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Duchenne muscular dystrophy (DMD) is a progressive muscular disorder caused by X-chromosomal DMD gene mutations. Recently, a new CRISPR/Cas9-mediated DMD rat model (cDMDR) was established and is expected to show cardiac lesions similar to those in humans. We therefore investigated the pathological and pathophysiological features of the cardiac lesions and their progression in cDMDR. For our cDMDR, Dmd-mutated rats (W-Dmd em1Kykn ) were obtained. Dmd heterozygous-deficient females and wild-type (WT) males were mated, and male offspring including WT as controls were used. (1) Hearts were collected at 3, 5, and 10 months of age, and HE- and Masson's trichrome-stained specimens were observed. (2) Electrocardiogram (ECG) recordings were made and analyzed at 3, 5, and 8 months of age. (3) Echocardiography was performed at 9 months of age. In cDMDR rats, (1) degeneration/necrosis of cardiomyocytes and myocardial fibrosis prominent in the right ventricular wall and the outer layer of the left ventricular wall were observed. Fibrosis became more prominent with aging. (2) Lower P wave amplitudes and greater R wave amplitudes were detected. PR intervals tended to be shorter. QT intervals were longer at 3 months but tended to be shorter at 8 months. Sinus irregularity and premature ventricular contraction were observed at 8 months. (3) Echocardiography indicated myocardial sclerosis and a tendency of systolic dysfunction. Pathological and pathophysiological changes occurred in cDMDR rat hearts and progressed with aging, which is, to some extent, similar to what occurs in humans. Thus, cDMDR could be a valuable model for studying cardiology of human DMD.

This study assessed the feasibility of using a vegetable extract, MGM-P (quebracho tannin product), as an alternative to antibiotics for weaned piglets, it investigated MGM-P effects on growth performance, diarrhea, and overall health in early-weaned piglets. In total, 24 piglets were allocated to three treatment groups fed basal diets supplemented with 0, 0.2%, or 0.3% MGM-P for 20 days. The addition of 0.3% MGM-P to the diet of early-weaned piglets improved diarrhea incidence, hematological parameters, and intestinal mucosa structure. Furthermore, the addition of 0.2% or 0.3% MGM-P to the diet of early-weaned piglets did not affect their overall health. Importantly, MGM-P had no effects on average daily gain (ADG), average daily feed intake (ADFI), or feed conversion ratio (FCR). Gut morphology analysis showed that treatment with 0.3% MGM-P enhanced the jejunal villus height (p &lt, 0.05) while reducing the ileal crypt depth (p &lt, 0.05) and colon mucosal thickness (p &lt, 0.05). Collectively, the findings suggested that the use of MGM-P as an alternative to dietary antibiotics could improve diarrhea incidence in early-weaned piglets without negative effects on growth performance or overall health.

The senescence-accelerated mouse (SAM) strain has been established as an inbred strain with an accelerated aging phenotype. SAM prone-8 (SAMP8), one of the SAM strain, exhibits learning disability, immune deficiency, and circadian rhythm loss at a relatively young age. However, it has not been clarified whether aging affects the autonomic nervous activity in SAMP8. The aim of this study was to clarify the utility of SAMP8 in age-related studies of autonomic nervous function. Electrocardiogram (ECG), body temperature, and locomotor activity were recorded to evaluate bio-behavioral activities. Autonomic nervous activity was evaluated via power spectral analysis of heart rate variability from ECG recordings. SAMP8 significantly decreased both biological and autonomic nervous functions, and the animals exhibited circadian rhythm loss of locomotive activity at as early as 40 weeks of age compared with a control strain at the same age. We concluded that the SAMP8 strain can be used as an animal model for age-related studies of autonomic nervous function.

Autonomic nervous function evaluated by heart rate variability (HRV) and blood characteristics were compared between Holstein Friesian cows that developed postpartum fever (PF; n = 5) and clinically healthy (CH; n = 6) puerperal cows in this case-control study. A cow was defined as having PF when its rectal temperature rose to ≥39.5°C between 1 and 3 days postpartum. We recorded electrocardiograms during this period using a Holter-type electrocardiograph and applied power spectral analysis of HRV. Comparisons between the groups were analyzed byttest or Mann-WhitneyUtest, and the relationship between rectal temperature and each parameter was analyzed using multiple regression analysis. Heart rate was higher in PF cows than in CH cows (Mean ± SE, 103.3 ± 2.7 vs. 91.5 ± 1.7 bpm). This result suggested that PF cows had a relatively dominant sympathetic nervous function. Total (44,472 ± 2,301 vs. 55,373 ± 1,997 ms) and low frequency power (24.5 ± 3.8 vs. 39.9 ± 5.3 ms) were lower in PF cows than in CH cows. These findings were possibly caused by a reduction in autonomic nervous function. The total white blood cell count (54.3 ± 5.1 vs. 84.5 ± 6.4 ×102/μL) and the serum magnesium (2.1 ± 0.1 vs. 2.4 ± 0.1 mg/dL) and iron (81.5 ± 8.0 vs. 134.4 ± 9.1 μg/dL) concentrations were lower and the serum amyloid A concentration (277 ± 33 vs. 149 ± 21 μg/mL) was higher in PF cows than in CH cows. These results imply that more inflammation was present in PF cows than in CH cows. Multiple regression analysis showed that both of low frequency power and concentration of serum iron were associated with rectal temperature. We found differences in changes in hematologic results, biochemical findings, and HRV patterns between PF cows and CH cows.

Cardiotoxicity is a concern in the development of microtubule-disassembling agents (MDAs) as vascular-disrupting agents of tumors. This study investigated cardiotoxicity in rats induced by a single-dose of combretastatin A4 disodium phosphate (CA4DP), an MDA and discussed the use of this rat model in nonclinical studies of MDAs. First, CA4DP (120 mg/kg) was administered to rats intravenously, and cardiac histopathology and blood biomarkers were examined after 0.5, 24, and 72 h. Next, CA4DP (120 mg/kg) was administered to rats intravenously, and the electrocardiography and echocardiography results were analyzed. The results showed that at 0.5 h after dosing, plasma creatine kinase (CK), CK-muscle/brain (CK-MB), and fatty acid binding protein 3 levels increased. At 24 h, lactate dehydrogenase (LDH)-1, CK, and CK-MB levels increased, and multifocal vacuolar degeneration of myocardial cells was observed in the apical inner layer. At 72 h, LDH-1 levels were increased, and multifocal myocardial necrosis was observed in the interventricular septum and inner layer of the apex of left ventricular wall. Furthermore, at 0.5 h, heart rate (HR), ejection fraction (EF), and cardiac output (CO) decreased. At 24 h, CO decreased. Finally, at 72 h, HR, EF, and CO decreased, and depression of the T-wave amplitude was observed. In conclusion, myocardial injury, bradycardia, and depressed cardiac function were induced in rats by a single-dose of CA4DP. The lesion distribution and electrocardiographic features suggested that myocardial injury was induced by ischemia. These findings are similar to MDA-induced cardiotoxicity in humans, and this rat model will prove useful in studies of the cardiotoxicity in humans.

The present study aims to examine the effect of tropical temperatures on autonomic nervous activity in Cambodian dairy cattle by analyzing heart rate variability (HRV). Holter-type electrocardiograms were recorded in adult crossbred cows (Cambodian native × Holstein) either in a sheltered area or under direct sunlight. Rectal temperatures and heart rates increased in animals under direct sunlight as compared to those in the shelter. The power spectral analysis of HRV revealed that three out of the five cows studied underwent a decrease in parasympathetic nervous activity under direct sunlight with the remaining two cows showing no apparent change. The HRV analysis would prove to be a useful tool to reveal information about heat tolerance in dairy cows.

Ovarian follicular development was monitored daily by transrectal ultrasonographic examination in 20 female goats for 2 successive estrous cycles (40 cycles). These animals exhibited ovulatory cycles with a mean length of 20.8 ± 1.1 days. The mean number of follicles ovulated was 2.3 ± 0.9 and their diameter before ovulation was 6.9 ± 1.1 mm. Among 40 estrous cycles examined, 9 (23 %) displayed 1 latent follicular wave and the remaining 31 (77 %) cycles displayed 2 latent follicular waves. Three and 4 days after the second spontaneous ovulation (day 0 = ovulation), when diameter of dominant follicles of the first latent wave exceeded 5.5 mm, 20 goats were treated with a luteolytic dose of prostaglandin F2a (PGF2a) and randomly assigned to one of three groups. This treatment immediately decreased plasma levels of progesterone and increased those of estradiol, resulting in ovulation 2 or 3 days later. One group of goats (n = 5) treated with PGF2a at the first latent follicular wave and was mated with fertile male goat, resulting in 4 pregnancies. For the second group of goats (n = 5), 4 successive short estrous cycles were induced. A total of 35 short ovulatory cycles were induced at a mean interval of 6.5 ± 1.2 days with a range of 4–9 days. Five of goats were allowed to mate following 4 consecutive short ovulatory cycles; normal oestrous behavior was observed at each estrus. The goats were successfully mated, became pregnant and delivered kids of normal body weight and length. The remaining goats (n = 6), in addition to PGF2a treatment, received exogenous progesterone supplement which allowed latent follicular development to occur, but prevented ovulation until the effect of progesterone supplement subsided. Thus, it was concluded that appropriate phase of follicle size and progesterone concentration could control ovulation of ruminant animal.

Environmental enrichment (EE) can reduce anxiety and stress in experimental animals, while little is known about the influence on autonomic nervous activity especially in disease animal models. Diabetes mellitus (DM) is associated with cardiovascular autonomic dysfunction, which can be characterized by a higher resting heart rate and a lower heart rate variability (HRV). We hypothesized that EE can enhance parasympathetic nervous activity while reducing disease progression in type 2 diabetic mice. A telemetry transmitter was implanted in NSY mice to continuously record electrocardiograms (ECG). Animals were kept in a cage with or without a nest box as EE. The autonomic nervous activity was evaluated using power spectral analysis of HRV. Four weeks of EE could increase high frequency (HF) power, but no change was observed in the absence of EE. Although animals showed impaired glucose tolerance at 48 weeks of age regardless of EE, a worsen case was observed in control. These results indicate that EE can be necessary for long-term housing of experimental animals and may reduce the risk of impaired glucose tolerance in NSY mice by enhancing parasympathetic nervous activity. In future, it is demanded whether increasing parasympathetic nervous activity, whatever the method is, can prevent diabetes from worsening.

On June 28, 2011, 26 pigs were rescued from the alert area, 17 km northwest of the Fukushima Daiichi Nuclear Power Plant, where radiation levels were approximately 1.9–3.8 μSv/h. The pigs were transferred outside of the radiation alert area to the Animal Resource Science Center (ARSC), The University of Tokyo. It was confirmed by the farm owner that the pigs were never fed radiation-contaminated concentrate and they had access to uncontaminated groundwater (http://www.env.go.jp/press/press.php?serial=16323) while living inside the radiation alert area; however, radiocesium was detected in the rescued pigs’ organs, testis/ovary, spleen, liver, kidney, psoas major, urine, and blood, within nine months after the nuclear disaster. Radiocesium levels in samples collected in early January 2012 were significantly lower than those collected in either early or late September 2011, indicating a continuing decrease in radiation levels over that duration. Radiocesium was not detected in organs collected in August 2012. In September 2011, the authors of the present study visited a local farm to collect samples from pigs who remained inside the radiation alert area. Radiocesium concentration in these pigs was nearly ten times higher than from the rescued pigs.

Because we found that WTC rats might be resistant to streptozotocin (STZ), we have elucidated the mechanisms of resistant to the diabetogenic effects of STZ in the WTC rats. Dose response to STZ was evaluated with glucose levels. No significant changes in glucose level to STZ administration were observed in WTC rats. Insulin secretion by suppling glucose was preserved in WTC rats even after STZ administration. Although there was no significant difference in gene expression of both GLUT2 and Kir6.2, which were involved in STZ resistance, between WTC rats and Wistar rats, the expression of metallothionein 2a in pancreas and liver to STZ administration of WTC rats was significantly higher than that of Wistar rats. Moreover, alloxan did not induce diabetes in WTC rats as same as STZ. These results suggest that WTC rats might have powerful antioxidant property to protect β cells in pancreas. Because the STZ-resistant property is very close characteristics to human beings, WTC rats will become a useful animal model in diabetic researches., Highlights • WTC rat was highly resistant to STZ. Insulin secretion by suppling glucose was preserved in WTC rats even after STZ administration. • No significant difference was observed in both GLUT2 and Kir6.2 expression between WTC and Wistar rats. • These results suggest that WTC rat might have powerful antioxidant property to protect bets cells in pancreas..

The objective of this study was to determine the radiocesium transfer rates of pigs fed haylage contaminated with low levels of cesium at different growth stages. We measured the body weight of juvenile and adult pigs during the treatment period to confirm their health status. We also performed pig blood hematologic and biochemical analyses at both growth stages. To our knowledge, this is the first study to report pig radiocesium transfer coefficient rates after 1 month of chronic oral treatment, which is the period assumed to be required for body equilibrium under a diet of radiocesium-contaminated food. The results showed higher radiocesium retention rates in the kidneys, liver, spleen, genitals, psoas major, bladder, thyroid, and urine than in the blood and bone (tibia and femur) of pigs at both growth stages. The radiocesium retention levels were generally higher in juvenile pigs than in adult pigs, with the highest transfer coefficient ratio in the kidneys (16.2%).

Distillation remnants of Shochu, a traditional Japanese liquorare fed to livestock, but their effects on livestock health have not been investigated. Here, we investigated the effects of these remnants on pig stress and pork quality (N = 6/group). The remnants reduced plasma cortisol (17.94 ± 0.92 [control] and 10.59 ± 1.28 [sample]) and increased salivary IgA (6.06 ± 2.21 [control] and 21.60 ± 5.37 [sample]). Blind sensory assessments showed that, in remnant-fed pork, sirloin tenderness (3.18 ± 0.19 [control] and 4.27 ± 0.38 [sample]) and the juiciness, umami, and fat tastiness of fillets were improved. Oleic acid percentages were higher (35.23 ± 0.65 [control] and 37.87 ± 0.60 [sample]) in remnant-fed pork, contributing to a favorable sensory evaluation. Two-group comparisons were analyzed by student's t test. p 0.05. This study promotes the reutilization of remnants to reduce livestock stress and improve meat quality.

Mutations in genes encoding components of the sarcomere cause cardiomyopathy, which is often associated with abnormal Ca2+sensitivity of muscle contraction. We have previously shown that a heart-specific myosin light chain phosphatase small subunit (hHS-M21) increases the Ca2+sensitivity of muscle contraction. The aim of the present study was to investigate the function of hHS-M21in vivo and the causative role of abnormal Ca2+sensitivity in cardiomyopathy. We generated transgenic mice with cardiac-specific overexpression of hHS-M21. We confirmed that hHS-M21increased the Ca2+sensitivity of cardiac muscle contraction in vivo, which was not followed by an increased phosphorylation of myosin light chain 2 isoforms. hHS-M21transgenic mice developed severe systolic dysfunction with myocardial fibrosis and degeneration of cardiomyocytes in association with sinus bradycardia and atrioventricular conduction defect. The contractile dysfunction and cardiac fibrosis were improved by treatment with the Rho kinase inhibitor fasudil. Our findings suggested that the overexpression of hHS-M21results in cardiac dysfunction and conduction disturbance via non-myosin light chain 2 phosphorylation-dependent regulation.NEW & NOTEWORTHY The present study is the first to develop mice with transgenic overexpression of a heart-specific myosin light chain phosphatase small subunit (hHS-M21) and to examine the effects of hHS-M21on cardiac function. Elevation of hHS-M21induced heart failure with myocardial fibrosis and degeneration of cardiomyocytes accompanied by supraventricular arrhythmias.

N-Acetyl-D-mannosamine (ManNAc), a precursor of a sialic acid, is recently reported to improve the cognitive function in aged animals. However, the effect of chronic administration of ManNAc on impaired synaptic transmission and plasticity with age still remain unknown. In this study, we electrophysiologically determined the effect of chronic administration of ManNAc on deteriorated synaptic transmission and plasticity using hippocampal slices from senescence-accelerated mouse prone 8 (SAMP8) which shows age-related impairment of learning and memory. Oral administration of ManNAc for 8 weeks improved the field excitatory postsynaptic potentials (fEPSPs) in both SAMP8 and SAM resistant 1 (SAMR1), the control strain of SAMP8, at 14 months of age, but not at 6 months of age. On the other hand, ManNAc administration improved long-term potentiation (LTP), representative of long-term synaptic plasticity, of 6 month-old SAMP8 but not of age-matched SAMR1. In addition, ManNAc improved LTP of 14 month-old SAMR1 but not of age-matched SAMP8. At the same time, we checked the PPR but ManNAc did not affect the PPRs at either before or after high-frequency stimulation for LTP induction. These results indicate that chronic administration of ManNAc improves the age-dependent attenuation of synaptic transmission and LTP, and shows the availability of ManNAc treatment as potential therapeutic application for cognitive dysfunction.

Aging is associated with a variety of physiological changes originating peripherally and centrally, including within the autonomic nervous system. Sleep-wake disturbances constitute reliable hallmarks of aging in several animal species and humans. Recent studies have been interested in N-acetylmannosamine (ManNAc) a potential therapeutic agent for improving quality of life, as well as preventing age-related cognitive decline. In this study, ManNAc (5.0 mg/ml) was administered in the drinking water of middle-aged male C57BL/6J mice (55 weeks old) for 7 days. Mice were housed under a 12:12 h light:dark cycle at 23-24 °C. We evaluated bio-behavioral activity using electrocardiogram, body temperature and locomotor activity recorded by an implanted telemetry transmitter. To estimate sleep-wake profile, surface electroencephalogram and electromyogram leads connected to a telemetry transmitter were also implanted in mice. Autonomic nervous activity was evaluated using power spectral analysis of heart rate variability. ManNAc-treated mice spent more time in a wakeful state and less time in slow wave sleep during the dark phase. Parasympathetic nervous activity was increased following ManNAc treatment, then the sympatho-vagal balance was shifted predominance of parasympathetic nervous system. Furthermore, improvement in sleep-wake pattern was associated with increased parasympathetic nervous activity. These results suggest that ManNAc treatment can improve bio-behavioral activity and sleep-wake quality in middle-aged mice. This may have implications for improving sleep patterns in elderly humans.

Systemic oxidative stress is considered to cause aging. In this study, to estimate the oxidative stress level in senescence-accelerated mouse prone 8 (SAMP8), we evaluated serum reactive oxygen species production and reduction capacity by measurement of Diacron-Reactive Oxygen Metabolites (d-ROM) and Biological Antioxidant Potential (BAP), respectively, with age. SAMP8 showed earlier increase of d-ROM value with age than SAM resistant 1 (SAMR1), the control strain. The BAP level was the highest in adult SAMP8, whereas SAMR1 presented the sustained BAP values between ages. These results indicate that oxidative stress in SAMP8 is higher than SAMR1. Our study is the first detailed report about d-ROM and BAP in SAMP8 and will provide useful fundamental data for future aging studies.

PKC-potentiated phosphorylation-dependent inhibitory protein of protein phosphatase 1 (CPI-17), an endogenous myosin phosphatase inhibitory protein, is considered a key molecule for Ca2+ sensitization of the contractile apparatus. Here, we have used clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 to generate CPI-17-deficient [knockout (KO)] and threonine 38 (T38)-phospho-resistant mice [threonine mutant into alanine (TA)], and then effects of CPI-17 on vascular contractility in vitro and mean blood pressure (MBP) in vivo were investigated. In isolated thoracic aorta, phorbol 12, 13-dibutyrate induced a sustained contraction of wild-type (WT) mice, whereas no contraction showed from TA or KO mice. A high concentration of KCl solution-induced contraction was not different between transgenic and WT mice. In contrast, phenylephrine (PE)-induced contractions in both mutant strains were significantly smaller than those of WT mice in association with a low level of myosin phosphorylation, suggesting that at least part of PE-induced contraction is regulated by phosphorylation of CPI-17 at T38. Finally, the physiologic role of CPI-17 in the regulation of blood pressure was investigated using radio telemetry. MBP was decreased significantly in both transgenic mice, even with a compensatory increase in heart rate. In summary, we generated KO and constitutively phospho-resistant mouse models of CPI-17 for the first time. p-CPI-17 at T38, possibly by PKC, could be important to maintain vascular contractility and blood pressure in vivo. -Yang, Q., Fujii, W., Kaji, N., Kakuta, S., Kada, K., Kuwahara, M., Tsubone, H., Ozaki, H., Hori, M. The essential role of phospho-T38 CPI-17 in the maintenance of physiological blood pressure using genetically modified mice.

Parameters of heart rate variability would explain changes in heart rate during the disease status in cows and to evaluate whether such changes might provide a more sensitive and quantitative indicator of these conditions than crude indices. For this purpose, we recorded electrocardiograms for 24 hr using a Holter-type electrocardiograph and applied power spectral analysis of heart rate variability in both five clinically healthy and four hospitalized cows. The significant findings of the current investigation were that the diurnal variations of autonomic nervous function are abolished in cows that are sick. This abnormal rhythm was induced by predominant parasympathetic inhibition in these cows. Therefore, the heart rate variability may be a useful indicator of sickness condition in cows.

Cardiac ryanodine receptor gene (RyR2) mutations cause fatal arrhythmogenic diseases such as catecholaminergic polymorphic ventricular tachycardia and arrhythmogenic right ventricular cardiomyopathy. The N-terminal region of RyR2 is one of the hot spots for mutations. In this study, we investigated cardiac phenotypes of a knock-in mouse model carrying R420W mutation of RyR2. The N-terminal R420W mutation has already been found in juvenile sudden death cadavers of unrelated families. The depolarization-induced Ca(2+) transient amplitude was significantly lower in cardiomyocytes from RyR2(R420W/R420W) mice compared with wild-type mice. The time to peak of the Ca(2+) transient was significantly increased in RyR2(R420W/R420W) mice. Furthermore, the prolonged decay time from the peak of the Ca(2+) transient was detected in RyR2(R420W/R420W) mice. ECG telemetry revealed that various types of arrhythmias were induced in RyR2(R420W/R420W) mice in response to administration of caffeine and adrenaline. The mutant mice showed high occurrences of arrhythmias in response to heart stimulants compared with wild-type mice. These findings suggest that R420W mutation impairs depolarization-induced Ca(2+) oscillation in cardiomyocytes, which possibly results in sudden death due to stress-induced arrhythmias.

The microtubule inhibitor colchicine is cardiotoxic and is suggested to impair impulse formation and conduction. However, little is known about the electrocardiographic (ECG) changes induced by colchicine in experimental animals and the detailed pathogenesis of its cardiotoxicity. Therefore, we analyzed cardiotoxicity in colchicine-treated rats using electrocardiographic, histopathological and blood-chemistry approaches. A telemetry device for transmitting ECG data was implanted into male Crl:CD(SD) rats, and ECG tracings were obtained. At 6 weeks of age, 1.25 mg/kg colchicine was injected intravenously once daily for 2 consecutive days, and ECG waveforms and heart rate variability were analyzed. Furthermore, 1.25 mg/kg colchicine or vehicle was injected for 1 or 2 consecutive days in other rats at 6 weeks of age. One day after the final dosing, heart and blood samples were taken for histopathological and bloodchemical examination. ECG analysis revealed a prolonged RR interval, QRS duration, PR interval and QT interval. Heart rate variability analysis showed an increase in high frequency (HF) components as an index of parasympathetic nervous activity. In blood chemical examinations, colchicine induced high levels of parameters of cardiac injury and low levels and/or variations in Ca, inorganic phosphorus, potassium and chloride. Histopathologically, colchicine-treated rats showed eosinophilic granular degeneration and cytoplasmic vacuolation of ventricular myocardial cells but no remarkable change in the atrioventricular node. Not only blood chemical and histopathological changes but also ECG changes were induced in colchicine-treated rats, which indicated a decrease in myocardium excitability and conductivity, and these changes might be related to increased parasympathetic nervous activity and low blood Ca levels.

Aims Dilated cardiomyopathy (DCM) is characterized by ventricular dilation associated with systolic dysfunction, which could be caused by mutations in lamina/C gene ( LMNA ). LMNA -linked DCM is severe in males in both human patients and a knock-in mouse model carrying a homozygous p.H222P mutation ( Lmna H222P/H222P). The aim of this study was to investigate the molecular mechanisms underlying the gender difference of LMNA -linked DCM. Methods and results A whole-exome analysis of a multiplex family with DCM exhibiting the gender difference revealed a DCM-linked LMNA mutation, p.R225X. Immunohistochemical analyses of neonatal rat cardiomyocytes expressing mutant LMNA constructs and heart samples from the LMNA -linked DCM patients and Lmna H222P/H222P mice demonstrated a nuclear accumulation of androgen receptor (AR) and its co-activators, serum response factor, and four-and-a-half LIM protein-2. Role of sex hormones in the gender difference was investigated in vivo using the Lmna H222P/H222P mice, where male and female mice were castrated and ovariectomized, respectively, or treated with testosterone or an antagonist of AR. Examination of the mice by echocardiography, followed by the analyses of histological changes and gene/protein expression profiles in the hearts, confirmed the involvement of testicular hormone in the disease progression and enhanced cardiac remodelling in the Lmna H222P/H222P mice. Conclusion These observations indicated that nuclear accumulation of AR was associated with the gender difference in LMNA -linked DCM.

Post-weaning individual housing induces significant alterations in the social behaviors of laboratory rats. Adult rats use ultrasonic vocalizations as a primary method to communicate social affective states. In this study, we examined the effect of prolonged post-weaning individual housing on the emission of male ultrasonic vocalizations referred to as “50-kHz calls”, which are positively correlated with positive and social affective states in adult male rats. We used an anesthetized sexually receptive female rat to induce 50-kHz calls in adult males. Male subjects that were housed individually emitted fewer 50-kHz calls (both frequency modulated and flat 50-kHz calls) in adulthood compared to subjects housed socially after weaning. Our results showed that prolonged post-weaning individual housing of male rats reduced the male's ability to recognize social and reward cues from female rats and/or to emit sufficient and appropriate 50-kHz calls to female rats. These effects may be associated with developmental dysfunction induced by prolonged post-weaning individual housing.

Post-weaning individual housing induces significant alterations in the reward system of adult male rats presented with sexually receptive female rats. In this study, we examined the effects of post-weaning individual housing on autonomic nervous activity in adult male rats during encounters with sexually receptive female rats to assess whether different affective states depending on post-weaning housing conditions are produced. Changes in heart rate and spectral parameters of heart rate variability indicated that in post-weaning individually housed male rats, both sympathetic and parasympathetic activity increased with no change in the sympathovagal balance, while in post-weaning socially housed male rats, both sympathetic and parasympathetic activity decreased with a predominance of parasympathetic activity. These two patterns of shifts in sympathovagal balances closely resembled changes in autonomic nervous activity with regard to classical appetitive conditioning in male rats. The autonomic changes in male rats housed individually after weaning corresponded to changes associated with the reward-expecting state evoked by the conditioned stimulus, and the autonomic changes observed in male rats housed socially after weaning corresponded to changes associated with the reward-receiving state evoked by the unconditioned stimulus. These results suggest that different affective states were induced in adult male rats during sexual encounters depending on male–male social interactions after weaning. The remarkable change caused by post-weaning individual housing may be ascribed to alteration of the reward system during sexual encounters induced by deficiency of intermale social communication after weaning.

Histopathological and electrocardiographic features of myocardial lesions induced by combretastatin A4 disodium phosphate (CA4DP) were evaluated, and the relation between myocardial lesions and vascular changes and the direct toxic effect of CA4DP on cardiomyocytes were discussed. We induced myocardial lesions by administration of CA4DP to rats and evaluated myocardial damage by histopathologic examination and electrocardiography. We evaluated blood pressure (BP) of CA4DP-treated rats and effects of CA4DP on cellular impedance-based contractility of human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs). The results revealed multifocal myocardial necrosis with a predilection for the interventricular septum and subendocardial regions of the apex of the left ventricular wall, injury of capillaries, morphological change of the ST junction, and QT interval prolongation. The histopathological profile of myocardial lesions suggested that CA4DP induced a lack of myocardial blood flow. CA4DP increased the diastolic BP and showed direct effects on hiPS-CMs. These results suggest that CA4DP induces dysfunction of small arteries and capillaries and has direct toxicity in cardiomyocytes. Therefore, it is thought that CA4DP induced capillary and myocardial injury due to collapse of the microcirculation in the myocardium. Moreover, the direct toxic effect of CA4DP on cardiomyocytes induced myocardial lesions in a coordinated manner.

This study was conducted to clarify and reevaluate the cardiac and autonomic nervous effects of T-2 toxin, which had been previously examined by several acute experiments, in unrestrained and conscious rats implanted with telemetric transmitters. Two groups of rats were given two subcutaneous injections of 0.1 and 0.5 mg/kg of T-2 toxin with an interval of 3 days. Two other groups of rat were pre-implanted with osmotic minipumps by which atropine (20 mg/kg/day) or propranolol (100 mg/kg/day) was continuously administered preceding subcutaneous injection of T-2 toxin (0.5 mg/kg). The present study demonstrated that T-2 toxin caused marked arrhythmias, such as second-degree atrioventricular (AV) block, sinus bradycardia, supraventricular extrasystole, and ventricular extrasystole, which were accompanied by a significant increase in heart rate and a significant decrease in total power and low- and high-frequency power of heart rate variability, during 3 days of observation after the toxin administration. However, the occurrence of arrhythmia with conduction disturbance such as second-degree atrioventricular blocks was markedly diminished by pretreatment with atropine, while the occurrence of ventricular extrasystole was augmented by atropine. The present study with the telemetric measurement elucidated and confirmed that T-2 toxin produced significant cardiac dysfunctions involving disturbance of the conduction pathway influenced by the autonomic nervous activity and also possible direct effects on cardiac myocytes.

Enteritis has been recognized as a major symptom in domestic animals and human patients suffering from feed and food poisonings. The aim of the present study was to clarify the excitatory mechanism of the pelvic nerve afferent which may influence the occurrence of enteritis in response to nociceptive chemical stimuli of the colon in normal and abnormal rats with colitis induced by dextran sulfate sodium (DSS). The pelvic nerve afferent activity was markedly increased by colonic instillation of solution (0.5 ml) of acetic acid (5-25%) and capsaicin (100 μg/ml). The nerve activity was augmented by colonic instillation of capsaicin to a greater extent in rats with DSS-induced colitis than in normal control rats. This augmented activity by capsaicin was more prominent at one day (DSS-1) than at 8 day (DSS-8) after the administration of DSS. The increased nerve activity caused by capsaicin in DSS-1 and DSS-8 was significantly inhibited by pretreatment with ruthenium red, which is a nonselective inhibitor of TRP channels of unmyelinated C-fibers (nociceptors). In conclusion, it was elucidated that the nociceptive function of the pelvic nerve was largely elevated at one day after DSS-induced colitis and such increased function was mostly mediated by TRP channels.

Cholinergic anti-inflammatory pathway (CAP) inhibits unrestrained inflammatory response in a variety of experimental models. Limited research has been done yet to examine the mechanisms of activating CAP on bio-behavioral changes such as heart rate (HR), blood pressure (BP), body temperature (BT), locomotor activity (LA), and autonomic nervous activity (ANA). We observed these parameters using telemetry to clarify pathophysiological mechanisms of CAP. Nicotine significantly attenuated LPS-induced changes in HR, BP, LA, and ANA. These changes were accompanied by significant inhibition of TNF-α and IL-1β syntheses. However the LPS-induced physiological responses persisted much longer than the cytokines production. These results indicate that systemic nicotine treatment inhibits LPS-induced cytokines production and attenuates the associated physiological and behavioral sickness responses.

Delayed rectifier potassium currents such as I (Kr) and I (Ks) play an important role in the repolarization phase of the action potential in cardiac myocytes. Electrophysiological studies have shown that the pig is a useful animal not only for clinical use as a good candidate for humans, but also for basic research in heart function or arrhythmia. However, no studies concerning the potassium channels on a molecular level have been done. To elucidate the expression level and distribution of delayed rectifier potassium channels in pigs, we quantitatively investigated the I (Kr) and I (Ks) channel subunits using the real-time polymerase chain reaction (PCR) method. The hearts from Clawn miniature pigs were separated into the apical and basal regions, and subsequently excised into transmural trisections within each of the left ventricular walls, epicardium, midcardium, and endocardium. After RNA extraction from these sites, real-time PCR was executed with reverse transcriptional products for quantitative analysis. The expression level of KCNE1 was significantly higher than those of KCNQ1, KCNH2, and KCNE2, which were comparable in all sites. Transmural heterogeneity of these potassium channel subunits was not detected on the mRNA level. These results indicate that KCNE1 is a dominant subunit on the post-transcriptional level in the miniature pig.

Background: Connexin-43 (Cx43) expression is reduced or redistributed in heart disease. Restraint or other emotional stressors might cause sudden death in persons with such diseases, but the mechanism of death and its connection to Cx43 during restraint remain unknown. Whether Cx43 distribution or gap junction (GJ) function during restraint is involved in sudden arrhythmic death in rats is addressed in this study. Methods and Results: Male Sprague - Dawley rats underwent immobilization (IMO), and individual electrocardiographic responses were monitored by telemetry. Heart sections were used to examine ventricular Cx43 distribution, and GJ intercellular communication (GJIC) activity was assessed using a dye-transfer assay. IMO induced the translocation of Cx43 into to the GJ-rich fraction, with a peak at 60 min. During IMO, Cx43 immunofluorescence was enhanced at intercalated discs, in association with GJIC activation, and premature ventricular contractions (PVCs) increased. In the presence of the GJ inhibitor, carbenoxolone (0.25 mg·kg-1·h-1), IMO induced lethal ventricular tachycardia or fibrillation in 21.7% of rats, in association with QRS prolongation and increased PVCs. Conclusions: IMO causes Cx43 translocation to intercalated discs, thereby reducing vulnerability to lethal arrhythmias via enhancing GJ coupling. (Circ J 2010; 74: 1087 - 1095)

The purposes of the present study were to clarify whether some Cl − channels exist in rat pleural mesothelial cells, and to investigate functional and molecular characteristics of these channels. Electrophysiological recordings were performed at room temperature using the whole-cell configuration of the patch-clamp technique. We could observe outwardly rectifying Cl − currents in rat pleural mesothelial cells under isotonic conditions. These currents exhibited time-dependent inactivation at potential over + 60 mV and were inhibited by NPPB. It suggests the presence of voltage-dependent Cl − channels. Moreover, we observed the currents activated under hypotonic conditions. Their biophysical and pharmacological properties exhibited as follows; moderate outward rectification of whole-cell currents; time-dependent inactivation at large positive potential; anion selectivity with a type-I Eisenman's permeability sequence (I − > Br − > Cl − > F − > glutamate − ); inhibited by NPPB. These properties are consistent with volume-regulated chloride channels (VRCCs), even though molecular identity of VRCCs could not have been determined, the molecular expressions of mRNA of the Cl − channels ClC-2, ClC-3, pI Cln , MDR1 were confirmed. The properties of VRCCs in the pleural mesothelial cells were consistent with those of ClC-3 channels, and different from those of ClC-2. Therefore, these results suggest that ClC-3 might contribute to the modulation of VRCCs in rat pleural mesothelial cells.

Although the effect of taurine on the heart and liver is well studied, there has been no direct observation concerning the effect of taurine on spatial learning and memory at the behavior level. In this study, we tested the effect of subacute taurine supplementation with evaluation by the Morris water maze method. Although swim distance to find the platform of taurine-supplemented rats was significantly longer than that of control rats due to increase of swimming velocity, escape latency and the efficacy of learning and memory was comparable in both groups. These results suggest that taurine supplemented orally does not affect the learning and memory function.

This study investigated how baro- and chemoreceptor afferents interact with emetic signals from gastric afferents and the vestibular system, and how these interactions modulate emetic and prodromal responses. We performed splanchnic denervation and abdominal vagotomy in anesthetized shrews (Suncus murinus), and then induced emetic responses by gastric distension. Next, we investigated the effects of these gastric afferent sections on cardiovascular and emetic responses induced by electrical stimulation of the aortic depressor nerve (ADN) and the carotid sinus nerve (CSN) with or without gastric distension. Splanchnic denervation abolished the prodromal response before retching and aortic baroreflex inhibition caused by gastric distension, but had no effects on the emetic response. In contrast, abdominal vagotomy abolished the emetic response induced by gastric distension with or without CSN stimulation, but without affecting gastric distension-induced or CSN stimulation-induced vascular and respiratory responses. In conscious animals, CSN denervation significantly suppressed veratrine- and motion-induced emetic responses, whereas ADN denervation had no significant effects. These results suggest that aortic baroreflex inhibition via the activation of splanchnic afferents contributes to the prodromal response before retching and circulatory homeostasis. In contrast, carotid sinus inputs, which are usually non-emetic signals, interact with vagal and vestibular inputs, and modulate the development of retching and vomiting.