herbal Prescription

Four herbal prescription medicines, Chi-Pao-Mei-Jan-Tan, Gui-Fu-Ba-Wei-Wan, Huan-Shao-Tan; and San Tsai-Feng-Sui-Tan, were tested for their effects on sexual behavior in aged rats. Crude liquid extracts of these herbs were administered to the rats daily through oral tubing for 14 days. All four herbal prescriptions showed some effects in restoration of mount and intromission behaviors, but there was no effect on restoration of ejaculation in 26 month old rats that had exhibited no copulatory activity (no mount, intromission and ejaculation) previously. The effects of Chi-Pao-Mei-Jan-Tan were further tested in 26 month old rats with low mount and intromission activities but without ejaculation behavior, and in 15 month old rats (middle-age group) that showed normal mount and intrornission behavior but no ejaculation activity. Chi-Pao-Mei-Jan-Tan was effective in improving the frequency of both mount and intromission, but failed to restore the ejaculation activity of the old rats with low mount and intromission behaviors. It was, however, very effective in restoration of ejaculation activity in middle-aged rats that exhibited normal mount and intromission behaviors. Serum testosterone (T) levels of Chi-Pao-Mei-Jan- Tan in tested old and middle-aged rats were determined by radioimmunoassay, and showed no difference before and after treatment. Our findings demonstrated that the four herbal prescriptions had some effects in restoration of mount and intromission behaviors, but not ejaculation activity in old rats, and that Chi-Pao-Mei-Jan-Tan was very effective in restoration of ejaculation activity in middle-aged rats. The promotional effect of Chi-Pao-Mei-Jan-Tan on copulatory behavior was not correlated with serum T levels.

scholarly journals Effects of β-adrenergic receptor agonists on drinking and arterial blood pressure in young and old rats

2011 ◽  
Vol 300 (4) ◽  
pp. R1001-R1008 ◽  
Author(s):  
Robert L. Thunhorst ◽  
Connie L. Grobe ◽  
Terry G. Beltz ◽  
Alan Kim Johnson
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Aged Rats ◽  
Middle Aged ◽  
Young Rats ◽  
Arterial Blood ◽  
Age Related ◽  
Old Rats

These experiments examined water-drinking and arterial blood pressure responses to β-adrenergic receptor activation in young (4 mo), “middle-aged” adult (12 mo), and old (29 mo) male rats of the Brown-Norway strain. We used isoproterenol to simultaneously activate β1- and β2-adrenergic receptors, salbutamol to selectively activate β2-adrenergic receptors, and the combination of isoproterenol and the β2-adrenergic receptor antagonist ICI 118,551 to stimulate only β1-adrenergic receptors. Animals received one of the drug treatments, and water drinking was measured for 90 min. About 1 wk later, animals received the same drug treatment for measurement of arterial blood pressure responses for 90 min. In some rats, levels of renin and aldosterone secretion in response to isoproterenol or salbutamol were measured in additional tests. Old and middle-aged rats drank significantly less after isoproterenol than did young rats and also had greater reductions in arterial blood pressure. Old and middle-aged rats drank significantly less after salbutamol than did young rats, although reductions in arterial blood pressure were equivalent across the ages. The β2-adrenergic antagonist ICI 118,551 abolished drinking after isoproterenol and prevented most of the observed hypotension. Renin secretion after isoproterenol and salbutamol was greater in young rats than in middle-aged rats, and wholly absent in old rats. Aldosterone secretion was reduced in old rats compared with young and middle-aged rats after treatment with isoproterenol, but not after treatment with salbutamol. In conclusion, there are age-related differences in β-adrenergic receptor-mediated drinking that can be explained only in part by age-related differences in renin secretion after β-adrenergic receptor stimulation.

Anatomic capillarization is maintained in relative excess of fiber oxidative capacity in some skeletal muscles of late middle-aged rats

2004 ◽  
Vol 96 (6) ◽  
pp. 2257-2264 ◽  
Author(s):  
Russell T. Hepple ◽  
Janis E. Vogell
Keyword(s):  
Young Adult ◽  
Skeletal Muscles ◽  
Oxidative Capacity ◽  
Brown Norway ◽  
Aged Rats ◽  
Middle Aged ◽  
White Region ◽  
Wide Range ◽  
The Individual ◽  
Gastrocnemius Muscles

The anatomic size of the capillary-to-fiber (C/F) interface plays an important role in O2 flux from blood to tissue by determining the surface area available for diffusion and is maintained in relative proportion to fiber mitochondrial volume across a wide range of muscle aerobic capacity. In the present study, we examined an estimate of the anatomic size of the C/F interface [the quotient of the individual C/F ratio and fiber perimeter, C/F perimeter exchange (CFPE) index] and fiber oxidative capacity in different skeletal muscles, or muscle regions, to test the hypothesis that capillarization would be maintained in relative excess of reduced fiber oxidative capacity in aged muscles. The right gastrocnemius, plantaris, and soleus muscles from young adult (8 mo old) and late middle-aged (28–30 mo old) Fischer 344 × Brown Norway F1 hybrid rats were excised for evaluation of flux through electron transport chain complexes I–III and/or morphometric estimation of capillarization. Muscle mass was lower in the gastrocnemius muscles of the older animals (2,076 ± 32 vs. 1,825 ± 47 mg in young adult vs. late middle-aged, respectively; mean ± SE) but not the plantaris or soleus muscles. Fibers were smaller in the white region of gastrocnemius muscles but larger in the red region of gastrocnemius muscles of the older animals. There was no difference in the number of capillaries around a fiber, the individual C/F ratio, or the CFPE index between groups for any muscle/region, whereas flux through complexes I–III was reduced by 29–43% in late middle-aged animals. Thus the greater quotient of indexes of anatomic capillarity (individual C/F ratio or CFPE index) and fiber oxidative capacity in soleus and the white region of gastrocnemius muscles, but not in the red region of gastrocnemius muscles of the older animals, shows that anatomic capillarity is maintained in relative excess of oxidative capacity in some muscle regions in late middle-aged rats.

Aging alters the contribution of nitric oxide to regional muscle hemodynamic control at rest and during exercise in rats

2011 ◽  
Vol 111 (4) ◽  
pp. 989-998 ◽  
Author(s):  
Daniel M. Hirai ◽  
Steven W. Copp ◽  
K. Sue Hageman ◽  
David C. Poole ◽  
Timothy I. Musch
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Treadmill Running ◽  
Advanced Age ◽  
Whole Body ◽  
Brown Norway ◽  
Young Rats ◽  
Hindlimb Muscle ◽  
Old Rats ◽  
Effects Of Aging

Advanced age is associated with altered skeletal muscle hemodynamic control during the transition from rest to exercise. This study investigated the effects of aging on the functional role of nitric oxide (NO) in regulating total, inter-, and intramuscular hindlimb hemodynamic control at rest and during submaximal whole body exercise. We tested the hypothesis that NO synthase inhibition ( N G-nitro-l-arginine methyl ester, l-NAME; 10 mg/kg) would result in attenuated reductions in vascular conductance (VC) primarily in oxidative muscles in old compared with young rats. Total and regional hindlimb muscle VCs were determined via radiolabeled microspheres at rest and during treadmill running (20 m/min, 5% grade) in nine young (6–8 mo) and seven old (27–29 mo) male Fisher 344 × Brown Norway rats. At rest, l-NAME increased mean arterial pressure (MAP) significantly by ∼17% and 21% in young and old rats, respectively. During exercise, l-NAME increased MAP significantly by ∼13% and 19% in young and old rats, respectively. Compared with young rats, l-NAME administration in old rats evoked attenuated reductions in 1) total hindlimb VC during exercise (i.e., down by ∼23% in old vs. 43% in young rats; P < 0.05), and 2) VC in predominantly oxidative muscles both at rest and during exercise ( P < 0.05). Our results indicate that the dependency of highly oxidative muscles on NO-mediated vasodilation is markedly diminished, and therefore mechanisms other than NO-mediated vasodilation control the bulk of the increase in skeletal muscle VC during the transition from rest to exercise in old rats. Reduced NO contribution to vasomotor control with advanced age is associated with blood flow redistribution from highly oxidative to glycolytic muscles during exercise.

scholarly journals Effect of β-alanine supplementation on carnosine and histidine content in the hippocampus of 14-month-old rats

2019 ◽  
Vol 44 (10) ◽  
pp. 1112-1115 ◽  
Author(s):  
Jay R. Hoffman ◽  
John A. Rathmacher ◽  
Jennifer Robinson ◽  
Yftach Gepner ◽  
Hagit Cohen
Keyword(s):  
Male Rats ◽  
Aged Rats ◽  
Middle Aged ◽  
Old Rats

Carnosine and histidine content in the hippocampus of 14-month-old male rats was examined following 30 days of β-alanine supplementation. All animals were provided identical diets; however, 100 mg of β-alanine was mixed with glucomannan (80:20 blend) in the water of β-alanine supplemented animals. Hippocampal carnosine content was significantly greater (p = 0.005) for β-alanine compared with control, while no differences (p = 0.438) were noted in histidine content between groups. Results provide initial evidence that β-alanine supplementation increases carnosine content in the hippocampus of middle-aged rats, without compromising histidine content. β-Alanine supplementation increases hippocampal carnosine content without compromising histidine content in middle-aged rats.

Age-related changes in the diurnal rhythm of CRH gene expression in the paraventricular nuclei

1996 ◽  
Vol 270 (2) ◽  
pp. E238-E243 ◽  
Author(s):  
A. Cai ◽  
P. M. Wise
Keyword(s):  
Diurnal Rhythm ◽  
Adrenocorticotropic Hormone ◽  
Age Groups ◽  
Aged Rats ◽  
Middle Aged ◽  
Paraventricular Nuclei ◽  
Age Related ◽  
Old Rats ◽  
Two Age Groups

A circadian rhythm secretion of corticotropin-releasing hormone (CRH) is thought to regulate the circadian pattern of secretion of adrenocorticotropic hormone and corticosterone. We have previously reported that the amplitude of the diurnal rhythm of serum corticosterone concentrations decreases in 17- to 20-mo-old rats. In the present experiment, we tested whether an age-related alteration in the daily rhythm and/or level of CRH mRNA in the paraventricular nuclei (PVN) occurs during middle age. Groups of young and middle-aged animals were killed at several times of day. We assessed the level of CRH mRNA in the PVN and dorsal medial subdivision of the PVN using in situ hybridization. In young rats, CRH mRNA expression exhibited a diurnal rhythm in the dorsal medial PVN. The same trend was observed in the entire medial PVN. In middle-aged rats, no rhythm was detected in either region. The overall average level of CRH mRNA was not different between these two age groups. These findings suggest that changes in the suprachiasmatic nucleus or in its ability to entrain neuroendocrine outputs occur relatively early during the aging process.

scholarly journals STRENGTH TRAINING AND ANABOLIC STEROID DO NOT AFFECT MUSCLE CAPILLARIZATION OF MIDDLE-AGED RATS

2017 ◽  
Vol 23 (2) ◽  
pp. 137-141 ◽  
Author(s):  
Walter Krause Neto ◽  
Eliane Florencio Gama
Keyword(s):  
Anabolic Steroid ◽  
Skeletal Muscles ◽  
Wistar Rats ◽  
Extensor Digitorum Longus ◽  
Aged Rats ◽  
Middle Aged ◽  
Cross Sectional ◽  
Anabolic Agent ◽  
Volumetric Density ◽  
Old Rats

ABSTRACT Introduction: It is generally accepted that the capillary network decreases with advancing age. The combined effect of resistance training (RT) and testosterone still needs to be elucidated. Objective: This study aimed to measure capillary profile of different skeletal muscles of middle-aged rats undergoing RT and administration of exogenous testosterone. Methods: Wistar rats were divided into five experimental groups: control with 13-month-old rats (SC), control with 16-month-old rats (SE), aged rats + anabolic agent (SA), aged rats + RT (T), and aged rats + RT + anabolic agent (TA). Results: For soleus, the SE group presented a decrease in the percentage of capillaries in comparison to SC group. SA, T, and TA groups had increased capillary volume in comparison to SC. As for the extensor digitorum longus (EDL), SA, T, and TA groups demonstrated lower capillary volume and numeric density in comparison to SC and SE. The EDL of the T and TA groups presented 70% less capillaries than soleus. The numerical and volumetric density and capillary ratio by muscle fiber were not statistically altered by any intervention. The cross-sectional area (CSA) of the soleus of the SA, T and TA groups was statistically different from SC group. The soleus CSA was greater in the TA and T groups than in the SC, SE and SA groups, and the EDL CSA was greater in the TA compared to all other groups. The TA group had greater values than the SE, SA, and T groups. Conclusion: The type of intervention used did not affect any variables measured in the capillary profile. However, the use of anabolic steroid and/or RT showed a tendency to decrease the density of capillaries in the EDL.

Thirst and salt appetite responses in young and old Brown Norway rats

2003 ◽  
Vol 284 (2) ◽  
pp. R317-R327 ◽  
Author(s):  
Robert L. Thunhorst ◽  
Alan Kim Johnson
Keyword(s):  
Drinking Water ◽  
Body Weight ◽  
Extracellular Fluid ◽  
Brown Norway ◽  
Fluid Restriction ◽  
Salt Appetite ◽  
Young Rats ◽  
Daily Ingestion ◽  
Old Rats ◽  
Norway Rats

Male Brown Norway rats aged 4 mo (young) and 20 mo (old) received a series of experimental challenges to body fluid homeostasis over ∼3 mo. Water was available for drinking in some tests, and both water and 0.3 M NaCl were available in others. The series included three episodes of extracellular fluid depletion (i.e., furosemide + 20 h of sodium restriction), two tests involving intracellular fluid depletion (i.e., hypertonic saline: 1 or 2 M NaCl at 2 ml/kg body wt sc), one test involving overnight food and fluid restriction, and testing with captopril adulteration of the drinking water (0.1 mg/ml) for several days. Old rats were significantly heavier than young rats throughout testing. Old rats drank less water and 0.3 M NaCl after sodium deprivation than young rats, in terms of absolute and body weight-adjusted intakes. Old rats drank only half as much water as young rats in response to subcutaneous hypertonic NaCl when intakes were adjusted for body weight. Old rats drank less 0.3 M NaCl than young rats after overnight food and fluid restriction when intakes were adjusted for body weight. In response to captopril adulteration of the drinking water, young rats significantly increased daily ingestion of 0.3 M NaCl when it was available as an alternative to water and significantly increased daily water intakes when only water was available, in terms of absolute and body weight-adjusted intakes. Old rats had no response to captopril treatment. These results add important new information to previous reports that aging rats have diminished thirst and near-absent salt appetite responses to regulatory challenges.

Sign in / Sign up

Export Citation Format

Share Document