Adrenalectomy eliminates both fiber-type differences and starvation effects on denervated muscle

1988 ◽  
Vol 255 (6) ◽  
pp. E850-E856 ◽  
Author(s):  
R. R. Almon ◽  
D. C. Dubois
Keyword(s):  
Muscle Mass ◽  
Extensor Digitorum Longus ◽  
Fiber Type ◽  
Sprague Dawley ◽  
Denervated Muscle ◽  
Adrenalectomized Animal ◽  
Sprague Dawley Rats ◽  
Starvation Effects ◽  
The Difference ◽  
Denervated Muscles

This report describes changes in muscle mass of innervated and denervated pairs of muscles taken from intact and adrenalectomized 250-g male Sprague-Dawley rats provided with different diets. Diets ranged from a nutritionally complete liquid diet to starvation (water only). In the intact animals, muscles with a more tonic character (soleus) are less sensitive to starvation than are muscles with a more phasic character (extensor digitorum longus), whereas the opposite is true of denervation. In the intact animals, starvation greatly increased the amount of atrophy following denervation. In the adrenalectomized animals, starvation had no effect on the amounts of atrophy following denervation. Furthermore, adrenalectomy virtually eliminated the fiber-type differences in the amount of atrophy following denervation. In addition, a comparison between denervated muscles from intact animals and adrenalectomized animals subjected to starvation demonstrates that all denervated muscles from the adrenalectomized animals atrophy less. Finally, it was observed that although an adrenalectomized animal can tolerate 6 days of starvation, an adrenalectomized-castrated animal cannot tolerate even short periods of starvation. The difference appears to be due to low amounts of corticosterone of testicular origin.

Denervation enhances the physiological effects of the KATP channel during fatigue in EDL and soleus muscle

2001 ◽  
Vol 281 (1) ◽  
pp. R56-R65 ◽  
Author(s):  
W. Matar ◽  
J. A. Lunde ◽  
B. J. Jasmin ◽  
J.-M. Renaud
Keyword(s):  
Soleus Muscle ◽  
Katp Channel ◽  
Extensor Digitorum Longus ◽  
Channel Blocker ◽  
Major Effect ◽  
Physiological Effects ◽  
Denervated Muscle ◽  
Resting Tension ◽  
The Difference ◽  
Denervated Muscles

The objective was to determine whether denervation reduces or enhances the physiological effects of the KATP channel during fatigue in mouse extensor digitorum longus (EDL) and soleus muscle. For this, we measured the effects of 100 μM of pinacidil, a channel opener, and of 10 μM of glibenclamide, a channel blocker, in denervated muscles and compared the data to those observed in innervated muscles from the study of Matar et al. (Matar W, Nosek TM, Wong D, and Renaud JM. Pinacidil suppresses contractility and preserves energy but glibenclamide has no effect during fatigue in skeletal muscle. Am J Physiol Cell Physiol 278: C404–C416, 2000). Pinacidil increased the 86Rb+ fractional loss during fatigue, and this effect was 2.6- to 3.4-fold greater in denervated than innervated muscle. Pinacidil also increased the rate of fatigue; for EDL the effect was 2.5-fold greater in denervated than innervated muscle, whereas for soleus the difference was 8.6-fold. A major effect of glibenclamide was an increase in resting tension during fatigue, which was for the EDL and soleus muscle 2.7- and 1.9-fold greater, respectively, in denervated than innervated muscle. A second major effect of glibenclamide was a reduced capacity to recover force after fatigue, an effect observed only in denervated muscle. We therefore suggest that the physiological effects of the KATP channel are enhanced after denervation.

Immunohistochemical Detection of Motor Endplates in the Long-Term Denervated Muscle

2018 ◽  
Vol 34 (05) ◽  
pp. 348-358 ◽  
Author(s):  
Jingming Chen ◽  
Jing Li ◽  
Themba Nyirenda ◽  
Mary Fowkes ◽  
Stanislaw Sobotka ◽  
...  
Keyword(s):  
Sprague Dawley ◽  
Denervated Muscle ◽  
Muscle Weight ◽  
Motor Endplates ◽  
Sprague Dawley Rats ◽  
Intramuscular Nerve ◽  
Nerve Muscle ◽  
Denervated Muscles ◽  
Induced Changes

Background We have demonstrated that the native motor zone (NMZ) within a muscle is an ideal target for performing nerve-muscle-endplate band grafting (NMEG) to restore motor function of a denervated muscle. This study was designed to determine spatiotemporal alterations of the myofibers, motor endplates (MEPs), and axons in the NMZ of long-term denervated muscles for exploring if NMEG-NMZ technique would have the potential for delayed reinnervation. Methods Sternomastoid (SM) muscles of adult female Sprague-Dawley rats (n = 21) were experimentally denervated and denervation-induced changes in muscle weight, myofiber size, MEPs, and intramuscular nerve axons were evaluated histomorphometrically and immunohistochemically at the end of 3, 6, and 9 months after denervation. The values obtained from the ipsilateral normal side served as control. Results The denervated SM muscles exhibited a progressive reduction in muscle weight (38%, 31%, and 19% of the control) and fiber diameter (52%, 40%, and 28% of the control) for 3-, 6-, and 9-month denervation, respectively. The denervated MEPs were still detectable even 9 months after denervation. The mean number of the denervated MEPs was 79%, 65%, and 43% of the control in the 3-, 6-, and 9-month denervated SM, respectively. Degenerated axons in the denervated muscles became fragmented. Conclusions Persistence of MEPs in the long-term denervated SM suggests that some surgeries targeting the MEPs such as NMEG-NMZ technique should be effective for delayed reinnervation. However, more work is needed to develop strategies for preservation of muscle mass and MEPs after denervation.

Loss of hypoxic pulmonary vasoconstriction in chronic pneumonia is not mediated by nitric oxide

1993 ◽  
Vol 265 (5) ◽  
pp. H1523-H1528 ◽  
Author(s):  
D. G. McCormack ◽  
N. A. Paterson
Keyword(s):  
Nitric Oxide ◽  
Pressor Response ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Sprague Dawley ◽  
Absolute Increase ◽  
Pulmonary Vasoconstriction ◽  
Sprague Dawley Rats ◽  
Before And After ◽  
Inflammatory Processes ◽  
The Difference

In pulmonary inflammatory processes such as pneumonia there is diminished hypoxic pulmonary vasoconstriction (HPV). We investigated whether the attenuated HPV in pneumonia is a due to excess nitric oxide (NO) release. Sprague-Dawley rats were anesthetized, and a slurry (0.06 ml) of infected agar beads (containing 6 x 10(5) Pseudomonas aeruginosa organisms) or control (sterile) beads was then injected into a distal bronchus through a tracheotomy. After the establishment of a chronic P. aeruginosa pneumonia (7-10 days later) animals were instrumented for hemodynamic monitoring, and the response to exposure to hypoxic gas (fraction of inspired O2 = 0.08) was recorded before and after the administration of NG-monomethyl-L-arginine (L-NMMA; 50 mg/kg), an inhibitor of NO synthesis. The hypoxic pressor response, as assessed by the absolute increase in pulmonary arterial pressure (PAP) and total pulmonary resistance (TPR), was reduced in infected animals compared with control animals. The change in PAP and TPR was 8.5 +/- 0.7 and 0.053 +/- 0.007, respectively, in control animals compared with 5.9 +/- 0.5 and 0.041 +/- 0.011 in infected animals. After L-NMMA the increase in PAP and TPR during hypoxia was greater in both control and infected animals. However, treatment with L-NMMA did not affect the difference between control and infected animals. We conclude that excess release of NO does not account for the attenuated hypoxic pressor response in pneumonia.

Blood flow in normal and denervated muscle during exercise in conscious rats

1988 ◽  
Vol 255 (6) ◽  
pp. H1509-H1515 ◽  
Author(s):  
M. D. Delp ◽  
R. B. Armstrong
Keyword(s):  
Blood Flow ◽  
Muscular Activity ◽  
Sprague Dawley ◽  
Blood Flows ◽  
Sprague Dawley Rats ◽  
Mechanical Factors ◽  
Denervated Muscles ◽  
Gastrocnemius Muscles ◽  
Low Intensity Exercise ◽  
Hyperemic Response

The purpose of this study was to test the hypothesis that extrinsic mechanical factors, i.e., the dynamic shortening and lengthening imposed on a muscle during limb movements and the rhythmic compressions as surrounding muscles contract and relax, contribute to the initial muscle hyperemia during locomotion in conscious male Sprague-Dawley rats. Soleus and lateral head of gastrocnemius muscles were surgically denervated in one hindlimb several hours before exercise to remove 1) local metabolic vasodilator effects, 2) vasoconstrictor or vasodilatory influences mediated through sympathetic postganglionic fibers, and 3) intrinsic mechanical pumping. Blood flow was measured with radioactive microspheres during preexercise and at 30 s and 5 min of exercise in rats walking at 15 m/min or a motor-driven treadmill. Glycogen concentrations were also measured as an indicator of muscular activity to verify the denervation. Blood flows to control muscles in the normal limb were similar to previously reported values during preexercise and exercise. Denervation, however, decreased preexercise blood flow (69–88%) to muscle composed predominantly of oxidative fibers and increased flow (53%) to muscle composed predominantly of glycolytic fibers. During exercise, blood flow to denervated muscles either remained unchanged or decreased. These data suggest that extrinsic mechanical factors do not significantly contribute to the initial hyperemic response at the onset of low-intensity exercise in normal muscle.

HEXAFLUORODIETHYL ETHER (INDOKLON) CONVULSIONS IN CORPUS-CALLOTOMIZED WHITE RATS

1964 ◽  
Vol 42 (5) ◽  
pp. 609-621 ◽  
Author(s):  
H. R. Butler ◽  
S. J. Manax ◽  
G. W. Stavraky
Keyword(s):  
Sprague Dawley ◽  
White Rats ◽  
Sprague Dawley Rats ◽  
Maximal Sensitivity ◽  
The Difference

The convulsant threshold of 24 corpus-callotomized Sprague–Dawley rats exposed to Indoklon vapor once a week was found to be significantly lower than that of 24 sham-operated controls in the second, third, and fourth exposures; the sensitivity of both groups of animals increased progressively and levelled out at the fifth exposure. Repetition of the experiment after 3 weeks of rest, with exposures spaced at 48-hour intervals, further lowered the convulsant threshold of the animals, both groups exhibiting a similar, and possibly maximal, sensitivity to Indoklon at the second exposure. When in another series, 60 corpus-callotomized rats and 60 sham-operated controls were injected intraperitoneally with CD10 of Indoklon at weekly intervals, the susceptibility of both groups to convulsions again increased rapidly during the first four injections; at the second injection, the corpus-callotomized rats were significantly more sensitive to Indoklon than the controls. During the fifth to eighth injection, the convulsibility of the animals reached a plateau, 62.2% to 78.5% of the rats convulsing; the difference between the two groups at this stage became less marked, though the convulsions in corpus-callotomized animals continued to be of longer duration than in the controls. Repetition of the injections, spaced at 48-hour intervals, after 3 months of rest, demonstrated a continuing high and equal sensitivity of the two groups of rats to Indoklon with some depression setting in during the second half of a series of 12 injections.

Strain Differences Occurring in an Experimental Study of Punishment

1965 ◽  
Vol 16 (2) ◽  
pp. 531-536 ◽  
Author(s):  
Morton H. Kleban
Keyword(s):  
Experimental Study ◽  
Empirical Evidence ◽  
Wistar Rats ◽  
Strain Differences ◽  
Training Procedure ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Y Maze ◽  
Minimum Number ◽  
The Difference

Forty-three Sprague-Dawley and 43 Wistar rats were given reward training for 40 trials in a Y-maze. On the next 20 trials, control groups were continued under the same training procedure, and 50% shock trials were introduced in the training of the remaining rats. For the extinction training, the reward was shifted to the opposite arm and 50% shock was continued for the no-delay and 30-sec. delay shock groups. The most significant results were that in the 30-sec. delay groups, the delay helped the Sprague-Dawley rats reverse in a minimum number of trials, whereas the Wistar rats showed strong indications of response stereotypy. The findings with respect to the Sprague-Dawley rats supported the empirical evidence on the effectiveness of delay in overcoming response persistence and the findings on the Wistar rats supported the empirical evidence on omission in punishment. The difference in response to punishment between the two albino strains emphasizes the need for experimental study of strain factors. Experiments should be repeated with several animal strains to remedy over-generalization from single strains and to help elaborate our understanding of the interaction present between punishment and strains.

Daily rhythm of NaCl intake in rats fed low-Ca2+ diet: relation to plasma and urinary minerals and hormones

1996 ◽  
Vol 270 (3) ◽  
pp. R505-R517 ◽  
Author(s):  
M. G. Tordoff ◽  
A. Okiyama
Keyword(s):  
Dark Period ◽  
Plasma Concentrations ◽  
Salt Appetite ◽  
Sprague Dawley ◽  
Lower Plasma ◽  
Plasma Osmolarity ◽  
Dihydroxyvitamin D3 ◽  
Sprague Dawley Rats ◽  
The Difference ◽  
Plasma Phosphorus

To assess daily rhythms of salt appetite, we measured spontaneous 300 mM NaCl intake of male Sprague-Dawley rats fed a diet containing 150 or 25 mmol Ca2+/kg. Both groups drank most NaCl at night, but, as the dark period progressed, intakes of controls remained constant or diminished, whereas intakes of rats fed low-Ca2+ diet increased. During the late dark period, when the difference in NaCl intake between the two dietary groups was greatest, rats fed a low-Ca2+ diet lost more corticosterone and sodium in urine, had lower plasma osmolarity, and had higher plasma adrenocorticotropic hormone (ACTH) and corticosterone concentrations than did controls. Over the 24-h cycle, rats fed the low-Ca2+ diet excreted less Ca2+ and more corticosterone in urine than did controls. They also had consistently lower plasma concentrations of Ca2+ and renin activity and consistently higher plasma phosphorus, arginine vasopressin, parathyroid hormone, thyroxine, calcitonin, and 1,25-dihydroxyvitamin D3. These findings support the hypothesis that salt appetite induced by dietary Ca2+ deficiency involves a subtle dysfunction of the ACTH-corticosterone axis, but they also raise several other possibilities.

Mass spectrometry for monitoring respiratory and anesthetic gas waveforms in rats

1988 ◽  
Vol 65 (2) ◽  
pp. 955-963 ◽  
Author(s):  
D. R. Larach ◽  
H. G. Schuler ◽  
T. M. Skeehan ◽  
J. A. Derr
Keyword(s):  
Mass Spectrometric ◽  
Laboratory Animals ◽  
Sprague Dawley ◽  
Arterial Pco2 ◽  
Sprague Dawley Rats ◽  
Reflex Movement ◽  
The Difference ◽  
End Tidal ◽  
Respiratory Gases ◽  
End Tidal Co2

A method is presented for real-time monitoring of airway gas concentration waveforms in rats and other small animals. Gas is drawn from the tracheal tube, analyzed by a mass spectrometer, and presented as concentration vs. time waveforms simultaneously for CO2, halothane, and other respiratory gases and anesthetics. By use of a respiratory simulation device, the accuracy of mass spectrometric end-tidal CO2 analysis was compared with both the actual gas composition and infrared spectrophotometry. The effects of various ventilator rates and inspiration-to-expiration ratios on sampling accuracy were also examined. The technique was validated in male Sprague-Dawley rats being ventilated mechanically. The difference between the arterial PCO2 (PaCO2) and the end-tidal PCO2 (PETCO2) was not significantly different from zero, and the correlation between PETCO2 and PaCO2 was strong (r = 0.97, P less than 0.0001). Continuous gas sampling for periods up to 5 min did not affect PaCO2, PETCO2, or airway pressures. By use of this new method for measuring end-tidal halothane concentrations in rats approximately 6.5 mo of age, the minimum alveolar concentration of halothane that prevented reflex movement in response to tail clamping was 0.97 +/- 0.04% atmospheric (n = 14). This mass spectrometric technique can be used in small laboratory animals, such as rats, weighing as little as 250 g. Gas monitoring did not distort either PETCO2 or PaCO2. Under the defined conditions of this study, accurate and simultaneous measurements of phasic respiratory concentrations of anesthetic and respiratory gases can be achieved.

scholarly journals A 90-Day Oral (Dietary) Toxicity Study of Rebaudioside A in Sprague-Dawley Rats

2008 ◽  
Vol 27 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Andrey I Nikiforov ◽  
Alex K Eapen
Keyword(s):  
Clinical Pathology ◽  
Stevia Rebaudiana ◽  
Rebaudioside A ◽  
Sprague Dawley ◽  
Small Magnitude ◽  
Stevia Rebaudiana Bertoni ◽  
Sprague Dawley Rats ◽  
The Difference ◽  
High Concentrations ◽  
And Behavior

Rebaudioside A is one of several glycosides found in the leaves of Stevia rebaudiana (Bertoni) Bertoni (Compositae) stevia that has been identified as a potential sweetener. The present study (initiated in April 2006 and completed in October 2006) evaluated the safety of this sweetener when administered as a dietary admix at target exposure levels of 500, 1000, and 2000 mg/kg/day to Sprague-Dawley rats for 90 days. There were no treatment-related effects on the general condition and behavior of the animals as determined by clinical observations, functional observational battery, and locomotor activity assessments. Evaluation of clinical pathology parameters revealed no toxicologically relevant, treatment-related effects on hematology, serum chemistry, or urinalysis. Macroscopic and microscopic findings revealed no treatment-related effects on any organ evaluated. Lower mean body weight gains were noted in males in the 2000 mg/kg/day group throughout the study, which was considered to be test article related; however, given the small magnitude of the difference as compared to controls, this effect was not considered to be adverse. Results of this study clearly demonstrate that dietary administration of high concentrations of rebaudioside A for 90 consecutive days to Sprague-Dawley rats was not associated with any signs of toxicity.

Preapplication of mitomycin C for enhanced patency of myringotomy

2000 ◽  
Vol 122 (3) ◽  
pp. 346-348
Author(s):  
Scott A. Estrem ◽  
Terry J. Baker
Keyword(s):  
Mitomycin C ◽  
Patency Rate ◽  
Saline Solution ◽  
Ktp Laser ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Tube Dysfunction ◽  
Ventilation Tubes ◽  
Alternative Techniques ◽  
The Difference

OBJECTIVES Ventilation tubes are the mainstay of surgical treatment for eustachian tube dysfunction and have been used successfully for many years. Certain disadvantages of ventilation tubes, however, have prompted research into alternative techniques including laser myringotomy. We investigated the use of KTP laser myringotomy in conjunction with topical mitomycin C to delay healing and prolong the patency of the myringotomy. METHODS Twenty myringotomies were created in 10 Sprague-Dawley rats. A solution of mitomycin C was applied to the intact tympanic membrane for 15 minutes. The solution was then suctioned free, and a myringotomy was created with a KTP laser. Fifty-three rats with saline application serving as controls from a previous study were used to allow statistical assessment. RESULTS The myringotomies remained open for a median of 9.5 weeks. Control myringotomies, which received saline solution instead of mitomycin C, healed within a median of 1.5 weeks. The difference was statistically significant at P < 0.0001. No complications were noted. CONCLUSION Topically administered mitomycin C before laser myringotomy is effective in prolonging the patency of laser myringotomies in rats. The patency rate is similar to that achieved in experiments in which topical mitomycin C is placed into the myringotomy site created by the laser.

Sign in / Sign up

Export Citation Format

Share Document