A circuit from dorsal hippocampal CA3 to parvafox nucleus mediates social novelty preference deficits induced by chronic social defeat stress / 中国药理学与毒理学杂志

OBJECTIVE The preference for social novelty is crucial to the social life of humans and rodents.However,the neural mechanisms underlying social novelty preference are poorly understood.Dorsal hippocampal CA3(dCA3)is an important brain area that responds to social defeat stress,and the neural circuitry of dCA3→lat-eral septum(LS)participates in the context-associated memory.Meanwhile,the parvafox nucleus(PFN)Foxb1+ neurons regulate the defensive reaction to life-threaten-ing situations.Therefore,we investigate a cell-specific cir-cuit of dCA3CaMKⅡα+→dorsal LSGABA+→PFNFoxb1+ in social novelty preference.METHODS Chronic social defeat stress(CSDS)and three-chamber social interaction test were performed in adult male C57BL/6J mice to detect social behaviors.Optogenetic and chemical-genetic experiments were conducted to regulate the circuit.RESULTS CSDS reduced the preference for social nov-elty in mice and the response of dCA3CaMKⅡα+ neurons dur-ing approach to an unfamiliar mouse was impaired by CSDS.Optogenetic inhibition of dCA3CaMKⅡα+→dLS pro-jection reduced the preference for the unfamiliar mouse versus a familiar mouse.Meanwhile,optogenetic activa-tion of dCA3CaMKⅡα+→dLS projection rescued the prefer-ence for social novelty of CSDS-treated mice.Manipula-tions dLSGABA+→PFN projection activation regulated the preference for social novelty in mice.Optogenetic activa-tion of PFNFoxb1+→lPAG projection reduced the prefer-ence for a familiar C57BL/6J mouse versus a novel object in control mice.CSDS decreased the excitability of dCA3CaMKⅡα+ neurons by up-regulation of Kir2.4(Kcnj14)expression.CONCLUSION Our present study suggest-ed that activation of a cell-specific circuit of dCA3CaMKⅡα+→dLSGABA+→PFNFoxb1+→lPAG reverses the deficits of social novelty preference in defeated mice,and inhibition of this circuit reduces the preference for social novelty.The cir-cuit that regulates the preference for social novelty deficits may provide a new information for the potential therapeu-tic targets for neuropsychiatric diseases.

Xiaoyao San, a Chinese herbal formula, ameliorates depression-like behavior in mice through the AdipoR1/AMPK/ACC pathway in hypothalamus / 中西医结合学报

OBJECTIVE@#Depression and metabolic disorders have overlapping psychosocial and pathophysiological causes. Current research is focused on the possible role of adiponectin in regulating common biological mechanisms. Xiaoyao San (XYS), a classic Chinese medicine compound, has been widely used in the treatment of depression and can alleviate metabolic disorders such as lipid or glucose metabolism disorders. However, the ability of XYS to ameliorate depression-like behavior as well as metabolic dysfunction in mice and the underlying mechanisms are unclear.@*METHODS@#An in vivo animal model of depression was established by chronic social defeat stress (CSDS). XYS and fluoxetine were administered by gavage to the drug intervention group. Depression-like behaviors were analyzed by the social interaction test, open field test, forced swim test, and elevated plus maze test. Glucose levels were measured using the oral glucose tolerance test. The involvement of certain molecules was validated by immunofluorescence, histopathology, and Western blotting. In vitro, hypothalamic primary neurons were exposed to high glucose to induce neuronal damage, and the neuroprotective effect of XYS was evaluated by cell counting kit-8 assay. Immunofluorescence and Western blotting were used to evaluate the influences of XYS on adiponectin receptor 1 (AdipoR1), adenosine 5'-monophosphate-activated protein kinase (AMPK), acetyl-coenzyme A carboxylase (ACC) and other related proteins.@*RESULTS@#XYS ameliorated CSDS-induced depression-like behaviors and glucose tolerance impairment in mice and increased the level of serum adiponectin. XYS also restored Nissl bodies in hypothalamic neurons in mice that exhibited depression-like behaviors and decreased the degree of neuronal morphological damage. In vivo and in vitro studies indicated that XYS increased the expression of AdipoR1 in hypothalamic neurons.@*CONCLUSION@#Adiponectin may be a key regulator linking depression and metabolic disorders; regulation of the hypothalamic AdipoR1/AMPK/ACC pathway plays an important role in treatment of depression by XYS.

Bienestar Subjetivo en contextos de desigualdad y derrota social en jóvenes universitarios de Chile y Ecuador

Resumen Los estudios macroeconómicos evidencian que países con mayor desigualdad social presentan peores indicadores de salud mental y bienestar, sin embargo, otros mecanismos intervinientes no están del todo claro. Recientes investigaciones han propuesto que la percepción de derrota social configura una variable clave para comprender los impactos de las desigualdades. El objetivo de este estudio fue explorar el rol predictor de la derrota social en el bienestar subjetivo de estudiantes universitarios provenientes de países latinoamericanos que exhiben niveles de desigualdad social. Los participantes fueron 347 estudiantes universitarios de Chile y 246 de Ecuador, en los cuales se evaluó la percepción de derrota social, fatalismo, participación social, bienestar social, y bienestar subjetivo. Los resultados del modelo de regresión muestran que la predicción del bienestar subjetivo mejora al incluir las dimensiones de derrota social en el modelo (r2 = .38). Se propone la derrota social como una variable que ayuda a comprender cómo un contexto de desigualdad social puede impactar en el bienestar percibido de jóvenes universitarios.

Abstract Macroeconomic studies show that countries with greater social inequality have worse indicators of mental health and well-being; however, other intervening mechanisms are not entirely clear. Recent research has proposed that the perception of social defeat is a key variable in understanding the impacts of inequalities. The aim of this study was to explore the predictive role of social defeat in the subjective well-being of university students from Latin American countries that exhibit levels of social inequality. The participants were 347 university students from Chile and 246 from Ecuador, in whom the perception of social defeat, fatalism, social participation, social well-being, and subjective well-being were evaluated. The results of the regression model show that the prediction of subjective well-being improves when including the dimensions of social defeat in the model (r2 = .38) Social defeat is proposed as a variable that helps to understand how a context of social inequality can impact the perceived well-being of young university students.

Pathogenesis of chronic social defeat stress model induced depressive-like mouse model according to LC-MS/MS-based metabolomics / 中国药理学与毒理学杂志

OBJECTIVE To explore the pathogenesis of depression according to the LC-MS/MS-based metabolo?mics in the mouse model which exhibits social avoidance state induced by the chronic social defeat stress model (CSDS). METHODS Twenty male C57BL/6N mice were randomly divided into control group and model group suffering CSDS, and the ICR retired breeder mice were used to attack the model group for 14 d of chronic social defeated stress. The open field test and source preference test were both used to observe depression-like behavior. Besides, the social inter?action test is used to observe the social interaction state, especially. After the stress, the serum samples of mice were collected, and the changes of endogenous metabolites were analyzed by LC-MS metabolomics technology, and the pathway analysis of the differential metabolites was performed to explore the pathogenesis of the CSDS induced depres?sive-like mouse model. RESULTS After the stress of CSDS was completed, the mice in the model group showed a significant slowdown in body weight growth, a reduction in the source preference rate, and a significant reduction in the total distance and the number of rearing in the open field test. Distinctively, the social interaction rate is remarkably decreasing. There are 24 differential metabolites found in the serum of CSDS model mice. CONCLUSION The mouse who suffered CSDS stress would show depressive-like behavior. Based on the LC-MS/MS metabolomics, 24 differential metabolites were found in the serum of CSDS model mice. The amino acid metabolism might be significant to the patho?genesis of the CSDS induced depressive-like mouse model.

Cymbopogon citratus aqueous leaf extract attenuates neurobehavioral and biochemical changes induced by social defeat stress in mice / 中草药·英文版

Objective: Psychosocial stress has been implicated in the genesis of psychiatric disorders such as memory deficits, depression, anxiety and addiction. Aqueous leaf extract of Cymbopogon citratus (CYC) otherwise known as lemongrass tea has antidepressant, anxiolytic and anti-amnesic effects in rodents. This study was designed to evaluate if C. citratus could reverse the neurobehavioral and biochemical derangements induced by social defeat stress (SDS) in the resident/intruder paradigm. Methods: Intruder male mice were divided into five groups (n = 7): group 1 received saline (10 mL/kg, p.o.; non-stress control), group 2 also received saline (10 mL/kg, p.o.; SDS control) while groups 3–5 had C. citratus (50, 100 and 200 mg/kg, p.o.) daily for 14 d. The SDS was carried out 30 min after each treatment from day 7 to day 14 by exposing each intruder mouse in groups 2–5 to a 10 min confrontation in the home cage of an aggressive resident counterpart. The neurobehavioral features (spontaneous motor activity-SMA, anxiety, memory, social avoidance and depression were then evaluated. The concentrations of nitrite, malondialdehyde and glutathione as well as acetylcholinesterase activity in the brain tissues were also determined. Results: C. citratus (50, 100 and 200 mg/kg) attenuated hypolocomotion, heightened anxiety, depressive-like symptom, memory deficit and social avoidance induced by SDS. The altered levels of oxidative stress and acetyl-cholinesterase in SDS-mice were positively modulated by C. citratus. Conclusion: The results of this study suggest that C. citratus might mitigate psychosocial stress-induced neurologic diseases in susceptible individuals.

Anxiolytic Effect of Increased NREM Sleep after Acute Social Defeat Stress in Mice / 神经科学通报·英文版

Social defeat stress (SDS) plays a major role in the pathogenesis of psychiatric disorders like anxiety and depression. Sleep is generally considered to involve recovery of the brain from prior experience during wakefulness and is altered after acute SDS. However, the effect of acute SDS on sleep/wake behavior in mice varies between studies. In addition, whether sleep changes in response to stress contribute to anxiety is not well established. Here, we first investigated the effects of acute SDS on sleep/wake states in the active period in mice. Our results showed that total sleep time (time in rapid eye-movement [REM] and non-REM [NREM] sleep) increased in the active period after acute SDS. NREM sleep increased mainly during the first 3 h after SDS, while REM sleep increased at a later time. Then, we demonstrated that the increased NREM sleep had an anxiolytic benefit in acute SDS. Mice deprived of sleep for 1 h or 3 h after acute SDS remained in a highly anxious state, while in mice with ad libitum sleep the anxiety rapidly faded away. Altogether, our findings suggest an anxiolytic effect of NREM sleep, and indicate a potential therapeutic strategy for anxiety.

Effect and mechanism of suberoylanilide hydroxamic acid on fear extinction in mice with chronic so-cial defeat stress / 中华行为医学与脑科学杂志

Objective To investigate the effect and mechanism of suberoylanilide hydroxamic acid (SAHA) on the fear extinction in mice with chronic social defeat stress (SD). Methods Fifty-six male C57BL/6J mice aged 7-8 weeks were randomly divided into control group,social defeat group,control-SAHA group and social defeat-SAHA group to investigate the effect of SAHA and social defeat group,social defeat-AAV BDNF group and social defeat-AAV blank group to investigate the effect of BDNF. Fear extinction in mice was evaluated by fear conditioning test (FC). The levels of BDNF and HDAC2 in mice hippocampus were detected by Western blot (WB). The expression of BDNF-overexpressing virus in hippocampus of mice was detected by immunofluorescence assay. Results (1) Compared with control group,fear extinction in the social defeat group was significantly decreased (P<0. 05). Compared with control group, the level of HDAC2(0. 50±0. 02) in the social defeat group was significantly increased (P<0. 001),while the level of BDNF(0. 16 ± 0. 03) was significantly decreased (P<0. 001) in the social defeat group. ( 2) After using SAHA,fear extinction of mice significantly improved (P<0. 05). Compared with control group,the level of HDAC2 (0. 26±0. 02) in the control-SAHA group was significantly decreased(P<0. 001),and the level of BDNF (0. 40±0. 03) was significantly increased (P<0. 001). Compared with social defeat group,the level of HDAC2 (0. 39±0. 03) in the social defeat-SAHA group was significantly decreased (P<0. 001),and the lev-el of BDNF (0. 28±0. 01) was significantly increased (P<0. 001). (3)After injection BDNF-overexpressing virus,fear extinction was significantly improved(P<0. 05). Conclusion SAHA can enhance fear extinction in mice with chronic social defeat stress and its mechanism may be related to the up-regulation of BDNF ex-pression in hippocampus by inhibiting HDAC2 in hippocampal.

Reliability and validity of defeat scale on anxiety and depression in medical students / 上海交通大学学报（医学版）

Objective: To introduce the defeat scale (DS) and evaluate its reliability and validity among Chinese junior medical students. Methods: With convenience sample method, 665 medical students were examined by the Chinese version of DS, and 29 of them were retested one month later. The structural validity, criterion validity, and content validity of DS were accessed by factor analysis and correlation analysis. The reliability of DS was evaluated by internal consistency reliability (Cronbach's α coefficient), split-half reliability (Spearman-Brown coefficient), and retest reliability. Results: The exploratory factor analysis showed that two factors including decadence (13 items) and low sense of achievement (3 items) could be extracted. Confirmatory factor analysis showed that model revised by two factors fitted well (χ2/df=7.199, RMSEA=0.097, CFI=0.925). The correlation coefficient between each item of content validity and its sub-dimension were among 0.678-0.889. The correlation coefficient was 0.738 between DS and patients' health questionnaire depression scale-9 item, and -0.712 between DS and Rosenberg self-esteem scale. The Cronbach's α coefficient of DS was 0.933, the Spearman-Brown coefficient was 0.925, and the retest reliability was higher than 0.900. Conclusion: The DS has good validity and reliability among Chinese junior medical students.

Investigation of natural depression model under the attack-yield behavior of caged cynomolgus monkeys / 上海交通大学学报（医学版）

Objective • To investigate the natural depression model of Macaca fascicularis induced by submissive-aggressive behaviors. Methods • In a simulated wild environment, two Macaca fascicularis groups (G1 and G2) were respectively established. The two groups consisted of 19 and 14 Macaca fascicularis respectively. The effective frequency of each group's submissive-aggressive behaviors was observed and recorded, the matrix of submissive-aggressive behaviors was analyzed, each individual of the group was calculated separately by David's score(DS), according to the level of individual DS, each group was divided into attack group and yield group; the behavior changes of each individual in 7 periods were recorded by the focus observation and the correlation analysis of 11 different behaviors was carried out. Results • After the formation of these groups, there was fierce conflict between the cynomolgus monkeys. 1 122 and 1 409 submissive-aggressive behaviors were recorded in the two groups respectively. In the submissive-aggressive behavior matrix, the differences between high and low DS in anxiety behavior (t1=-4.053, P1=0.005; t2=-3.041, P2=0.012), conflict behavior (t1=8.478, P1=0.018; t2=7.651, P2=0.002), depression behavior (t1=-3.691, P1=0.006; t2=-2.431, P2=0.045) and exercise behavior (t1=9.639, P1=0.007; t2=3.568; P2=0.002) were statistically significant. Conclusion • The natural depression model of caged Macaca fascicularis is a social defeat model induced by yield-attack behavior.

Sentidos de vitória/derrota para os pais segundo atletas do alto rendimento / Feelings of victory/defeat in parents of high-yield athletes / Sentidos de victoria/derrota para los padres según los atletas de alto rendimiento

Este estudo compreendeu as representações sociais da vitória/derrota para os pais segundo atletas adolescentes do esporte de alto rendimento, na cidade do Recife. A adolescência é compreendida a partir da Psicologia Social histórica, e o embasamento teórico metodológico da Teoria das Representações Sociais abordou os sujeitos em diferentes contextos socioculturais, lugares de pertencimento, experiências, crenças, saberes e sentimentos compartilhados. Adotou-se a perspectiva pluri metodológica com variados recursos de coleta e análise progressiva de dados. Participaram 101 atletas adolescentes do esporte de alto rendimento, nas modalidades natação e vôlei. Os instrumentos utilizados foram questionários de associação livre e entrevistas semi dirigidas. Na análise dos dados, o software EVOC e as técnicas de análise temática de conteúdo de Bardin. Identificamos as representações de vitória para os pais, nas dimensões: pessoal e motivacional, e afetivo emocional e, nas representações sociais da derrota para os pais, além destas, a dimensão técnica. O sentido de vitória para os pais apareceu ampliado: o contexto esportivo, a escolarização, e o crescimento pessoal e profissional na vida. A derrota para os pais é representada como oportunidade de aprendizado e superação para o adolescente, porém, eles mostraram que necessitam do apoio afetivo de sua família para lidar com a auto culpabilização nas situações de fracasso.

This study examined the social representations of victory and defeat held by parents of teenage athletes who participated in a high performance sports in the city of Recife. The developmental stage of adolescence is understood based on sociohistorical psychology, while the social representations theory constituted the frame of reference for approaching individuals from different social-cultural contexts, places, experiences, beliefs, knowledge, and shared feelings. A multi-methodological orientation was employed with a wide range of resources for the collection and progressive analysis of data. In this study, participants involved 101 teenager athletes, who participated in a high performance sport, either swimming or volleyball. The tools utilized included a free association questionnaire and semi-structured interviews. EVOC 2000 and Bardin's thematic content analysis were used for data analysis. Representations of victory were identified from the parents for the following dimensions: personal and motivational and affective–emotional. In addition to those two dimensions, the technical dimension was also identified for the parental representation of defeat. The victory meaning for parents was not restricted just to the sport area, it was extended to other contexts such as education level, professional and personal growth. The value of defeat for parents was represented as an opportunity for learning and overcoming situations to the teenage athlete. However, they also showed the need for affective support from their families to deal with self-blame in the event of failure.

Este estudio comprendió las representaciones sociales de la victoria/derrota para los padres según adolescentes atletas de deporte de alto rendimiento en la ciudad de Recife. La Adolescencia comprendida a partir de la Psicología Socio Histórica y la base teórico- metodológica de la Teoría de las Representaciones Sociales abordó los sujetos en diferentes contextos socioculturales, lugares de origen, experiencias, creencias, saberes y sentimientos compartidos. Se adoptó una perspectiva plurimetodológica con variados recursos de recolección de análisis progresivo de datos. Participaron 101 atletas adolescentes de deporte de alto rendimiento en las modalidades de natación y volibol. Los instrumentos utilizados fueron cuestionarios de asociación libre y entrevistas semi-dirigidas. En el análisis de los datos, se usó el software EVOC y las técnicas de análisis temático del contenido de Bardin. Identificamos las representaciones de victoria para los padres en las dimensiones: personal-motivacional y afectivo-emocional y, en las representaciones sociales de la derrota para los padres, además de éstas, se consideró la dimensión técnica. El sentido de victoria para los padres apareció ampliado: el contexto deportivo, la escolarización y el crecimiento personal y profesional en la vida. La derrota para los padres es representada como oportunidad de aprendizaje y superación para el atleta adolescente, sin embargo, ellos demostraron que necesitan apoyo afectivo de su familia para lidiar con la auto culpabilidad en las situaciones de fracaso.

Endomorphin peptides: pharmacological and functional implications of these opioid peptides in the brain of mammals. Part two / Las endorfinas: implicaciones farmacológicas y funcionales de estos péptidos opioides en el cerebro de los mamíferos. Segunda parte

Endomorphin-1 (EM1) and Endomorphin-2 (EM2) represent the two endogenous C-terminal amide tetrapeptides shown to display a high binding affinity and selectivity for the µ-opioid receptor as reported previously (see previous paper, Part I). Endomorphins injected into the VTA were shown to enhance the development of behavioral sensitization responses to amphetamine (AMPH), besides of inducing an increase of locomotion (horizontal) activity in animals. These studies showed that EM2 was significantly more potent than EM1 in modulating the increased opioid-mediated ambulatory responses by altering the dopamine (DA) projecting system in the globus pallidus in tested animals. Several transmission systems (e.g., GABA) have been shown to participate in the endormorphin-induced locomotor responses. EM1 injected into the VTA produced potent rewarding effects in rodents, similar to the rewarding responses produced by distinct opiate compounds. The opioid rewarding responses induced by EM1-2 were shown to be mediated via the activation of both GABAergic and the dopamine (VTA-NAc-PFCx) transmission systems in the brain. Moreover, EM1-2 peptides injected into the VTA, but not in the NAc, produced similar related-rewarding responses induced by low doses of morphine. However, ICV administration of EM1 was shown to enhance a significant conditioned-place preference (CPP); whereas EM2 displayed a place aversion in tested animals. With regard to stress-related behaviors and physiological responses in mammals, endomorphin peptides have been proposed to modulate the HPA axis function via activation of the NTS-projecting neural system impinging on hypothalamic neurons, and/or via activation of the PAG (ventrolateral area) mediating analgesic responses-induced by stress. EM1-2 peptides have been shown to induce mood-related behaviors. For instance, administration of EM1 induced an increased anxiolytic response in mice when tested in elevated plus maze paradigms, results that showed that the µ-opioid receptor modulates mood-related responses in animals and humans, as well. Interesting enough is the recent observation that EM1-2 peptides may induce antidepressant-like behaviors in animals models of stress and depression, whereby EM1-2 peptides have been shown to up-regulate in a dose-dependent manner the neuronal expression of the BDNF mRNA in rat limbic areas involved in stress and depressive-like behaviors. Thus, these studies led to the proposition that endomorphin peptides may play crucial roles in psychiatric disorders (e.g., depression, schizophrenia). Furthermore, over the past years, it has been shown that µ-opioid receptor agonists (e.g., morphine, DAMGO; morphine-6β-glucuronide) displayed potent orexigenic activities in the CNS of mammals, similar to that displayed by EM1-2 peptides, whose dose-dependent orexigenic activity appears to be mediated by the endogenous opioid peptide, Dynorphin A, acting on its cognate κ-opioid receptor at the hypothalamus. Extensive studies revealed the activity of the EOS (e.g., β-endorphin) on the regulation of gonadal hormones and sexually-induced behaviors (e.g., lordosis) in female rats. β-endorphin or morphiceptin have been shown to facilitate lordosis behaviors in estrogen- and/or estrogen/progesterone primed rats, whereas EM1-2 peptides injected into third ventricle or into the diagonal band (DB) produced dose- and time-dependent, naloxone-reversible lordosis responses in female rats. These results posit that EM1-2 peptides produce their sexual behaviors and mating responses via modulating the cell release of LHRH and modulating GABA transmission system in the brain. Endomorphins have been shown to impair short- and long-term memory processing in mice when exposed to different learning paradigms. These opioid mediated effects appear to be regulated through the interaction of both cholinergic and dopaminergic transmissions in the brain. In addition, endomorphins have been shown to modulate cardiovascular and respiratory bioactivities, acting on several rostrocaudal areas of the CNS of mammals. Administration of EM1-2 peptides induced a significant reduction of heart rate and blood pressure in normotensive and hypertensive rats, via regulation of GABA and glutamate transmission systems. Although the exact endogenous mechanisms by which EM1-2 peptides produce their vasoactive responses are still unclear, several studies suggested that the peptide activity depends on the synthesis and release of nitric oxide (NO) from endothelial cells enhanced by activation of µ-opioid receptors. Studies on respiratory function showed that EM1-2 peptides attenuate and produce significant respiratory depression in tested animals. Finally, EM1-2 peptides have been shown to induce important inhibitory gastrointestinal effects via the activation of µ-opioid receptors localized in myenteric-plexus neurons that innervate smooth-muscle cells producing a dose-dependent- and CTOP-reversible inhibition of electrically-induced twitch ileum contractions, probably mediated through a reduced release response of several peptide and non-peptide transmitters.

La endomorfina-1 (EM1) y la endomorfina-2 (EM2) son dos péptidos bioactivos que poseen la más alta afinidad de unión selectiva por el receptor opioide µ en comparación con la unión de distintos ligandos agonistas a este subtipo de receptor opioide (véase resumen y texto del capítulo anterior, parte I). Estudios farmacológicos y conductuales han demostrado que la inyección de las EM1-2 en el área ventrotegmental (AVT) genera respuestas conductuales de sensibilización locomotora a la anfetamina (AMPH), además de incrementar la actividad locomotora de tipo horizontal en los roedores tratados. Estos estudios mostraron que la EM2 fue significativamente más potente que la EM1 en inducir las respuestas locomotoras detectadas, mediadas a través de la alteración de la actividad sináptica de dopamina (DA) y en el globus pallidus de los animales tratados. Asimismo, estudios fármaco-conductuales similares demostraron que otros sistemas de transmisión participan conjuntamente con el sistema dopaminérgico en la generación de los efectos locomotores inducidos por las EM1-2, como es el caso del sistema gabaérgico (GABA). Más aún, la inyección de EM1 en la región AVT del cerebro de roedores mostró generar respuestas potentes de recompensa placentera, similares a las reportadas por distintos alcaloides opiáceos de alto potencial adictivo, posterior a su administración sistémica. Más aún, la inyección de endomorfinas en la región AVT del cerebro del roedor, mas no en el núcleo accumbens (NAc), mostró generar respuestas de recompensa paralela a la generada posteriormente a la administración de dosis bajas de morfina. En línea con los efectos farmacológicos inducidos por las EM1-2, estudios fármaco-conductuales demostraron que la administración ICV de la EM1 fue capaz de generar respuestas de preferencia de lugar en roedores tratados CPP, por sus siglas en inglés, conditioned place preference, en tanto que la administración de EM2 generó respuestas opuestas, esto es, respuestas de aversión al lugar. Estudios conductuales relacionados con el fenómeno de estrés mostraron que las EM1-2 son capaces de modular la actividad funcional del eje HHA (eje hipotálamo/hipófisis/glándula adrenal) a través de la activación del sistema de proyección neuronal del tracto solitario (NTS, por sus siglas en inglés), al hipotálamo y/o a través de la activación del área ventrolateral de la sustancia gris periacueductal (PAG, por sus siglas en inglés); componente importante del sistema opioide endógeno, que median respuestas analgésicas (antinociceptivas) inducidas por estímulos estresantes. Asimismo, la administración de endomorfinas (v.g., EM1) mostró generar incrementos de conductas de naturaleza ansiolítica en ratones expuestos a paradigmas experimentales de generación de conductas estresantes (v.g., laberinto elevado). Estos estudios sugieren que la generación de conductas de estrés-emocional inducidas por las endomorfinas es mediada a través de la activación del receptor opioide µ en neuronas del hipotálamo responsables de regular la secreción de factores liberadores de distintas hormonas hipofisiarias (v.g., CRH, LHRH). Más aún, resulta interesante que las endomorfinas sean capaces de inducir conductas antidepresivas o de tipo antidepresivos como se ha reportado recientemente en modelos animales de estrés y depresión. Estos estudios mostraron que las respuestas conductuales de reacción al estrés y las conductas antidepresivas mediadas por las EM1-2 están ligadas con la expresión neuronal del mensajero de RNA que codifica para el factor trófico (BDNF, por sus siglas en inglés, brain derived neurotrophic factor), en áreas del sistema limbico, y que es inducida en forma dosis-dependiente por las endomorfinas, posterior a su administración ICV. Por lo tanto, estos estudios han permitido proponer que las endomorfinas cumplen un papel relevante durante el curso o desarrollo de las enfermedades mentales (v.g., esquizofrenia y depresión). En extensión a estos estudios conductuales, estudios recientes han demostrado la actividad orexigénica de las endomorfinas en forma similar a lo previamente detectado con distintos ligandos agonistas del receptor opioide µ (v.g., morfina, DAMGO; morfina-6β-glucurónido). Si bien estos estudios mostraron que tanto las EM1-2 como diversos agonistas del receptor opioide µ exhiben potentes actividades orexigénicas en el SNC de roedores, la actividad de las EM1-2 parece depender de la actividad de la dinorfina A y su unión sobre su receptor opioide K en neuronas hipotalámicas. Más aún, diversos estudios han mostrado que el sistema opioide endógeno (a través de la β-endorfina) regula conductas de naturaleza sexual y apareamiento (v.g., lordosis), además de modular la secreción y/o actividad de hormonas de origen gonadal (estrógenos, progesterona). Estudios similares en roedores hembras mostraron que la microinyección de EM1-2 en áreas específicas del sistema límbico y/ o la administración IT de ambos péptidos era capaz de generar respuestas sexuales de apareamiento, similares a las detectadas por la p-endorfina y morficeptina en la misma especie de animal, siendo bloqueados los efectos por la administración de naloxona. Estas respuestas conductuales inducidas por las EM1-2 mostraron estar ligadas a la liberación neuronal de LHRH, como de la activación y modulación del sistema de transmisión gabaérgico. En cuanto a las funciones de memoria y aprendizaje, diferentes estudios han demostrado que la administración ICV de EM1-2 en ratones expuestos a diferentes paradigmas de aprendizaje experimental, los péptidos opioides alteran significativamente los mecanismos de procesamiento y consolidación de memoria a corto y largo plazo en los animales tratados. Estos efectos parecen depender de la modulación del sistema opioide (v.g., el receptor opioide µ) sobre los sistemas de transmisión colinérgica y dopaminérgica en el cerebro de los mamíferos. Asímismo, diversos estudios han demostrado que tanto las EM1-2 como los alcaloides opiáceos y opioides endógenos modulan funciones cardiovasculares y respiratorias. En este contexto, diversos estudios mostraron que la administración de EM1-2 en ratas normotensas e hipertensas produce cambios fisiológicos significativos en la presión sanguínea y la frecuencia cardiaca. Si bien no están del todo esclarecidos los mecanismos por los cuales las endomorfinas producen sus respuestas cardiovasculares, diversos estudios sugieren que la actividad de estos péptidos está en función de la actividad e interacción de los sistemas de transmisión gabaérgico y glutamatérgico, respectivamente. Más aún, otros estudios sugieren que las respuestas fisiológicas de estos péptidos dependen de la actividad del óxido nitroso (NO, por sus siglas en inglés) liberado de los vasos sanguíneos, en respuesta de la activación del receptor opioide µ. Finalmente, diversos estudios han mostrado que las EM1-2 y la activación del receptor opioide µ producen efectos inhibitorios sobre la contracción del músculo liso del tracto gastrointestinal, generados a través de una reducción sostenida en la liberación de neurotransmisores de terminales sinápticas del plexo mientérico, mismas que inervan el tejido muscular liso del tracto gastrointestinal.

Bone formation e ffe ct o f HA/beta-TCP composite powders in rabbit calvarial bone defects: Histologic study / 대한치주과학회지

The purpose of the present study was to evaluate the histologic results of bone cavities that were surgically created in the calvaria of rabbit and filled with HA/beta-TCP composite powders, which had been developed in Korea (Dentium, Korea). Ten young adult rabbits were used. Four defects were surgically produced in calvaria of each rabbit. Each rabbit was anesthetized with Ketamine-HCl (5 mg/kg, Yuhan Cor. Korea) and Xylazine-HCl (1.5 ml/kg, Yuhan Cor. Korea)). An incision was made to the bony cranium and the periosteum was reflected. Using a trephine bur (external diameter: 8 mm, 3i, USA), 4 'through-and-through' bone defects were created with copious irrigation, and classified into 4 groups: control group: no graft materials, experimental group I: normal saline + graft materials: experimental group II: venous blood + graft materials: experimental group III: graft materials only. The defects were randomly filled with graft materials. The defects were closed with resorbable suture material. At the end of the surgical procedure, all animals received a single intramuscular injection of antibiotics Gentamicin (0.1 mg/kg, Dae Sung Microb. Korea). Rabbits were sacrificed with phentobarbital (100 mg/kg) intravenously at 1-, 2-, 4-, 6- and 8-week after. Specimens were treated with hydrochloric acid decalcifying solution (Fisher Scientific, Tustin, CA) and sectioned by bisecting the 8 mm diameter defects. The histologic specimens were prepared in the general method with H & E staining at 6 micrometer in thickness. The results were as follows; 1. New bone formation showed from after 2-week of surgery in defect area. As time lapsed, lots of new bone formation and mature bones showed. 2. Histologically, degree of new bone formation could not be discerned among the experimental groups. But, for experimental group II, lots of cells gathered around graft materials after 1-week of surgery, new bone formed slightly faster and than the others at 1-week after. For experimental group I, a few inflammatory finding showed around graft material at after 1-week and after 2-week of surgery. 3. No bone formation did show for control group. Based on histologic results, the new HA/beta-TCP composite powders appeared to act as a scaffolding material for regeneration of osseous defects.