The Effect of Peripheral CRF Peptide and Water Avoidance Stress on Colonic and Gastric Transit in Guinea Pigs

Functional dyspepsia (FD) and irritable bowel syndrome (IBS) are common gastrointestinal (GI) diseases; however, there is frequent overlap between FD and IBS patients. Emerging evidence links the activation of corticotropin releasing factor (CRF) receptors with stress-related alterations of gastric and colonic motor function. Therefore, we investigated the effect of peripheral CRF peptide and water avoidance stress (WAS) on upper and lower GI transit in guinea pigs. Dosages 1, 3, and 10 µg/kg of CRF were injected intraperitoneally (IP) in fasted guinea pigs 30 minutes prior to the intragastric administration of charcoal mix to measure upper GI transit. Colonic transits in non-fasted guinea pigs were assessed by fecal pellet output assay after above IP CRF doses. Blockade of CRF receptors by Astressin, and its effect on GI transit was also analyzed. Guinea pigs were subjected to WAS to measure gastrocolonic transit in different sets of experiments. Dose 10 µg/kg of CRF significantly inhibited upper GI transit. In contrast, there was dose dependent acceleration of the colonic transit. Remarkably, pretreatment of astressin significantly reverses the effect of CRF peptide on GI transit. WAS significantly increase colonic transit, but failed to accelerate upper GI transit. Peripheral CRF peptide significantly suppressed upper GI transit and accelerated colon transit, while central CRF involved WAS stimulated only colonic transit. Therefore, peripheral CRF could be utilized to establish the animal model of overlap syndrome.

Evaluation of the effect of natural peptide 'Urocortin' on corticotrophin releasing factor (CRF) receptor expression in ND7/23 cells

CRF receptors are involved in the stress management of the cells and are believed to have a cytoprotective role in the body. CRF receptors have been reported to be potential drug targets for the treatment of neurodegenerative disorders. The cell line used in the study is ND7/23 (mouse neuroblastoma and rat dorsal root ganglion neuron hybridoma). The aim of the study was to confirm the expression of CRF receptors in ND7/23 cells and to determine if urocortin (Ucn) can enhance the expression of CRF receptors. ND7/23 cells were cultured in RPMI 1640 media and cells grown after the second passage were used for the experiments. RNA was extracted from the cells and amplified by RT-PCR to confirm the presence of CRF receptors. The cells were then subjected to oxidative stress by hydrogen peroxide (0.00375%) and divided into two groups i.e. control and Ucn (10-8 μM) treated. Later RNA was extracted from both group of cells and PCR was performed. Finally, densitometry analysis was conducted on the agarose gel to determine the quantity of PCR product formed. PCR experiment confirmed the expression of both CRF-R1 and CRF-R2 in the cell line, but CRF-R1 was found to be expressed more strongly. Densitometry analysis of the PCR product and calculation of the relative expression of CRF receptors indicated a higher level of expression of CRF receptors in samples treated with Ucn as compared to those that were kept untreated. The results indicate that Ucn may be useful for the management of neuro-degenerative disorders and further studies may be carried out to establish its use as a therapeutic agent.

Receptores de CRF estão envolvidos na gestão do estresse das células e são acreditados para ter um papel de cito-proteção no organismo. Os receptores do CRF têm sido relatados como alvos potenciais de fármacos para o tratamento de doenças neurodegenerativas. A linhagem celular utilizada no estudo é ND7/23 (neuroblastoma de camundongo e hibridoma de raíz dorsal do neurônio ganglionar de rato). O objetivo do estudo foi confirmar o que a expressão de receptores de CRF em células ND7/23 determinar se urocortina (Ucn) pode aumentar a expressão de receptores de CRF. Cultivaram-se células ND7/23 em meio RPMI 1640 e as células que cresceram após a segunda passagem foram usadas para os experimentos. O RNA foi extraído células e amplificado por RT-PCR para confirmar a presença de receptores de CRF. As células foram, então, submetidas a estresse oxidativo por peróxido de hidrogênio (0.00375 %) e divididas em dois grupos, ou seja, controle e tratadas com UCN (10-8 µM). Em seguida, o RNA foi extraído de ambos os grupo de células e realizou-se o PCR. Finalmente, realizou-se análise densitométrica em gel de agarose para determinar a quantidade de produto formado por PCR. O PCR confirmou a expressão de CRF-R1 e CRF-R2 na linhagem celular, mas o CRF-R1 expresso mais fortemente. A análise densitométrica do produto de PCR e o cálculo da expressão relativa de receptores de CRF indicaram um nível mais elevado de expressão de receptores de CRF em amostras tratadas com Ucn, em comparação com aqueles sem tratamento. Os resultados indicam que a Ucn pode ser útil no tratamento de doenças neurodegenerativas e mais estudos podem ser realizados para estabelecer seu uso como agente terapêutico.

Reversal of CRF- and stress-induced anorexia by an ayurvedic formulation

Trikatu churna is one of the commonly used Ayurvedic formulations in the traditional system of medicine in India for the treatment of agnimandya, i.e. anorexia. Trikatu contains equal amounts of finely powdered rhizomes of Zingiber officinale Roscoe (Zingiberaceae) and fruits of Piper longum L. and Piper nigrum L. (Piperaceae). The chief objective of the study was to determine the antianorectic effects of three drugs individually and to compare these effects with the effect of Trikatu. The activity of the drugs was studied after anorexia was induced in rats by (1) physical stress arising from immobilization for 60 min; (2) intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS, 100 μg/kg body weight); and (3) intraperitoneal administration of fluoxetine (8 mg/kg body weight). Similar doses of the extracts were tested on freely feeding rats and on rats that had been deprived of food for 20 h. Corticotrophin-releasing factor (CRF, 0.3 μg/rat) can induce anxiogenic-like behavior and reduced food intake. This model was also studied, and the results were compared. The components of Trikatu churna failed to individually reverse the inhibition of feeding. In contrast, Trikatu churna pretreatment reversed stress-, fluoxetine- and CRF-induced anorexia. The study provides strong evidence of the synergistic action of Ayurvedic formulas and also proves the ability of Trikatu churna to reduce stress and CRF-induced anorexia.

Effect of Berberine on Depression- and Anxiety-Like Behaviors and Activation of the Noradrenergic System Induced by Development of Morphine Dependence in Rats

The purpose of this study was to evaluate whether berberine (BER) administration could attenuate depression- and anxiety-like behaviors and increase corticotrophin-releasing factor (CRF) and tyrosine hydroxylase (TH) expression following chronic morphine withdrawal in rats. Male rats were exposed to chronic, intermittent, escalating morphine (10~50 mg/kg) for 10 days. After the last morphine injection, depression- and anxiety-like beahvior associated with morphine discontinuation persisted for at least three days during withdrawal without any change in ambulatory activity. Daily BER administration significantly decreased immobility in the forced swimming test and increased open-arm exploration in the elevated plus maze test. BER administration also significantly blocked the increase in hypothalamic CRF expression and TH expression in the locus coeruleus (LC) and the decrease in hippocampal brain-derived neurotrophic factor (BDNF) mRNA expression. Taken together, these findings demonstrated that BER administration significantly reduced morphine withdrawal-associated behaviors following discontinuation of repeated morphine administration in rats, possibly through modulation of hypothalamic CRF and the central noradrenergic system. BER may be a useful agent for treating or alleviating complex withdrawal symptoms and preventing morphine use relapses.

Changes of hypothalamus corticotropin releasing factor levels in children with acute brain injury / 中国小儿急救医学

Objective To explore the changes of corticotropin releasing factor (CRF) levels secreted by hypothalamus neuron in children with acute brain injury. Methods Fifty-one intracranial-infection children with brain injury and 11 intracranial-noninfection children with brain injury were chosen from pediatric intensive care unit of our hospital. Severities of their brain damage were evaluated by Glasgow score,and CRF level in cerebrospinal fluid (CSF) and serum TNF-α and IL-6 levels were measured by radioimmunoassay. Results There was no significant difference of Glasgow scores between the intracranial infection group and intracranial-noninfection group ( P = 0. 302 6 ), CSF CRF level of intracranial infection group was significantly lower than that of intracranial-noninfection group ( P ＜ 0. 01 ), serum TNF-α and IL-6 levels of intracranial infection group were significantly higher than those of intracranial-noninfection group ( P ＜ 0. 01,P ＜0. 001 ). As comparing to the children with Glasgow score of 6 ～ 7, the levels of CSF CRF and serum TNF-α and IL-6 in children with Glasgow score of 4 ～ 5 were significantly increased ( P ＜ 0. 05, P ＜ 0. 001 ).Conclusion CSF CRF level of the children with acute brain injury is changing, which may be concerned with the secretion of hypothalamus CRF neuron stimulated by TNF-α, IL-6 and hypoxia stress in children with brain injury.

Changes of plasma corticotrophin releasing factor levels in the young rats with hypoxic-ischemic brain damage / 中国小儿急救医学

Objective To explore the changes of plasma corticotrophin releasing factor (CRF) levels in the young rats with hypoxic-ischemic brain damage.Methods Two hundred and forty young rats were randomly divided into three groups:hypoxic-ischemic brain damage group ( model group,n =80),sham-operated group ( n =80),and normal control group ( n =80).The plasma CRF levels of rats in three groups were detected at 1 h,3 h,6 h,12 h,l d,3 d,5 d and 18 d after hypoxia-ischemia,per ten rats for each time point.Plasma CRF levels were measured by radioimmunoassay.Results Plasma CRF levels of model group,shamoperated group and normal control group showed no significant difference in the young rats after 1 h,3 h,6 h,12 h of hypoxia-ischemia ( P ＞ 0.05 ).But plasma CRF levels in the model group were respectively significantly lower than those of sham-operated group and normal control group after 1 d and 3 d of hypoxia-ischemia ( P ＜0.001 ),and then recovered to the control group levels after 5 d and 18 d of hypoxia-ischemia ( P ＞0.05 ).Conclusion Hypoxia-ischemia affects plasma CRF levels in the young rats,which is related with the duration after hypoxia-ischemia.

Inhibition of visceral hypersensitivity in irritable bowel syndrome model rat by intrathecal administration of corticotrophin releasing factor / 中华行为医学与脑科学杂志

Objective To investigate whether intrathecal administration of corticotrophin releasing factor(CRF) has an efficacy on visceral hypersensitivity in irritable bowel syndrome model rat.Methods Thirty rats were randomly divided into three groups(n=10 ).After establishment of irritable bowel syndrome rat model were intrathecal injected with CRF or preemptive peritoneal injected with CP-154526,which is inhibitor of CRF-1 receptor,and the control group to give saline.After experiment all rat with the method of rectal balloon distention,the perception thresholds and the number of abdominal withdrawal reflexes (AWR) of different balloon volume were observed.Results The perception threshold of intrathecal administration of CRF group was(0.62±0.10)ml and higher than other two groups [(0.52±0.09)ml,(0.56±0.08)ml;F=3.25,P＜0.05].At the same time,the number of AWR to the lower balloon content (1.0 ml) was(9.10±1.97)in intrathecal administration of CRF group slightly lower than other two groups[(14.4±1.71),(15.6±2.32);F=29.4,P＜0.01],but no difference was found to the higher balloon content (1.5 ml and 2.0 ml).Besides,the areas and OD value of c-fos positive neurons in cornu posterius medullae spinalis in group with intrathecal administration of CRF were significantly lower than other two groups (P＜0.05).Conclusion Intrathecal administration of CRF can degrade the visceral hyperensitivity in irritable bowel syndrome model rat,and lower expression of c-fos in CNS is probably involved in the process.