Hydroxy-alpha-sanshool activates TRPV1 and TRPA1 in sensory neurons

Sanshools are major active ingredients of Zanthoxylum piperitum and are used as food additives in East Asia. Sanshools cause irritant, tingling and sometimes paresthetic sensations on the tongue. However, the molecular mechanism underlying the pungent or tingling sensation induced by sanshools is not known. Because many transient receptor potential (TRP) channels are responsible for the sensations induced by various spices and food additives, we expressed 17 TRP channels in human embryonic kidney (HEK) cells and investigated their activation by hydroxy-alpha-sanshool (HalphaSS) or hydroxy-beta-sanshool (HbetaSS) isolated from Zanthoxylum piperitum. It was found that HalphaSS, but not HbetaSS, depolarized sensory neurons with concomitant firing of action potentials and evoked inward currents. Among 17 TRP channels expressed in HEK cells, HalphaSS caused Ca(2+) influx in cells transfected with TRPV1 or TRPA1, and evoked robust inward currents in cells transfected with TRPV1 or TRPA1. In primary cultured sensory neurons, HalphaSS induced inward currents and Ca(2+) influx in a capsazepine-dependent manner. Moreover, HalphaSS-induced currents and Ca(2+) influx were greatly diminished in TRPV1(-/-) mice. HalphaSS evoked licking behavior when injected into a single hind paw of wild-type mice, but this was much reduced in TRPV1-deficient mice. These results indicate that TRPV1 and TRPA1 are molecular targets of HalphaSS in sensory neurons. We conclude that the activations of TRPV1 and TRPA1 by HalphaSS explain its unique pungent, tingling sensation.     

Propofol limits rat myocardial ischemia and reperfusion injury with an associated reduction in apoptotic cell death in vivo

Propofol, a rapidly acting, short duration, intravenous hypnotic anesthetic induction agent, is often used in clinical situations where myocardial ischemia/ reperfusion (I/R) injury is a threat. The aim of the present study was to evaluate the protective effect of propofol on myocardial I/R injury in rat due to apoptosis. Myocardial I/R injury were induced by occluding the left anterior descending (LAD) coronary artery for 25 min followed by either 2 h or 6 h reperfusion. Apoptosis was evaluated by Western blot analysis (Bcl-2, Bax expression), DNA strand breaks, TUNEL analysis and measuring myocardial caspase-3 activity. Propofol significantly reduced infarct size and improved I/R-induced myocardial contractile dysfunction by improving left ventricular diastolic pressure and positive and negative maximal values of the first derivative (+dp/dt) of left ventricular pressure. Propofol increased Bcl-2/Bax expression ratio and decreased caspase-3 activity in I/R rat hearts, which resulted in reduction of myocardial apoptosis as evidenced by TUNEL analysis and DNA laddering experiments. In an in vitro study, propofol increased H9c2 cell viability against oxidative stress induced by glucose oxidase (GOX) in a dose-dependent manner. These data suggest propofol limits I/R injury with an associated reduction in apoptotic cell death in vivo.     

Inhibitory effects of 6-(3-hydroxyphenyl)-2-naphthol on tyrosinase activity and melanin synthesis

As a part of an ongoing project searching for new skin-lightening agents, the inhibitory property of 6-(3-Hydroxyphenyl)-2-naphthol (HPN) on melanogenesis was investigated. The inhibitory action of HPN (IC₅₀=15.2 μM) on mushroom tyrosinase was revealed. To further explore the action of HPN on melanogenesis, the inhibition of tyrosinase and melanin levels were measured in B16 melanoma cells (B16 cells). Results show that HPN inhibited tyrosinase activity and reduced melanin in B16 cells. Therefore, our data indicate HPN as a new candidate for depigmentation reagents. Contributed equally to this work.     

Inhibitory effects of 1,3‐thiazine derivatives on melanogenesis

Objectives The aim of this study was to identify a novel skin‐depigmenting agent from synthetic 1,3‐thiazine derivatives. Methods We investigated the inhibitory effects of six kinds of 1,3‐thiazine derivative on melanogenesis by examining their effects on tyrosinase activity and melanin biosynthesis in melan‐a cells and the zebrafish model. Key findings Of the six compounds, 4‐hydroxy‐2,6‐dimethyl‐5,6‐dihydro‐4H‐1,3‐thiazine (TZ‐6) had the strongest anti‐melanogenic effects in cultured melan‐a cells (30.4% inhibition at 100 μM). In addition, TZ‐6 exhibited an inhibitory effect on mushroom and cellular tyrosinase. Based on the results of Western blotting, TZ‐6 reduced the expression of tyrosinase at 100 mM. Additionally, TZ‐6 reduced body pigmentation and inhibited tyrosinase activity in the zebrafish model. Conclusions The results have provided useful information for the development of a skin whitening agent.     

Mollugin induces apoptosis in human Jurkat T cells through endoplasmic reticulum stress-mediated activation of JNK and caspase-12 and subsequent activation of mitochondria-dependent caspase cascade regulated by Bcl-xL

Exposure of Jurkat T cells to mollugin (15–30 μM), purified from the roots of Rubia cordifolia L., caused cytotoxicity and apoptotic DNA fragmentation along with mitochondrial membrane potential disruption, mitochondrial cytochrome c release, phosphorylation of c-Jun N-terminal kinase (JNK), activation of caspase-12, -9, -7, -3, and -8, cleavage of FLIP and Bid, and PARP degradation, without accompanying necrosis. While these mollugin-induced cytotoxicity and apoptotic events including activation of caspase-8 and mitochondria-dependent activation of caspase cascade were completely prevented by overexpression of Bcl-xL, the activation of JNK and caspase-12 was prevented to much lesser extent. Pretreatment of the cells with the pan-caspase inhibitor (z-VAD-fmk), the caspase-9 inhibitor (z-LEHD-fmk), the caspase-3 inhibitor (z-DEVD-fmk) or the caspase-12 inhibitor (z-ATAD-fmk) at the minimal concentration to prevent mollugin-induced apoptosis appeared to completely block the activation of caspase-7 and -8, and PARP degradation, but failed to block the activation of caspase-9 and -3 with allowing a slight enhancement in the level of JNK phosphorylation. Both FADD-positive wild-type Jurkat clone A3 and FADD-deficient Jurkat clone I2.1 exhibited a similar susceptibility to the cytotoxicity of mollugin, excluding involvement of Fas/FasL system in triggering mollugin-induced apoptosis. Normal peripheral T cells were more refractory to the cytotoxicity of mollugin than were Jurkat T cells. These results demonstrated that mollugin-induced cytotoxicity in Jurkat T cells was mainly attributable to apoptosis provoked via endoplasmic reticulum (ER) stress-mediated activation of JNK and caspase-12, and subsequent mitochondria-dependent activation of caspase-9 and -3, leading to activation of caspase-7 and -8, which could be regulated by Bcl-xL.     

The melanocortinergic pathway is rapidly recruited by emotional stress and contributes to stress-induced anorexia and anxiety-like behavior

Neurons producing melanocortin receptor agonist, alpha-MSH derived from proopiomelanocortin, and antagonist, agouti-related protein, are known to be sensitive to metabolic stress such as food deprivation and glucoprivation. However, how these neurons respond to emotional/psychological stress remained to be elucidated. We report here that acute emotional stressors, i.e. restraint and forced swim, evoked mRNA expression of c-fos, a neuronal activation marker, in a high percentage of proopiomelanocortin neurons (up to 53% for restraint stress and 62% for forced swim), with marked variations along the rostro-caudal axis of the arcuate nucleus. In contrast, only a small population of agouti-related protein neurons in this brain region was activated. These neuronal activation patterns were correlated with behavioral reactions. Both stressors suppressed feeding and induced anxiety-like behavior in the elevated plus-maze test, as reflected by a reduction in the percentage of entries and time spent in the open arms. Central pretreatment with SHU9119, a melanocortin receptor antagonist, dose dependently attenuated the anorectic and anxiogenic effects elicited by acute restraint or forced swim. These results indicate that the melancortinergic pathway can be rapidly recruited by acute emotional stress, and that activation of melanocortin signaling is involved in mediating stress-induced anorexia and anxiety.     

Evaluation of hernia repair operation in Child-Turcotte-Pugh class C cirrhosis and refractory ascites

BACKGROUND AND AIM: Abdominal wall hernia is a common feature of decompensated liver cirrhosis and frequently causes life-threatening complications or severe pain. However, there have been no data reported on postoperative mortality, hepatic functional deterioration and recurrence rate according to Child-Turcotte-Pugh (CTP) class and to the presence of refractory ascites. METHODS: The study population comprised 53 liver cirrhosis patients who underwent hernia repair operation. Comparisons were made of 30-day mortality among the different CTP classes, and between those with or without refractory ascites. Liver function was also analyzed just before the operation, in the immediate postoperative period, and in the remote postoperative period. RESULTS: Seventeen patients were in CTP class A, 27 patients in class B, and 9 patients in class C. The median follow-up duration was 24 months. There was single 30-day postoperative mortality in class C, and no CTP class deterioration after 30 days of operation. There was no mortality or recurrences in 17 patients with medically refractory ascites. The difference in 30-day mortality according to CTP class and the presence of refractory ascites did not show statistical significance (P = 0.17 and 0.97, respectively). CONCLUSION: Hernia operation could be done safely in CTP class A and B with low rate of recurrences, and there was no definitive increase in the operative risk in class C. In addition, refractory ascites did not increase operative risk and recurrence rate. Therefore, surgical repair might be recommended even in patients with refractory ascites and poor hepatic function to prevent life-threatening complications or severe pain.     

Relationship between personality disorder symptoms and temperament in the young male general population of South Korea

The aim of the present study was to identify the characteristics of temperament and character in personality disorder symptoms in the young male general population. A total of 585 male subjects from the same community were included in the study (mean age, 19.06 +/- 0.26 years). There was no difference in socioeconomic and educational background. Subjects completed the Personality Disorder Questionnaire-IV+ (PDQ-IV+) and Temperament and Character Inventory (TCI). There were unique correlations between each personality disorder symptom and four temperament profiles. When classification was done through three cluster symptoms by DSM-IV, cluster A symptoms were most strongly associated with low reward dependence (r = -0.46), cluster B with high novelty seeking (r = 0.33), and cluster C with high harm avoidance (r = 0.47). The character dimension, self-directedness was the most powerful predictor of the presence of any personality disorders. In homogenous male general population, unique combinations were found between temperament and each personality disorders. Although the subjects were relatively young and therefore their characters had not yet fully matured, character played an important role in the presence of personality disorder. Temperament can be used to differentiate the personality symptoms and characters used to predict the presence of personality disorder.