Effect of low frequency electrical stimulation on hormone levels in the organs of Chinese tree shrew cadavers / 中国实验动物学报

Objective To study the effect of low frequency electrical stimulation on hormone levels in organs of Chinese tree shrews after death.Methods Giving Chinese tree shrews low frequency electrical stimulation.At 0 h, 3 h, 6 h, 12 h, 18 h, 24 h, 36 h and 72 h after death, the thyroid, liver, spleen were taken,and the levels of endothelin (ET), atrial natriuretic factor( ANF) , thromboxane ( TX) were determined by RIA method.At 0 h after death, midbrain ventral tegmental area ( VTA) of Chinese tree shrews was taken to detect the c-fos expression.Results After electrical stimula-tion, ET, ANF, TX levels in the cadaver organs and VTA c-fos expression of Chinese tree shrews were significantly in-creased than in the control group.The contents were decreasing with the time after death.Conclusions Low frequency e-lectrical stimulation can induce the synthesis and release of hormones in organs and c-fos expression in brain tissue of Chi-nese tree shrews.

A single high dose of chlorpyrifos reduces long-term basal c-fos expression in the rat arcuate hypothalamic nucleus / La administración de una dosis aguda de clorpirifós reduce a largo plazo la expresión basal de c-fos en el núcleo arqueado del hipotálamo

Chlorpyrifos (CPF) is an organophosphate compound used worldwide as a pesticide in agriculture that, after subcutaneous injection, keeps acetylcholinesterase (AChE) activity inhibited within an organism for months. Ample clinical and experimental evidence shows that CPF exposure induces relevant and persistent neurobehavioral deficits in humans and animals, even after one single episode/injection. Additionally, clinical and epidemiological studies evidence that a significant percentage (60%) of Gulf War veterans as well as agricultural workers suffering from acute OP intoxication may have developed intolerance to nicotine and ethanol-containing beverages. Consistent with it, administration of a single high dose of CPF to adult Wistar rats elicited long-lasting reduced voluntary ethanol drinking and increased sedation to ethanol without evidence of altered ethanol metabolism, which indicates that CPF-ethanol neurobiological interactions may exist. In this study, we explore whether CPF exposure induces significant disturbances in basal and/or ethanol-evoked neural activity in a set of cholinoceptive brain regions critically involved with neurobiological responses to ethanol. For this aim, brain regional c-fos expression in response to acute ethanol (1.5 or 3.0 g/kg, i.p.) or saline was assessed in adult male Wistar rats previously injected with either a single high dose of CPF (250 mg/kg, sc) or vehicle. We found that CPF administration reduces long-term basal, but not ethanol-evoked, c-fos expression in the arcuate hypothalamic nucleus. Because independent brain pathways may modulate acute responses to ethanol and voluntary ethanol consumption, we do not rule out the contribution of basal neural disturbances observed in the Arc to CPF-elicited ethanol avoidance.

El clorpirifós (CPF) es un compuesto organofosforado utilizado como plaguicida en todo el mundo. Después de ser inyectado de manera subcutánea, mantiene la actividad de la enzima acetilcolinesterasa (AChE) inhibida durante meses. Estudios clínicos y experimentales muestran que la exposición al CPF induce déficits neuroconductuales persistentes en seres humanos y animales, incluso después de un solo episodio/inyección. Además, estudios epidemiológicos evidencian que un porcentaje significativo (60%) de los veteranos de la Guerra del Golfo, así como los agricultores que sufren una intoxicación aguda por organofosforados, desarrollan intolerancia a la nicotina y las bebidas que contienen etanol. Datos experimentales mostraron que la administración de una sola dosis alta de CPF en ratas Wistar adultas provoca una reducción a largo plazo del consumo voluntario de etanol y un incremento en la sedación provocada por etanol sin evidencias de alteración del metabolismo de esta sustancia, lo que indica que pueden existir interacciones neurobiológicas entre CPF-etanol. En este estudio, se explora si la exposición a CPF induce alteraciones significativas en la actividad neuronal basal o evocada por el etanol en un conjunto de regiones colinoceptivas del cerebro involucradas en las respuestas neurobiológicas al etanol. Para ello, se evaluó la expresión de c-fos en respuesta a una dosis de etanol aguda (1.5 o 3.0 g/kg, ip) o solución salina en ratas Wistar macho adultas previamente inyectados con dosis aguda de CPF (250 mg/kg, sc) o un vehículo. Encontramos que la administración de CPF redujo la expresión basal de c-fos a largo plazo, pero no la evocada por el etanol en el núcleo arqueado del hipotalámo. Debido a que vías cerebrales independientes podrían modular las respuestas agudas al etanol y el consumo voluntario del mismo, no se descarta la contribución de las alteraciones neuronales basales observadas en el Arc en la evitación del consumo de etanol provocado por CPF.

Effects of NSAIDs on Fos expression in conscious rat model of vasculogenic headache / 中国实验动物学报

Objective To define the functional mechanisms of two NSAIDs , paracetamol and ibuprofen , in specif-ic brain regions in headache control by observing the distribution of Fos -immunoreactive neurons in trigeminal ganglia and trigeminal nucleus caudalis in conscious rat models of vasculogenic headache .Methods Thirty male Sprague-Dawley rats were randomly divided into three groups: control group ( saline group ) , acetaminophen group and ibuprofen group .Each rat was given electrical stimulation ( frequency 20 Hz, current 3-5 mA, pulse width 0.25 ms) at 50 minutes after injec-tion .The rats were killed and perfusion fixed after electrical stimulation .Trigeminal ganglia and trigeminal nucleus caudalis of the brains were taken out for paraffin sections and immunohistochemical staining , and Fos-immunoreactive neurons were counted under the Image J system .Results After electrical stimulation , there were significant differences of Fos protein expression in bilateral trigeminal ganglia and spinal trigeminal nucleus caudalis between the saline group and groups of non -steroidal anti-inflammatory drugs , but no significant difference of Fos protein expression in bilateral trigeminal ganglia and spinal trigeminal nucleus caudalis between the acetaminophen group and ibuprofen group .Conclusions The changes of Fos expression in bilateral trigeminal ganglia and spinal trigeminal nucleus caudalis after treatment with NSAIDs suggest that such structures participate in the pain transmission and expression and the pharmacology course of analgesic drugs .

Hormonal and cognitive factors associated with the exploratory behavior of rats submitted to repeated sessions of the elevated plus-maze

Naive rats submitted to the elevated plus-maze (EPM) display a characteristic increase in open arm exploration and reduced risk assessment behaviors (RABs) after the administration of anxiolytic drugs. Upon re-exposure to the maze, however, the traditional measures of the EPM become resistant to these drugs. This intriguing phenomenon was initially observed for the benzodiazepine chlordiazepoxide and referred as one-trial tolerance (OTT). In this review, we summarized hormonal, cognitive and neuroanatomical data obtained from rats submitted to the test/retest protocol in the EPM. The re-exposure to the EPM is characterized by more prominent RABs and a distinct Fos protein distribution in the brain, particularly in limbic structures involved with the cognitive aspects of fear, such as the ventral regions of the medial prefrontal cortex (mPFC) and amygdala. Interestingly, naive rats treated with midazolam had a significant decrease in the number of Fos-positive neurons in the anterior cingulate cortex, area 1 (Cg1), anterior and dorsal premammillary nuclei of hypothalamus. On the other hand, midazolam caused a significant decrease in the number of Fos-positive neurons in the mPFC, amygdala, dorsomedial nucleus of hypothalamus and raphe nuclei in maze-experienced rats. Cg1 was the only structure targeted by the benzodiazepine in both sessions. Systemically administered midazolam before test or retest sessions reduced the RABs and plasma corticosterone levels in rats submitted to both sessions. Similar behavioral results were obtained with intra-Cg1 infusions of midazolam. The results reviewed here support the view of the crucial role of the RABs in the development of the OTT and point to this mPFC area as an important locus for the anxiolytic-like action of benzodiazepines in rodents.

The effects of adenosine on the discharging electricities and the c-fos expression of neurons in habenula nucleus of rats / 中国免疫学杂志

Objective:To investigate the effect of adenosine (Ado) on the unit discharging electricities in habenula nucleus and on the c-fos expression in lateral habenular complex,and the influence of adenosine on the neuron activities and related gene expression involved in affecting sleep in habenula nucleus and the possible mechanisms.Methods:Intraperitoneal injection,brain flakes pouring of rats,immunohistochemistry and other methods were useel.Results:Ado pouring into flakes of brain depressed the unit discharging electricities of neurons in medial habenular complex(MHb),but obviously increased that of lateral habenular complex(LHb).0.5 h after the six rats being injected intraperitoneally with Ado,the c-fos protein expression in lateral habenular nucleus was significantly increased compared to the group with saline injection.Conclusion:Ado may restrain the unit discharging electricities of neurons in medial habenular complex but excite those in lateral habenular complex.At the meantime,Ado may increase the c-fos expression in LHb.This provides the experimental evidence that Ado may improve the sleep quality.

The Cross Effects of Needle Electrical Stimulation according to Electrode Placements on the Analgesia in Arthritic Rat Model

OBJECTIVE: To investigate the analgesic effect of needle electrical stimulation (NES) according to the electrode placement in acute arthritic rat model. METHOD: Male Sprague-Dawley rats (120 rats, 250+/-50 g) were injected with a mixture of 3% carrageenan and 3% kaolin into the right knee joint. Rats were randomly assigned into one of four groups: Group I, control group (n=30); Group II, arthritic limb-induced control group (n=30); Group III, NES application group on the ipsilateral arthritic limb (n=30); Group IV, NES application group on the contralateral arthritic limb (n=30). We applied the NES (2 Hz, 200micro s, 20 min) to group III and IV. We assessedthe change of paw withdrawal latency (PWL) and the immunoreactivity of c-fos by immunohistochemistry at baseline, 4, 8, 12 and 24 hours after induction of arthritis. RESULTS: NES was more effective in Group III and IV than group II 8 hours after the induction of arthritis (p < 0.001) based on the results of PWLs and c-fos immunoreactivity. The analgesic effects of Group III were greater than those of group IV (p < 0.001). CONCLUSION: Contralateral NES on arthritic limb reduced pain in arthritic rat model as effectively as ipsilateral NES.

Effects of Naloxone on Morphine Analgesia and Spinal c-fos Expression in Rat Formalin Test / 대한통증학회지

BACKGROUND: This study was performed to evaluate the dose-related effects of naloxone on morphine analgesia in the rat formalin test, and observe the correlation of pain behavior and spinal c-fos expression induced by a formalin injection. METHODS: Fifty rats were divided into five groups; control, morphine (morphine pre-treated, intra-peritoneal injection of 0.1 mg of morphine 5 min prior to formalin injection), and three naloxone groups, which were divided according to the administered dose-ratio of naloxone to morphine; 20: 1 (5microgram), 10: 1 (10microgram), and 1: 1 (100microgram) representing the low-, medium-, and high-dose naloxone groups, respectively, were injected intra-peritoneally 16 min after a formalin. A fifty ul of 5% formalin was injected into the right hind paw. All rats were observed for their pain behavior according to the number of flinches during phases 1 (2-3, 5-6 min) and 2 (1 min per every 5 min from 10 to 61 min). The spinal c-fos expression was quantitatively analyzed at 1 and 2 hours after the formalin injection using a real-time PCR. RESULTS: The morphine pre-treated (morphine and three naloxone) groups during phase 1, and the morphine, low- and medium-dose naloxone groups during phase 2, showed significantly less flinches compared to those of the control (P < 0.05). In the three naloxone groups, the numbers of flinches were transiently reduced following the naloxone injection in the low- and medium-dose groups compared to those of the morphine group (P < 0.05). The duration of the reduced flinches was longer in the medium-dose group (P < 0.05). The high-dose group revealed immediate increases in flinches immediately after the naloxone injection compared to those of the morphine, low- and medium-dose groups (P < 0.05 for each). The spinal c-fos expression showed no significant patterns between the experimental groups. CONCLUSIONS: Our data suggest that relatively low-dose naloxone (1/20 to 1/10 dose-ratio of morphine) transiently potentiates morphine analgesia; whereas, high-dose (equal dose-ratio of morphine) reverses the analgesia, and the spinal c-fos expression does not always correlate with pain behavior in the rat formalin test.

Comparison of Wound Healing and Inflammation Depending on the ablation Methods in Rabbits

In excimer laser ablation, the methods of epithelial removal include mechanical, chemical(alcohol), and laser ablation. To investigate the effects of the de-epithelialization methods, we removed corneal epithelia of 60 rabbits with above three methods and examined corneal epithelial healing time, stromal PMN cells, and immunohistochemical expression of c-fos with time interval. Corneal epithelia healed in 48 hours in the alcohol and laser ablation groups, but in 72 hours in the mechanical ablation group. The count of the stromal PMN cells was maximal in 12 hours in all three groups, and the inflammaion was prolonged in the alcohol ablation group(p<0.05). The c-fos was expressed after 6 hours, 12 hours and 24 hours in all 3 groups and after 48 hours only in the mechanical ablation group. This study suggests that mechanical ablation may produce a larger damage to cornea than laser and chemical ablations and the expression of c-fos in corneal epithelium may be significant findings related to epithelial wound healing.

c-Fos expression in the rat trigeminal sensory nucleus complex following tooth movement / 대한치과교정학회지

The c-fos is known as neuronal marker of second neurons which is activated by noxious peripheral stimulation. To investigate the changes of c-fos expression in the trigeminal n icleus complex during tooth movement, immunohistochemical study was performed. Experimental rats(9 weeks old, 210 gm, 21 rats) were divided into seven groups( normal, i hour group, 3 hour group, 6 hour group, 12 hour group, 1 day group, 3 day group). Rats in the normal group were anesthesized without orthodontic force. Rats in the experimental groups were applied orthodontic force (approximately 30 gm) to upper right maxillary molar. Frozen sections of brain stem were immunostained using rabbit antisera. The changes of c-fos expression were observed with respect to rostrocaudal distribution, laminar organization, and duration of orthodontic force application. The study results were as follows. · The c-fos nuclei in the dorsal part were observed from ipsilateral transition zone of subnucleus interpolaris and subnucleus caudalis to Ci cervical dorsal horn rostrocaudally. The maximal peak point was the rostral part of subnucleus caudalis. The greatest proportion of c-fos cells were located within lamina I and II. · The c-fos nuclei in the dorsal part were observed from the most caudal part of subnucleus interpolaris to the middle part of the subnucleus caudalis. · The number of c-fos imniunoreactive dot increased at 1 hour group, reached its maximum at the 3 and 6 hour groups, and showed a decreasing trend after 12 hours. These results imply that nociceptive stimulation caused by continuous orthodontic force might be modulated by transition zone of subnucleus interpolaris and subnucleus caudalis, subnucleus caudalis, C1 spinal dorsal horn.

High Activities of Protein Kinases C and M in Fresh Human Stomach and Breast Tumors

The activities of Ca+2-PL dependent protein Kinase (PKC) and independent protein kinase(RKM) were measured in human stomach and breast tumors and in the respective counterparts of normal tissue. Expression of c-fos and c-myc of the tissues were also measured. RNAs of c-fos and c-myc were unexpectedly high in the tissue from normal stomach and breast as well as in all cancer tissue. On the other hand, cytosolic and particulate PKC activities were higher in the tumors as compared to those of normal controls. Notably, some cases exhibited. altered activities of PKC i.e. increased RKM activities as high as RKC, which might be related to the autocrine control of growth in the tumor mass.

Effect of spinal substance P on the artinociceptive propoties of ketamine / 中国药理学通报

Aim To investigate the effect of spinal substance P on the antinociceptive propoties of ketamine. Methods Using behaviors and Fos expression technique,the effects of intrathecal administration (it) of substance P of different dose on the ketamine induced antinociception were observed in the formalin test of mice. Results Compared with NS group, the amount of time that mice spent licking the injected paw was dose-dependently decreased in 20 and 30 mg?kg -1 groups(P

Effect of Naloxone of Different Dosage on c-fos Expression in Hippocampus Induced by Repeated Febrile Seizures / 实用儿科临床杂志

Objective To investigate the effect of naloxone on c-fos expression in hippocampus induced by repeated febrile seizures(FS).Methods Warm water induced rat FS model was developed in this study. Each rat was induced 7 febrile seizures with the interval of one day. Naloxone-treated rats and FS control rats received injection of naloxone(1 mg/kg,2 mg/kg) or saline once FS occurrence every 2 day respectively. All rats were sacrificed 24 hours after the last seizure. In hippocampus, c-fos expression distribution and semi-quantitative analysis was determined by immuhischemical staining measure and western-blotting respectively.Results Compared with FS control group, naloxone treatment could significantly relieve c-fos expression in hippocampus induced by repeated FS, mainly in dentate gyrus(DG) and CA3 region. The comparison between 1 mg/kg and 2 mg/kg naloxone-treated group showed that 2 mg/kg naloxone could reduce c-fos positive expression more significantly.Conclusion Naloxone of proper dosage may significantly alleviate c-fos expression after repeated FS ,which further proved its antiepileptic function and also implied that endogenous opioid may be involved in the regulation of c-fos expression during seizure.