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1.
Life (Basel) ; 14(2)2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38398720

ABSTRACT

Total hip and knee replacements are the most common orthopedic procedures performed due to osteoarthritis. Pain is an intrinsic symptom accompanying osteoarthritis, persisting long before surgery, and continuing during the preoperative and postoperative periods. Appropriate pain management after surgery determines the comfort, duration, and cost of hospitalization, as well as the effectiveness of postoperative rehabilitation. Individual differences in pain perception and tolerance in orthopedic patients remain an important research topic. Therefore, the aim of this study was to investigate the predictors of analgesic requirements (morphine, acetaminophen, and ketoprofen), including individual pain threshold and tolerance, body mass index (BMI), diabetes, and beliefs about pain control in patients undergoing elective hip or knee arthroplasty using a multilevel regression model (N = 147, 85 women, 62 men, 107 after hip replacement, and 40 after knee replacement). Results: Higher pain tolerance was associated with a lower dose of morphine per kg after surgery. Patients undergoing hip surgery received a lower dose of ketoprofen than patients undergoing knee surgery. The more the patient believed in personal pain control, the stronger the negative relationship between pain tolerance and morphine requirement. The lowest doses were given to patients with the highest pain tolerance and the greatest belief in personal control. Factors such as belief in pain control and pain tolerance should be considered in comprehensive postoperative pain management in orthopedic patients to reduce opioid doses and, thus, side effects.

2.
Langenbecks Arch Surg ; 409(1): 70, 2024 Feb 22.
Article in English | MEDLINE | ID: mdl-38386114

ABSTRACT

INTRODUCTION: The management of CBDS (common bile duct stones) in patients with co-existing gallbladder stones has been debated. Guidelines recommend patients with CBDS identified on imaging should be offered duct clearance; however, this is based on low-quality evidence. This study aimed to investigate the natural history of small CBDS identified using IOUS (intraoperative ultrasound) in patients undergoing cholecystectomy. This may provide evidence to support a short-term expectant management approach in such patients. METHODS: Patients with CBDS diagnosed on IOUS during cholecystectomy were identified from a database of consecutive patients undergoing surgery. Patients with CBDS identified were divided into small stone (SS, ≤5 mm) and large stone (LS, >5 mm) groups. Intraoperative CBDS management, postoperative investigations, postoperative bile duct clearance, re-admissions, complications, length of stay (LOS) and follow-up are described. RESULTS: Fifty-nine of 427 patients had CBDS identified on IOUS. In the SS group (n=51), 46 patients underwent short-term expectant management rather than immediate/planned bile duct clearance. Following short-term expectant management, 41/46 patients (89.1%) did not require postoperative endoscopic retrograde cholangiopancreatography and at >3 year follow-up, none has since presented with residual CBDS. Median LOS was 0 days in the short-term expectant management group and 2 days in the immediate/planned bile duct clearance group, P=0.039. CONCLUSIONS: This study reports the natural history of small CBDS identified on IOUS in patients undergoing cholecystectomy. Such patients were safely treated with short-term expectant management associated with a reduced hospital LOS. This provides rationale for undertaking further research to establish this as a preferred management strategy.


Subject(s)
Gallstones , Humans , Gallstones/diagnostic imaging , Gallstones/surgery , Cholecystectomy , Bile Ducts , Cholangiopancreatography, Endoscopic Retrograde , Databases, Factual
3.
Front Physiol ; 14: 1304534, 2023.
Article in English | MEDLINE | ID: mdl-38148904

ABSTRACT

Background: Pain, a subjective sensation, poses a great challenge to the human body as a stressor. There is empirical evidence that moderate to intense physical activity increases pain tolerance and this may be critical during pregnancy for optimal pregnancy, fetal development, and delivery. To the best of our knowledge, it is the first study examining the changes in pain perception in pregnant women after a maximal progressive exercise test and after 8 weeks of high-intensity interval training (HIIT). Methods: Thirty-five women with uncomplicated singleton pregnancies between 13 and 28 weeks of gestation participated in the study. The HIIT intervention was developed in accordance with the recommendations and available data on HIIT during pregnancy. The maximal progressive cardiopulmonary exercise test was performed on a cycle ergometer with an electronically controlled load. Pressure pain threshold and pressure pain tolerance were measured with an algometer. Results: We found significant effects of the maximal exercise test and high-intensity interval training, such that the pregnant women had higher pain tolerance after the maximal exercise test than before and after the high-intensity interval training than the baseline. Conclusion: Our results suggest that post-exercise analgesia may be important in pregnant women and that high-intensity interval training appears to be beneficial for pregnant women to improve their pain tolerance while being obstetrically safe. Increased pain tolerance before labor could lead to better management of pain during labor and in the postpartum and lactation periods. Increasing pregnant women's awareness of this issue can improve their wellbeing and provide more comfort during labor.

4.
BJS Open ; 7(5)2023 09 05.
Article in English | MEDLINE | ID: mdl-37862616

ABSTRACT

BACKGROUND: Groin hernia repair is one of the most common operations performed globally, with more than 20 million procedures per year. The last guidelines on groin hernia management were published in 2018 by the HerniaSurge Group. The aim of this project was to assess new evidence and update the guidelines. The guideline is intended for general and abdominal wall surgeons treating adult patients with groin hernias. METHOD: A working group of 30 international groin hernia experts and all involved stakeholders was formed and examined all new literature on groin hernia management, available until April 2022. Articles were screened for eligibility and assessed according to GRADE methodologies. New evidence was included, and chapters were rewritten. Statements and recommendations were updated or newly formulated as necessary. RESULTS: Ten chapters of the original HerniaSurge inguinal hernia guidelines were updated. In total, 39 new statements and 32 recommendations were formulated (16 strong recommendations). A modified Delphi method was used to reach consensus on all statements and recommendations among the groin hernia experts and at the European Hernia Society meeting in Manchester on October 21, 2022. CONCLUSION: The HerniaSurge Collaboration has updated the international guidelines for groin hernia management. The updated guidelines provide an overview of the best available evidence on groin hernia management and include evidence-based statements and recommendations for daily practice. Future guideline development will change according to emerging guideline methodology.


Subject(s)
Abdominal Wall , Hernia, Inguinal , Adult , Humans , Hernia, Inguinal/surgery , Groin/surgery , Surgical Mesh
6.
Genes (Basel) ; 14(3)2023 03 16.
Article in English | MEDLINE | ID: mdl-36981004

ABSTRACT

One of the genes associated with pain perception is SCN9A, which encodes an α-subunit of the voltage gated sodium channel, NaV1.7, a crucial player in peripheral pain sensation. It has been suggested that a common missense polymorphism within SCN9A (rs6746030; G>A; R1150W) may affect nociception in the general population, but its effects of pain perception in athletes remain unknown. Therefore, the aim of the study was to investigate the association between a polymorphism within SCN9A (rs6746030) and pain perception (pain threshold and pain tolerance) in the group of combat athletes (n = 214) and students (n = 92) who did not participate in sports at a professional level. Genotyping was carried out using TaqMan Real-Time PCR method. No significant differences were found between the SCN9A genotype distributions with respect to the pain threshold. However, the probability of having a high pain threshold was higher in the combat sports group than in the control group. The probability of having a decreased pain tolerance was higher in the carriers of the GA and AA genotype than in the homozygotes of the GG genotype. Moreover, the possibility of having a high pain threshold was higher in the combat athlete group than in the control group. The results of our study suggest that the SCN9A rs6746030 polymorphism may affect pain perception. However, the additional effect of the experimental group may suggest that pain tolerance is significantly modulated by other factors, such as the systematic exposure of the athletes' bodies to short-term high-intensity stimuli during training sessions.


Subject(s)
Pain , Polymorphism, Single Nucleotide , Humans , Pain Perception , Pain Threshold , Genotype , NAV1.7 Voltage-Gated Sodium Channel/genetics
8.
Article in English | MEDLINE | ID: mdl-36361034

ABSTRACT

The aim of the study was to describe the characteristics and factors related to pain perception in pregnant women, such as optimism, personality traits, and fear of developing COVID-19 consequences. Sixty-six pregnant women aged 23 to 42 years participated in the study, and the comparison group consisted of n = 59 non-pregnant female students aged 19 to 23 years. Pressure pain threshold and pain tolerance were measured with an algometer. To assess psychological characteristics, the Life-Orientation Test-Revised was used to assess optimism, the Fear of COVID-19 Scale was used to assess COVID-19 anxiety, and the Ten-Item Personality Inventory was applied to assess personality traits in a five-factor model. The main results of the study showed that pain tolerance was significantly lower in both dominant and non-dominant hand pregnant women than in the comparison group. The studied pregnant women had higher scores for conscientiousness, fear of COVID-19, and optimism compared with the non-pregnant women. Regression analysis showed that the variability in pain perception among pregnant women could not be explained by individual differences in personality traits, optimism, and fear of COVID-19.


Subject(s)
COVID-19 , Parturition , Pregnancy , Female , Humans , Cross-Sectional Studies , Parturition/psychology , Pain Threshold , COVID-19/epidemiology , Pregnant Women/psychology , Anxiety/epidemiology , Anxiety/psychology , Surveys and Questionnaires
9.
Genes (Basel) ; 13(10)2022 Oct 01.
Article in English | MEDLINE | ID: mdl-36292660

ABSTRACT

Each year approximately 1 million total hip replacements are performed worldwide. The most common indications to choose this procedure are rest pain and pain after activity as well as functional limitations influencing daily activities. Experimental pain is highly variable by individuals, which is partly due to genetics. The aim of the study was to investigate a possible association of the catechol-O-methyltransferase (COMT) and µ-opioid receptor (OPRM1) genotypes with pain perception in patients undergoing total hip replacement and total knee replacement taking into account aspects such as age, sex and diabetes. The study included 207 patients (119 females, 88 males, median age 65 years, range 33−77) that qualified for surgical treatment (total hip replacement and knee arthroplasty) due to osteoarthritis. Pain sensitivity measurement was performed using a standard algometer. The genomic DNA was extracted from the buccal cells.. Single locus analysis was conducted using a general linear model. In the study group, we did not find statistically significant genetic associations between variants of COMT and OPRM1 and pain thresholds/pain tolerance. The analysis of subjective pain perception using the visual analog scale did not show any relationship between the OPRM1 rs1799971A>G variant and COMT rs4680, rs4633, rs4818 and rs6269.


Subject(s)
Arthroplasty, Replacement, Knee , Osteoarthritis , Male , Female , Humans , Adult , Middle Aged , Aged , Catechol O-Methyltransferase/genetics , Mouth Mucosa , Polymorphism, Single Nucleotide , Pain Perception , Pain/genetics , Receptors, Opioid, mu/genetics
10.
Article in English | MEDLINE | ID: mdl-36141549

ABSTRACT

The purpose of this study was to investigate whether regular physical activity can alter the pressure pain threshold, pain tolerance, and subjective pain perception in individuals who have experienced a cardiovascular event. The study involved 85 individuals aged 37 to 84 years (M = 65.36) who qualified for outpatient cardiac rehabilitation, which consisted of 24 physical training sessions. The patients were all tested twice: on the first and last day of the outpatient cardiac rehabilitation program. Assessments of the pressure pain threshold and pain tolerance were performed with an algometer. To assess the pain coping strategies, the Pain Coping Strategies Questionnaire (CSQ) and parenting styles were measured retrospectively with subjective survey questions. The main results of the study showed that patients achieved significantly higher pressure pain thresholds after a physical training cycle (ps < 0.05, η2 = 0.05-0.14), but found no differences in the pain tolerance (ps > 0.05). A lower preference for the better pain coping strategy explanation (ß = -0.42, p = 0.013) and growing up in a family with a less neglectful atmosphere (ß = -0.35, p = 0.008) were associated with increased pressure pain threshold after physical training. The results suggest that physical activity is an important factor in modulating the pressure pain threshold.


Subject(s)
Pain Threshold , Pain , Exercise , Humans , Pain Perception , Retrospective Studies
11.
Nutrients ; 14(3)2022 Jan 25.
Article in English | MEDLINE | ID: mdl-35276873

ABSTRACT

Studies suggest that carnosine (beta-alanyl-L-histidine) is effective in treating neuromuscular diseases associated with aging, but there is still a need to clarify its role in motor units (MUs) function during aging. In this study, 40 male Wistar rats aged 15 months were randomly assigned to a control or to two experimental groups in which 0.1% carnosine supplementation was performed for 10 or 34 weeks. After 34 weeks, we examined fast fatigable (FF), fast fatigue-resistant (FR) and slow (S) MUs' force properties and fatigability, as well as antioxidant potential, advanced glycation end products, activity of enzymes, and histidyl dipeptides content in the medial gastrocnemius muscle. Short- and long-term carnosine supplementation maintained the force of FF MUs at a higher level during its rapid decline seen from the initial 10 to 70 s of the fatigue test. In FF, especially long-term, and in FR MUs, especially short-term, carnosine supplementation resulted in less rapid force decline during the initial 70 s of the second fatigue protocol. Carnosine supplementation did not change muscle antioxidant potential and mortality rate (~35% in all groups), nor muscle mass with aging. Moreover, instead of the expected increase, a decrease in histidyl dipeptides by ~30% in the red portion of medial gastrocnemius muscle after long-term supplementation was found. After chronic carnosine supplementation, the specific changes in fatigue resistance were observed in FF and FR units, but not in S MU types that were not accompanied by an improvement of antioxidant potential and activity of glycolytic or oxidative enzymes in aged rats. These observations indicate that carnosine supplementation during aging may generate different physiological adaptations which should be considered as an important factor when planning treatment strategies.


Subject(s)
Carnosine , Muscle Contraction , Animals , Carnosine/pharmacology , Dietary Supplements , Male , Motor Neurons , Muscle Contraction/physiology , Muscle, Skeletal/physiology , Rats , Rats, Wistar
12.
J Abdom Wall Surg ; 1: 10018, 2022.
Article in English | MEDLINE | ID: mdl-38689799

ABSTRACT

Background: Digital and Social Media (#SoMe) platforms have revolutionized the way information is shared, classified and accessed among medical professionals worldwide. The aim of this study was to review the hashtags used on Twitter by @EuroHerniaS to provide a practical roadmap for easier social media utilization for hernia surgery stakeholders. Methods: The hashtags used in tweets and retweets of the @EuroHerniaS Twitter feed were collated since its foundation in November 2016. Results: The first hashtag used was #HerniaSurgery. Since foundation to July 2021, the @EuroHerniaS Twitter feed has used 90 separate hashtags. The number of new hashtags per year was increasing leading to the development of an online library. The increasing diversity of hernia related hashtags allows for the more detailed posting and searching of hernia related information on the #SoMe platform Twitter. Conclusion: The more detailed use of hashtags on Twitter is to be encouraged. Hernia surgeons can make use of them both when posting and reviewing posts to aid the categorization of posts.

13.
Nutrients ; 13(2)2021 Feb 04.
Article in English | MEDLINE | ID: mdl-33557019

ABSTRACT

Although it is recognized that dehydration and acidification of the body may reduce the exercise capacity, it remains unclear whether the qualitative and quantitative shares of certain ions in the drinks used by players during the same exertion may affect the indicators of their water-electrolyte and acid-base balance. This question was the main purpose of the publication. The research was carried out on female field hockey players (n = 14) throughout three specialized training sessions, during which the players received randomly assigned fluids of different osmolarity and minerals contents. The water-electrolyte and acid-base balance of the players was assessed on the basis of biochemical blood and urine indicators immediately before and after each training session. There were statistically significant differences in the values of all examined indicators for changes before and after exercise, while the differences between the consumed drinks with different osmolarities were found for plasma osmolality, and concentrations of sodium and potassium ions and aldosterone. Therefore, it can be assumed that the degree of mineralization of the consumed water did not have a very significant impact on the indicators of water-electrolyte and acid-base balance in blood and urine.


Subject(s)
Acid-Base Equilibrium/physiology , Athletes , Beverages , Exercise/physiology , Minerals/administration & dosage , Water-Electrolyte Balance/physiology , Adult , Drinking/physiology , Female , Hockey , Humans , Osmolar Concentration , Young Adult
14.
Sports Health ; 13(3): 278-284, 2021.
Article in English | MEDLINE | ID: mdl-33320785

ABSTRACT

BACKGROUND: Pain is a characteristic, unpleasant sensory and emotional experience associated with actual or potential tissue damage. Pain is a subjective sensation, modulated by many factors such as age, sex, emotional state, national origin, or physical activity. Moreover, it is closely associated with intense physical activity, injuries, and traumas, which can significantly modulate pain tolerance. HYPOTHESIS: We postulate that there are correlations between past injuries, physical activity, and intensity of pain perception (pain threshold and pain tolerance) in a population of healthy men and women. STUDY DESIGN: Retrospective cohort study. LEVEL OF EVIDENCE: Level 4. METHODS: A total of 302 participants aged 18 to 32 years were included. The participants were divided into 2 groups (active and inactive individuals), in accordance with the scope of physical activity they had indicated. The test of pressure pain threshold and pressure pain tolerance was performed using an algometer. RESULTS: Active women achieved significantly higher pain threshold and pain tolerance values in all measurements on the upper limb (except for the pain threshold on the left hand) compared with inactive women. In mediation analysis, the effect of injury remained significant only for the pressure pain tolerance in the dominant arm and the left hand in the female group. In the case of men, there were no significant differences in all measurements in view of the threshold and tolerance for pain between the groups of active and inactive and between men with injuries and without injuries. CONCLUSION: Intense, regular physical activity is a factor modulating the perception of pain. This was demonstrated as lowered sensitivity to pain stimuli in a population of healthy women. CLINICAL RELEVANCE: Injuries should be treated as an important factor modulating the perception of pain. We recommend detailed monitoring of injuries during treatment and control of pain sensation.


Subject(s)
Athletic Injuries/psychology , Pain Perception/physiology , Adolescent , Adult , Exercise/psychology , Female , Humans , Male , Pain Threshold , Retrospective Studies , Sex Factors , Upper Extremity/physiology , Young Adult
16.
Article in English | MEDLINE | ID: mdl-32674282

ABSTRACT

This study assesses the status of hydration and the acid-base balance in female handball players in the Polish Second League before and after simulated matches in both indoor (hall) and beach (outdoor) conditions. The values of biochemical indicators useful for describing water-electrolyte management, such as osmolality, hematocrit, aldosterone, sodium, potassium, calcium, chloride and magnesium, were determined in the players' fingertip capillary blood. Furthermore, the blood parameters of the acid-base balance were analysed, including pH, standard base excess, lactate and bicarbonate ion concentration. Additionally, the pH and specific gravity of the players' urine were determined. The level of significance was set at p < 0.05. It was found that both indoor and beach simulated matches caused post-exercise changes in the biochemical profiles of the players' blood and urine in terms of water-electrolyte and acid-base balance. Interestingly, the location of a simulated match (indoors vs. beach) had a statistically significant effect on only two of the parameters measured post-exercise: concentration of calcium ions (lower indoors) and urine pH (lower on the beach). A single simulated game, regardless of its location, directly affected the acid-base balance and, to a smaller extent, the water-electrolyte balance, depending mostly on the time spent physically active during the match.


Subject(s)
Acid-Base Equilibrium , Sports , Water-Electrolyte Balance , Bicarbonates , Female , Humans , Osmolar Concentration , Sports/physiology , Young Adult
17.
Ann Biomed Eng ; 48(1): 133-143, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31309369

ABSTRACT

The left atrial appendage (LAA) is a small, finger-like extension of the left atrium and its exclusion is used as a treatment strategy to prevent ischemic stroke. Existing holdfast devices may damage the tissue, are unisized and not adjustable. A novel holdfast device for LAA exclusion devoid of these shortcomings was designed and 3D-printed using the Selective Laser Sintering (SLS) technology with polyamide powder and tested it on animal model. We selected the SLS 3D printing technology due to its wid14e availability and low production costs which could provide on-site 3D printing for specific patient. The purpose of this study was to evaluate the biocompatibility of the reported holdfast device and compare the histological results obtained for local tissue reactions to those obtained for an established grafting material. Thirty swine subdivided into two groups were examined. The LAA exclusion device was implanted and was either coated with a polyester vascular implant or not coated at all and the histological response to the device's presence was evaluated which is a standard approach to test the device biocompatibility. In all cases, complete occlusion was seen without any pathological findings during the incubation time. In both groups, the surface of the atrium under a holdfast device was smooth and shiny and had no clots. The foreign body reaction of the LAA holdfast device made of polyamide powder was insignificantly lower compared to the polyester graft. Thus, it fulfils the parameters of biocompatibility at the highest degree, and makes it suitable material for the manufacturing of LAA holdfast devices.


Subject(s)
Atrial Appendage/surgery , Biocompatible Materials , Cardiac Surgical Procedures/instrumentation , Prosthesis Design , Animals , Female , Foreign-Body Reaction , Male , Materials Testing , Nylons , Polyesters , Printing, Three-Dimensional , Swine
18.
Physiol Behav ; 180: 131-136, 2017 Oct 15.
Article in English | MEDLINE | ID: mdl-28844852

ABSTRACT

The aim of this study was to characterise the temperament of combat athletes in comparison to that of individuals who do not practise any sports with regard to pain sensitivity measured with the cold pressor test (CPT) and pressure pain threshold (PPT). The study involved 284 healthy men, aged 18 to 43years. The first group consisted of 198 combat athletes, including boxing (n=19), mixed martial arts (MMA) (n=97) and karate (n=82), aged from 18 to 43years. The control group consisted of 86 subjects between the ages of 18 and 26years, academic students not practising any sport professionally. Pain threshold and pain tolerance were evaluated using the CPT and a pressure algometer. Temperament was measured with the Formal Characteristics of Behaviour - Temperament Inventory (FCB-TI). The contact athletes showed much higher tolerance to pain than the control group using both tools: CPT (p=0.007) and PPT (p<0.001). In athletes, but not in controls, relationships were noted between BMI and endurance (r=0.20; p=0.004), BMI and activity (r=-0.283; p<0.001), BMI and pain threshold (r=0.15; p<0.05), and BMI and pain tolerance (r=0.30; p<0.001), when measured by the algometer - this necessitating adjustment for further analysis. The athletes and students in the study groups differed significantly with regard to intensity of four temperamental traits, but after BMI adjustments only group differences in Preservation, Sensory sensitivity and Emotional reactivity remained significant'. These differences indicate individual differences in perception and reaction to external stimuli. Significantly higher pain tolerance (CPT and PPT) in the athletes studied was related to specific psychological features. The obtained results of temperamental characteristics may indicate higher resilience of the nervous system in combat athletes in comparison to non-athletes.


Subject(s)
Athletes/psychology , Pain Threshold/physiology , Pain/psychology , Temperament/physiology , Adolescent , Adult , Humans , Hyperalgesia/physiopathology , Male , Pain/physiopathology , Pain Measurement , Personality Inventory , Physical Stimulation , Statistics, Nonparametric , Young Adult
19.
Langenbecks Arch Surg ; 402(7): 1039-1045, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28812139

ABSTRACT

PURPOSE: Although clinical examination is the gold standard for the diagnosis of groin hernia, imaging procedures can improve the detection of femoral hernias, incipient hernias, and less-common types of hernias (e.g., an obturator hernia). The aim of this study is to evaluate the sensitivity and specificity of dynamic inguinal ultrasound (DIUS). MATERIALS AND METHODS: Between July 2010 and June 2015, 4951 clinical and ultrasound examinations of the groin area were conducted at the Hanse-Hernienzentrum in Hamburg, Germany. The ultrasonographic findings were prospectively evaluated to determine the number of inguinal and femoral hernia diagnoses that were ultrasonically confirmed and also to consider cases in which clinical examination overlooked these diagnoses. The results were compared with the intraoperative findings. RESULTS: The results show that standardized ultrasound examination of the groin area with high-frequency, small-part linear transducers also serves to accurately display femoral and small or occult groin hernias. The high-level specificity (0.9980) and sensitivity (0.9758) are proof of the procedure's quality. CONCLUSIONS: To ensure high-quality hernia treatment, regular use of standardized ultrasound examinations is recommended.


Subject(s)
Hernia, Inguinal/diagnostic imaging , Ultrasonography , Adult , Female , Germany , Groin , Hernia, Inguinal/surgery , Herniorrhaphy , Humans , Male , Middle Aged , Prospective Studies , Sensitivity and Specificity
20.
J Appl Physiol (1985) ; 121(1): 164-72, 2016 07 01.
Article in English | MEDLINE | ID: mdl-27197862

ABSTRACT

The physiological role of the muscle histidyl dipeptides carnosine and anserine in contractile function of various types of muscle fibers in vivo is poorly understood. Ten adult male Wistar rats were randomly assigned to two groups: control and supplemented for 10 wk with beta-alanine, the precursor of carnosine (∼640 mg·kg body wt(-1)·day(-1)). Thereafter, contractile properties and fatigability of isolated fast fatigable (FF), fast resistant to fatigue (FR), and slow motor units (MUs) from the medial gastrocnemius were determined in deeply anaesthetized animals. The fatigue resistance was tested with a 40-Hz fatigue protocol followed by a second protocol at 40 Hz in fast and 20 Hz in slow units. In the supplemented rats, histidyl dipeptide concentrations significantly increased (P < 0.05) by 25% in the red portion of the gastrocnemius, and carnosine increased by 94% in the white portion. The twitch force of FF units and maximum tetanic force of FR units were significantly increased (P < 0.05), and the half-relaxation time was prolonged in slow units (P < 0.05). FF units showed less fatigue during the first 10 s, and FR units showed higher forces between 10 and 60 s during the 40-Hz fatigue test. In slow units, forces declined less during the first 60 s of the 20-Hz test. In conclusion, this in vivo experiment demonstrates that an elevation in muscle histidyl dipeptide content elicits beneficial changes in MU contractile characteristics and fatigue resistance. Carnosine and anserine seem to play an important yet divergent role in various MUs.


Subject(s)
Dipeptides/metabolism , Motor Neurons/physiology , Muscle Contraction/physiology , Muscle Fibers, Fast-Twitch/physiology , Muscle Fibers, Slow-Twitch/physiology , Animals , Fatigue/metabolism , Fatigue/physiopathology , Male , Motor Neurons/metabolism , Muscle Fibers, Fast-Twitch/metabolism , Muscle Fibers, Slow-Twitch/metabolism , Rats , Rats, Wistar , beta-Alanine/metabolism
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