Impact of Prolonged Cessation of Organized Team Training Due to the COVID-19 Pandemic on the Body Composition of Japanese Elite Female Wheelchair Basketball Athletes.

Studies on the effects of training confinement on athletes with physical impairments are limited. Hence, in this retrospective cohort study, we aimed to investigate the impact of prolonged cessation of organized team training due to the coronavirus disease 2019 pandemic on the body composition of elite female Japanese basketball athletes. Fourteen female wheelchair basketball athletes (aged ≥20 years) were enrolled. The primary outcomes were lean and adipose indices measured using whole-body dual-energy X-ray absorptiometry. The impact of prolonged organized team training cessation on body composition was investigated by comparing the body composition at baseline and post-training confinement. A reduced whole-body lean mass (p = 0.038) and percent lean mass (p = 0.022), as well as an increased percent body fat (p = 0.035), were observed after the confinement period. The regional analysis revealed reduced percent lean and increased percent fat masses in the trunk (p = 0.015 and p = 0.026, respectively) and upper limbs (p = 0.036 and p = 0.048, respectively). In conclusion, prolonged organized team training cessation reduced lean mass and increased body fat percentage, primarily in the trunk and upper limbs. Individualized training programs targeting these body regions should be implemented to improve body composition and physical conditions in athletes during and after prolonged cessation of organized team training.

Evaluation of hand functions and distal radioulnar joint instability in elite wheelchair basketball athletes: a cross-sectional pilot study.

BACKGROUND: Wrist injury affects wheelchair basketball players' performance; however, the relationship between distal radioulnar joint (DRUJ) instability and hand functions is unclear. This cross-sectional pilot study investigated DRUJ instability in elite female wheelchair basketball athletes using force-monitor ultrasonography. METHODS: Nine elite female wheelchair basketball athletes (18 wrists) were included in the study. A triangular fibrocartilage complex (TFCC) injury was confirmed using magnetic resonance imaging (MRI). Hand functions were evaluated based on the range of motion (ROM) of wrist palmar flexion, dorsiflexion, radial deviation, and ulnar deviation; grip strength; arm circumference; forearm circumference; and DRUJ instability or pain using the ballottement test. The Mann-Whitney U test was used to compare parameters between the TFCC-injured and intact wrists. Radioulnar displacement was measured using force-monitor ultrasonography and pressure data, and the displacement-to-force ratio was used as an indicator of DRUJ instability. The correlation between the DRUJ displacement-to-force ratio and each hand function assessment was evaluated using Pearson correlation coefficient for the TFCC-injured and intact wrists. A generalized linear mixed model (GLMM) was used to estimate the relationship between hand functions and DRUJ instability. RESULTS: TFCC injuries in seven wrists were confirmed using MRI findings (38.9%). The ulnar deviation ROM values of the TFCC-injured wrist (n = 7) and intact (n = 11) groups were 38.6 ± 8.0° and 48.6 ± 7.8°, respectively. The ulnar deviation ROM was significantly smaller in the TFCC-injured wrists (p = 0.02, r = - 0.54). In the TFCC-injured wrists, no correlation was observed between the displacement-to-force ratio and the hand function assessment. In contrast, the displacement-to-force ratio negatively correlated with grip strength, arm circumference, and forearm circumference in the intact wrists (Pearson correlation coefficient r = - 0.78, - 0.61, and - 0.74, respectively). The GLMM showed that the displacement-to-force ratio significantly affected grip strength, arm circumference, and forearm circumference in the intact group. CONCLUSIONS: In intact wrists, correlations were observed between hand functions such as upper arm/forearm strength and DRUJ stability evaluated using ultrasound. Maintaining and strengthening grip strength, forearm circumference, and arm circumference are associated with DRUJ stability and may be related to TFCC injury prevention in wheelchair basketball athletes. TRIAL REGISTRATION: The protocol was registered with the UMIN Clinical Trials Registry (UMIN000043343) [Date of first registration: 16/02/2021].

Associations between wheelchair user's shoulder pain index and tendinitis in the long head of the biceps tendon among female wheelchair basketball players from the Japanese national team.

BACKGROUND: Among injuries in wheelchair athletes, shoulder injury is the most common. An easy and valid assessment tool is required to monitor the shoulder status in wheelchair athletes anytime. The present study aimed to investigate the association of wheelchair user's shoulder pain index (WUSPI) with physical examinations for tendinitis in the long head of the biceps tendon (LHBT) and range of motion (ROM) of shoulder movements among female wheelchair basketball players from the Japanese national team. METHODS: A total of 21 female players (mean age, 32.0 ± 7.9 years) participated in this study. LHBT tendinitis was assessed using findings of tenderness in the bicipital groove point (TBGP) and speed test. Shoulder ROMs were evaluated in three movements-namely, abduction, flexion, and extension. RESULTS: The mean total WUSPI score was 9.55 ± 13.35 points. The players were more likely to experience shoulder pain during activities related to wheelchair pushing and object lifting. A higher total WUSPI score was strongly and moderately associated with positive findings of TBGP (effect size r = 0.82) and speed test (r = 0.49), respectively. Furthermore, the total WUSPI score was significantly associated with limited ROM in shoulder abduction (r = 0.47) and flexion (r = 0.43). Receiver operating characteristic analysis showed that the total WUSPI score had a significant area under the curve (AUC) for positive findings of TBGP (AUC = 0.98), speed test (AUC = 0.83), and limited ROM in abduction (AUC = 0.84). When optimal cut-points were set by the Youden index, total WUSPI scores of 4.1 points (sensitivity = 1.00, specificity = 0.92), 11.3 points (sensitivity = 0.80, specificity = 0.81), and 3.3 points (sensitivity = 1.00, specificity = 0.65) were recommended for screening positive findings of TBGP, speed test, and limited ROM in abduction, respectively. CONCLUSION: TBGP, which is a major finding of LHBT tendinitis, was strongly associated with the total WUSPI score in physical examinations. Hence, pain assessed by WUSPI could reflect the presence of LHBT tendinitis. The WUSPI is a superior tool for monitoring the shoulder status of wheelchair basketball players.

Safety and Efficacy of Ranibizumab and Luseogliflozin Combination Therapy in Patients with Diabetic Macular Edema: Protocol for a Multicenter, Open-Label Randomized Controlled Trial.

INTRODUCTION: Diabetic macular edema (DME) threatens daily life activities such as reading and driving and reduces the patients' quality-of-life. Recently, anti-vascular endothelial growth factor (VEGF) agents have become a first-line therapy in DME. However, therapy with anti-VEGF agents has several problems: repeated invasive injections are required; medical costs are high; and a certain proportion of patients with DME are resistant to treatment with anti-VEGF agents. While sodium-glucose co-transporter 2 (SGLT2) inhibitors have been widely used for the treatment of type 2 diabetes mellitus (T2DM), the effects of a combination therapy with anti-VEGF agent and SGLT2 inhibitor on DME are not yet known. METHODS: This study enrolls subjects with T2DM and DME, randomizes them into either a study agent treatment group (treated with ranibizumab as anti-VEGF agent and luseogliflozin as SGLT2 inhibitor) or a control group (treated with ranibizumab and glimepiride), and observes the subjects for 52 weeks after initiation of treatment. Planned outcomes: The primary endpoint is intergroup difference in the number of intravitreal anti-VEGF injections to the study eye from baseline to week 48. Secondary and exploratory endpoints include safety and ophthalmologic and internal medical clinical parameters. REGISTRATION: This study is registered at the University Hospital Medical Information Network Clinical Trial Registry (UMIN000033961) and Japan Registry of Clinical Trials (jRCTs031180210).

Influence of Functional Classification on Skill Tests in Elite Female Wheelchair Basketball Athletes.

Background and objectives: Wheelchair basketball players are classified into four functional classes according to the player's "volume of action", characterized by trunk movement and stability. As this classification is based on a kinematic point of view, test items might be differentially affected by the functional classification level. We aimed to clarify field-based skill test items closely related to the functional classification level. Materials and Methods: Twenty-six female wheelchair basketball athletes (Japan National Team candidates) completed seven field-based skill tests (20 m sprint, agility T-test, figure-eight with a ball test, the Yo-Yo 10 m recovery test, and three types of maximal passes), and anthropometric measurements were applied. Results: Significant differences among the classification levels were found for one-hand maximal passes (baseball and hook passes) and the figure-eight with a ball test. Furthermore, performance in the 20 m sprint and 10 m Yo-Yo recovery tests significantly differed between classes 1 and 4. Conclusions: The test items most influenced by the classification levels were one-hand passes, which require trunk stability and balance not only in the horizontal plane, but also in the sagittal and frontal planes. Coaches should consider which test items are strongly affected by the functional classification level when assessing a player's performance.

Investigation of the Female Athlete Triad in Japanese Elite Wheelchair Basketball Players.

Background and objectives: Para-sports have become increasingly competitive, necessitating greater physical activity; secondary disorder prevention is therefore crucial. Among secondary disorders, the female athlete triad (FAT) is defined as low energy availability (EA), menstrual dysfunction, and low bone mineral density (BMD); although studied in able-bodied athletes, reports on female para-athletes are scarce. We retrospectively investigated the FAT in wheelchair basketball players in the Japanese national team. Materials and Methods: Thirteen female wheelchair basketball players (mean age: 28.9 ± 8.1 years) were enrolled. The medical history (underlying diseases, gynecological disorders, and stress fractures), athletic and sport-specific parameters (wheelchair basketball classification, and wheelchair usage conditions), hematological status (hemoglobin, iron, estradiol, progesterone, total P1NP, and TRACP-5b levels), nutritional status (total energy, protein, calcium, and iron intake), body composition (BMD and lean body mass (LBM)), and EA were assessed. Results: Two (15.4%) had pertinent gynecological histories and six (46.2%) had menstrual cycle disorders. Three (23.1%) experienced excessive menstrual flow and nine (69.2%) had menstrual pain. No stress fractures were reported. All laboratory data were within normal limits. Total energy and iron intakes based on age-specific requirements were 99.8% and 59.8%, respectively. Iron and hemoglobin levels correlated with menstrual flow (ρ = -0.63, p = 0.019 and ρ = -0.56, p = 0.046, respectively). The mean total BMD was 109.2%, and the mean EA (41.4 kcal/kg LBM) was lower than recommended levels. The leg BMD in spinal disorders was significantly lower than that in skeletal disorders (p = 0.003). The arm LBM was higher (150.6%) than that of age-matched controls. Conclusion: Among female wheelchair basketball players with FAT, the total BMD was comparable to that of age-matched controls; however, leg BMD in spinal disorders was significantly lower than that in skeletal disorders. Players with heavy menstrual flow had lower hemoglobin and iron levels. Further research is needed on the FAT to optimize health and sports performance among para-athletes.

Contributions to the team score by male wheelchair basketball players with different physical capacities at the Rio 2016 Paralympics.

[Purpose] The contributions of male wheelchair basketball players with different capability classifications to the team score at the Rio 2016 Paralympics were evaluated. The roles required for team members belonging to each such classification were determined. [Participants and Methods] Statistics obtained from the official box scores of all 42 games included at the Rio 2016 Paralympics were used in this study. Players who participated for >20 minutes in each game were included in the analysis. Players were divided into 3 groups (low, middle, and high) based on their capability classification. The mean statistical data related to each group were compared, and the covariance structure was analyzed to determine the role of each player group. [Results] Many statistical values were higher in players belonging to the high group. In the high group, the relevant variables were field goals scored, field goals attempted, assists, and turnovers. In the low group, the relevant variables were field goals scored, steals, and turnovers. [Conclusion] Many plays related to the ball depended on the high group. High-group players are required to demonstrate strong scoring ability and to reduce turnovers. Conversely, low-group players should increase the numbers of field goals made, increase steals, and reduce turnovers.

Difference in contributions to the team's score in female wheelchair basketball at the 2016 Rio Paralympics by physical capability classification.

[Purpose] This study clarified differences in players' contributions to the team's score in female wheelchair basketball at the 2016 Rio Paralympics by physical capacity classification, and examined the roles required in the team. [Subjects and Methods] This study used stats (record of play contents) for players who played for more than 20 minutes from the official box scores of all 31 games at the 2016 Paralympics. Players were divided into three groups by physical capacity classification: low, middle, and high. The average stats for each group were compared and the covariance structure was analyzed to determine the role of each group during the game. [Results] Comparisons showed that the higher the class, the higher the value of many stats items. Important elements were defensive rebound, steal, and turnover in the low group; and score, offensive rebound, and turnover in the high group. [Conclusion] Players in the high group have more plays related to the ball. Those in the low group should increase the numbers of steals and defensive rebounds and reduce turnover. High group players are required to have scoring ability, acquire offensive rebound, and reduce turnover.

A survey of deep tissue injury in elite female wheelchair basketball players.

OBJECTIVE: To investigate deep tissue injuries (DTIs) in elite female wheelchair basketball players and identify factors associated with their occurrence. METHODS: Study participants were 22 female wheelchair basketball players on the Japanese national team. The sacral and bilateral ischial regions of each participant were examined using ultrasonography to detect DTIs. RESULTS: DTIs were found in 15 players (68.2%). DTIs were more frequent in players with a central nervous system disorder (CNSd) (85.7%) than in those with skeletal system disease (SSd) (37.5%, p = 0.020), and in players using a wheelchair in daily life (84.6%) than those using a wheelchair only for basketball (44.4%, p = 0.046). Players with pelvic instability were more likely to have DTIs (90.9% vs. 45.5%, p = 0.017). DTIs were deeper in the ischial region than the sacral region (p = 0.022). Players with CNSd had more DTIs in sacral regions (90% vs. 10%, p = 0.014). Players with DTIs had lower systolic blood pressure (sBP), red blood cell (RBC) count, and serum creatinine levels (sCr) (all p < 0.05). CONCLUSIONS: Ischial DTIs were deeper than sacral DTIs. Players with CNSd had more sacral DTIs than those with SSd. CNSd, wheelchair use in daily life, pelvic instability, and lower sBP, RBC, and sCr increased the risk of DTIs.

Associations between changes in the maternal gut microbiome and differentially methylated regions of diabetes-associated genes in fetuses: A pilot study from a birth cohort study.

Several intrauterine environmental factors can increase the future risk of type 2 diabetes. The microbiome can influence the balance between health and disease. However, the influence of the maternal gut microbiome on the future risk of diabetes in the fetus is unknown. The present study investigated the associations between maternal gut microbiome and differentially methylated regions of diabetes-associated genes in umbilical cord samples. The present study included 10 pregnant participants from a birth cohort study. 16S ribosomal ribonucleic acid metagenome analysis of maternal stool samples and deoxyribonucleic acid methylation assays of umbilical cord samples were carried out. The present study found that changes in the UBE2E2 and KCNQ1 methylation rates in umbilical cord samples were associated with the proportion of Firmicutes in the maternal gut, albeit with marginal correlations after adjustment for age and body mass index. These findings suggest a link between the methylation of diabetes-associated genes in fetuses and maternal microbiota components during pregnancy.

Correlates of shoulder pain in wheelchair basketball players from the Japanese national team: A cross-sectional study.

OBJECTIVE: To reveal correlates of shoulder pain in wheelchair basketball players from the Japanese national team. METHODS: Study participants were 19 males (29.7 ± 5.2 years) and 21 females (29.0 ± 8.2 years) players. We assessed shoulder pain using the wheelchair user's shoulder pain index (WUSPI). As potential correlates of shoulder pain, age, ability class, practice time and years of experience in wheelchair basketball were collected. RESULTS: The total WUSPI score for men (16.18 ± 17.39 points) was significantly higher than that for women (8.62 ± 15.70 points). In men, higher age was significantly correlated with greater shoulder pain for total WUSPI score and on two WUSPI items. Lower ability in wheelchair basketball was correlated with men's greater shoulder pain on three WUSPI items. In men, there were also significant correlations between longer years of experience and greater shoulder pain for total WUSPI score and on three WUSPI items. For women, there were significant correlations between longer practice time and less pain for total WUSPI score and on four WUSPI items. CONCLUSIONS: Because top male wheelchair basketball players have a higher risk of shoulder pain than female players, daily care of shoulder and periodic medical checkups are needed, especially for older male players with lower ability and more experience.

Unsuppressed lipolysis in adipocytes is linked with enhanced gluconeogenesis and altered bile acid physiology in Insr(P1195L/+) mice fed high-fat-diet.

High-fat diet (HFD) triggers insulin resistance and diabetes mellitus, but their link remains unclear. Characterization of overt hyperglycemia in insulin receptor mutant (Insr(P1195L/+)) mice exposed to HFD (Insr(P1195L/+)/HFD mice) revealed increased glucose-6-phosphatase (G6pc) expression in liver and increased gluconeogenesis from glycerol. Lipolysis in white adipose tissues (WAT) and lipolysis-induced blood glucose rise were increased in Insr(P1195L/+)/HFD mice, while wild-type WAT transplantation ameliorated the hyperglycemia and the increased G6pc expression. We found that the expressions of genes involved in bile acid (BA) metabolism were altered in Insr(P1195L/+)/HFD liver. Among these, the expression of Cyp7a1, a BA synthesis enzyme, was insulin-dependent and was markedly decreased in Insr(P1195L/+)/HFD liver. Reduced Cyp7a1 expression in Insr(P1195L/+)/HFD liver was rescued by WAT transplantation, and the expression of Cyp7a1 was suppressed by glycerol administration in wild-type liver. These findings suggest that unsuppressed lipolysis in adipocytes elicited by HFD feeding is linked with enhanced gluconeogenesis from glycerol and with alterations in BA physiology in Insr(P1195L/+)/HFD liver.

Dexmedetomidine suppresses long-term potentiation in the hippocampal CA1 field of anesthetized rats.

PURPOSE: The aim of this study was to evaluate the effect of dexmedetomidine (DEX) on hippocampal synaptic activity in vivo. METHODS: The adult rats used for this study received a intraperitoneal bolus injection of 3, 10, 30, or 100 µg/kg of DEX or an equivalent volume of saline. Electrophysiological recording of the hippocampal CA1 region was initiated 20 min after drug administration. The results are expressed as the percentages of the population spike amplitude measured just before high-frequency stimulation (HFS). The electrophysiological data were analyzed with an area under the curve (AUC) of 10-60 min after HFS. Moreover, to investigate the sedative dose of DEX in rats, we recorded the duration of loss of spontaneous movement after the administration of each dose of DEX. RESULTS: Intraperitoneal administration of DEX at doses of 30 and 100 µg/kg induced a range of sedative effects. The AUC measurements were significantly lower in the 30 and 100 µg/kg groups than in those injected with vehicle (vehicle: 8.81 ± 0.49, n = 7; DEX 30 µg/kg: 6.02 ± 0.99, n = 6; DEX 100 µg/kg: 5.10 ± 0.43, n = 5; P < 0.05). CONCLUSION: The results of our in vivo study reveal that sedative doses of DEX impaired the induction of hippocampal long-term potentiation (LTP). These findings may signify a causal link between DEX-induced sedative action and hippocampal LTP suppression, providing a better understanding of the mechanisms underlying the DEX-induced sedative and/or amnestic effect.

Bronchospasm induced by ethanol injection for a craniofacial venous malformation.

Ethanol sclerotherapy is a first-line treatment for low-flow vascular malformations. Although many complications of ethanol sclerotherapy have been described in the literature, bronchospasm is uncommon. We present a case of a patient in whom bronchospasm was precipitated by injection of ethanol during percutaneous sclerotherapy for craniofacial venous malformations that occurred during general anesthesia. The evidence for ethanol-induced bronchospasm is discussed.

Neonatal exposure to sevoflurane causes significant suppression of hippocampal long-term potentiation in postgrowth rats.

BACKGROUND: The inhaled anesthetic sevoflurane is commonly used for neonates in the clinical setting. Recent studies have indicated that exposure of neonatal rodents to sevoflurane causes acute widespread neurodegeneration and long-lasting neurocognitive dysfunction. Although acute toxic effects of sevoflurane on cellular viability in the hippocampus have been reported in some studies, little is known about the effects of neonatal sevoflurane exposure on long-term hippocampal synaptic plasticity, which has been implicated in the processes of learning and memory formation. Our study is the first to examine the long-term electrophysiological impact of neonatal exposure to a clinically relevant concentration of sevoflurane. METHODS: On postnatal day 7, rats were exposed to sevoflurane (1% or 2% for 2 hours) with oxygen. To eliminate the influence of blood gas abnormalities caused by sevoflurane-induced respiratory suppression, a group of rats were exposed to a high concentration of carbon dioxide (8% for 2 hours) to duplicate respiratory disturbances caused by 2% sevoflurane exposure. RESULTS: Exposure of neonatal rats to 2% sevoflurane for 2 hours caused significant suppression of long-term potentiation (LTP) induction in the postgrowth period. There was no significant difference between the control group and the CO2-exposed group in LTP induction, indicating that sevoflurane-induced LTP suppression was not caused by blood gas abnormalities. CONCLUSION: Our present findings indicate that neonatal exposure to sevoflurane at a higher concentration can cause alterations in the hippocampal synaptic plasticity that persists into adulthood.

Neonatal exposure to high concentration of carbon dioxide produces persistent learning deficits with impaired hippocampal synaptic plasticity.

Although respiratory complications with blood gas abnormalities contribute significantly to neurodevelopment in the immature brain, little is known about the mechanisms via which blood gas abnormalities, such as hypoxic hypercapnia, impair neurocognitive outcomes. To investigate the possible long-term consequences of neonatal exposure to hypoxic hypercapnia regarding learning ability, we investigated the effect of neonatal hypoxic hypercapnia on later functions in the hippocampus, which is a structure that has been implicated in many learning and memory processes. Neonatal rat pups (postnatal day 7; P7) were exposed to a high concentration of carbon dioxide (CO2; 13%) for 2 or 4h. Exposure to CO2 in P7 rat pups caused blood gas abnormalities, including hypercapnia, hypoxia, and acidosis, and disrupted later learning acquisition, as assessed in 10-week-old adult rats subjected to a Morris water maze test. Induction of long-term potentiation (LTP) in the synapses of the hippocampal CA1 area was also impaired, whereas the paired-pulse responses of population spikes exhibited a significant increase, in CO2-exposed rats, suggesting decreased recurrent inhibition in the hippocampus. Such long-lasting modifications in hippocampal synaptic plasticity may contribute to the learning impairments associated with perinatal hypoxic hypercapnia and acidosis.

The anti-ulcer agent, irsogladine, increases insulin secretion by MIN6 cells.

Insulin secretion by pancreatic islets is a multicellular process. In addition to other essential systems, gap junctions are an important component of cell-to-cell communication in pancreatic islets. It is well known that dysfunction of gap junctions causes inappropriate insulin secretion. The anti-ulcer agent, irsogladine, increases gap junctions in some cell types. To examine the effect of irsogladine on insulin secretion, we investigated insulin secretion by MIN6 cells treated with or without irsogladine. The expression of connexin 36 proteins and intracellular cAMP levels were also determined using immunoblotting and ELISA assays, respectively. Irsogladine had no effect on insulin secretion under 5.6mM glucose conditions. However, under 16.7 mM glucose conditions, irsogladine (1.0 × 10(-5)M) induced a 1.7 ± 0.20 fold increase in insulin secretion compared to the control (P<0.05). This effect of irsogladine on insulin secretion was inhibited by the addition of the gap junction inhibitor 18-beta-glycyrrhetinic acid. Irsogladine treatment increased the protein level of connexin 36 in the plasma membrane fraction. The intracellular cAMP level in MIN6 cells was significantly, but mildly, increased by irsogladine treatment. Furthermore, Rp-cAMP and H89 inhibited the effects of irsogladine on insulin secretion under high glucose conditions. Irsogladine increases insulin secretion under high glucose conditions. The up-regulation of gap junction channels and the increased level of intracellular cAMP induced by irsogladine treatment suggest that these phenomena are involved in irsogladine-induced increased insulin secretion.

Neonatal administration with dexmedetomidine does not impair the rat hippocampal synaptic plasticity later in adulthood.

BACKGROUND AND OBJECTIVE: The use of dexmedetomidine (DEX), a selective alpha-2 agonist, in pediatric practice is expanding as a result of its desirable properties. To clarify the long-term neurological consequences of neonatal administration of DEX, we investigated the long-term effects of neonatal administration of DEX on hippocampal synaptic activity. METHODS: The rat pups received a bolus intraperitoneal injection of either 5 or 10 µg·kg(-1) DEX, or an equivalent volume of vehicle on postnatal day 7 (P7). Nine weeks after administration, evoked potentials (population spike, PS) and long-term potentiation (LTP) in the hippocampal CA1 region of rats were studied in vivo. RESULTS: Dexmedetomidine had a considerable sedative effect at these doses with little respiratory depression on P7. Nine weeks after administration of DEX, the amplitude of PS in the two treated groups was similar to that in the control group. DEX-treated rats showed no impairment in the induction of LTP. Furthermore, the response in PS to the paired stimuli was not impaired by neonatal administration of DEX. CONCLUSION: These findings demonstrate that a single administration of DEX to rats on P7 preserves hippocampal synaptic plasticity as well as synaptic transmission later in life. In view of the some evidence that have demonstrated the permanent detrimental impact of commonly used anesthetics on neurological outcomes after neonatal exposure, our findings may suggest the relative safety of DEX administered as a sedative agent to neonatal animals with regard to the development of hippocampal synaptic functions.

Long-lasting effects of neonatal pentobarbital administration on spatial learning and hippocampal synaptic plasticity.

Exposure of newborn rats to antiepileptics such as barbiturates has long-lasting detrimental effects on the hippocampus and hippocampus-dependent behavior. However, the long-term consequences of neonatal administration with barbiturates on the hippocampal synaptic plasticity remain unresolved. In this study, we investigated the long-lasting effects of a neonatal administration of pentobarbital on spatial memory, paired-pulse plasticity in the population spikes, and long-term potentiation (LTP) in the hippocampal CA1 region of rats in vivo. Eight weeks after administration of pentobarbital (10 or 20mg/kg) on the seventh postnatal day (P7), rats showed impaired induction in LTP. During paired-pulse stimulation, pentobarbital-treated rats exhibited a greater facilitation of the test pulse population spike, suggesting a disruption in the inhibitory GABAergic synaptic transmission. Spatial learning in hidden platform task of the Morris water maze was impaired in pentobarbital-treated rats. Our present findings indicate that neonatal treatment with pentobarbital causes alterations in function of the hippocampal inhibitory synaptic transmission that persist into adulthood, likely contributing to the long-lasting abnormalities in the hippocampal LTP as well as learning ability. We also demonstrated significant respiratory disturbances, i.e., severe hypoxia, hypercapnia, and extracellular acidosis, in rats treated with pentobarbital on P7. Given that extracellular acidosis can also modulate synaptic transmission in the developing hippocampus, this finding led us to speculate regarding the influence of respiratory disturbances in pentobarbital-induced long-lasting hippocampal dysfunctions.