Activation and blockade of 5-HT4 receptors in the dorsal hippocampus enhance working and hippocampus-dependent memories in the unilateral 6-hydroxydopamine lesioned rats.

Cognitive dysfunction is a common symptom in Parkinson's disease (PD). Serotonin4 (5-HT4) receptors are richly expressed in the dorsal hippocampus (dHIPP) and play an important role in cognitive activities. However, the mechanism underlying the role of dHIPP 5-HT4 receptors in PD-related cognitive dysfunction remains unclear. Here we found that unilateral 6-hydroxydopamine lesions of the medial forebrain bundle increased the protein expression of 5-HT4 receptors in the dHIPP, decreased hippocampal theta rhythm, and impaired working memory and hippocampus-dependent memory in the T-maze and hole-board test, respectively. Both activation and blockade of dHIPP 5-HT4 receptors (agonist BIMU8 and antagonist GR113808) improved working memory and hippocampus-dependent memory in the lesioned rats, but not in sham rats. Activation of dHIPP 5-HT4 receptors increased hippocampal theta rhythm in the lesioned rats. The neurochemical studies showed that injection of BIMU8, GR113808 or GR113808/BIMU8 in the dHIPP increased the levels of dopamine in the medial prefrontal cortex (mPFC), dHIPP and amygdala, and the level of 5-HT in the amygdala in the lesioned rats, but not in sham rats. Injection of GR113808 or GR113808/BIMU8 into the dHIPP also increased the levels of noradrenaline in the mPFC, dHIPP and amygdala only in the lesioned rats. These results suggest that activation or blockade of dHIPP 5-HT4 receptors may improve the cognitive impairments in parkinsonian rats, which may be due to the increase of hippocampal theta rhythm, up-regulated expressions of 5-HT4 receptors in the dHIPP and the changes in the levels of monoamines in the relative brain areas.

High expression of Kruppel-like factor 4 as a predictor of poor prognosis for cervical cancer patient response to radiotherapy.

PURPOSE: The aim of this study was to explore the associations of Kruppel-like factor 4 expression with sensitivity to radiation therapy in locally advanced cervical squamous cell carcinoma patients. METHODS: The records of 117 locally advanced cervical squamous cell carcinoma patients were retrospectively reviewed, and Kruppel-like factor 4 expression in cervical carcinoma tissues was examined by immunohistochemical staining. The associations of Kruppel-like factor 4 expression with clinicopathological parameters were analyzed. Survival time was analyzed using Kaplan-Meier analysis and a Cox regression model. RESULTS: Patients being resistant to radiation therapy were associated with advanced International Federation of Gynecology and Obstetrics stage, tumor diameter (>4 cm), and poor differentiation grade. The high Kruppel-like factor 4 expression level was significantly related to resistance to radiation therapy, including radiation therapy non-response, local recurrence, and distant metastasis. The high Kruppel-like factor 4 expression level was also significantly related to the advanced International Federation of Gynecology and Obstetrics stage and poor differentiation grade. Kaplan-Meier analysis indicates that locally advanced cervical squamous cell carcinoma patients with high Kruppel-like factor 4 expression showed worse progression-free survival and overall survival. Univariate and multivariate Cox regression model analyses suggest that the high Kruppel-like factor 4 expression was one of the high-risk factors associated with poor prognosis in locally advanced cervical squamous cell carcinoma patients after radiation therapy. CONCLUSION: Our results suggest that the high Kruppel-like factor 4 expression can be used as a novel biomarker to predict radiation therapy resistance and poor prognosis for locally advanced cervical squamous cell carcinoma.

Anxiolytic effects of prelimbic 5-HT(1A) receptor activation in the hemiparkinsonian rat.

This study sought to assess whether unilateral lesions of the medial forebrain bundle (MFB) using 6-hydroxydopamine in rats are able to induce anxiety-like behaviors, the role of serotonin-1A (5-HT1A) receptors of the prelimbic (PrL) sub-region of ventral medial prefrontal cortex in the regulation of these behaviors, the density of 5-HT neurons in the dorsal raphe nucleus (DRN) and co-localization of 5-HT1A receptor and neuronal glutamate transporter EAAC1-immunoreactive (EAAC1-ir) cells in the PrL. Unilaterally lesioning the MFB induced anxiety-like behaviors as measured by the open-field and elevated plus maze tests when compared to sham-operated rats. Intra-PrL injection of 5-HT1A receptor agonist 8-OH-DPAT (50, 100, and 500 ng/rat) decreased the percentage of time spent in the center of the open-field and percentages of open arm entries and open arm time in sham-operated rats, indicating the induction of anxiogenic responses, and administration of 5-HT1A receptor antagonist WAY-100635 (60, 120, and 240 ng/rat) showed anxiolytic effects. However, 8-OH-DPAT, at the same doses, increased the percentage of time spent in the center of the open-field and percentages of open arm entries and open arm time in the lesioned rats, indicating the induction of anxiolytic effects, and WAY-100635 produced anxiogenic responses. Unilateral MFB lesion decreased the density of 5-HT neurons in the DRN, and percentage of EAAC1-ir cells expressing 5-HT1A receptors in the PrL. These results suggest that unilateral lesions of the MFB in rats may induce anxiety-like behaviors, and activation of 5-HT1A receptors in the PrL has anxiolytic effects in the rat model of Parkinson's disease.

The response of juxtacellular labeled GABA interneurons in the basolateral amygdaloid nucleus anterior part to 5-HT2A/2C receptor activation is decreased in rats with 6-hydroxydopamine lesions.

Here we report that juxtacellular labeled GABA interneurons in the basolateral amygdaloid nucleus anterior part (BLA) of rats with 6-hydroxydopamine lesions of the substantia nigra pars compacta (SNc) showed a more burst-firing pattern, while having no change in the firing rate. In sham-operated and the lesioned rats, systemic administration of 5-HT(2A/2C) receptor agonist DOI produced excitation, inhibition and unchanged in the firing rate of the interneurons, and the mean response of DOI was excitatory. However, cumulative dose producing excitation in the lesioned rats was higher than that of sham-operated rats. The local administration of DOI in the BLA also produced three types of responses in two groups of rats. Furthermore, the local administration of DOI excited the interneurons in sham-operated rats, whereas the mean firing rate of the interneurons in the lesioned rats was not affected at the same dose. The excitatory effect of the majority of the interneurons after systemic and local administration of DOI was not reversed by the selective 5-HT(2C) receptor antagonist SB242084, and the inhibitory effect of DOI in all the interneurons examined was reversed by GABA(A) receptor antagonist picrotoxinin. The SNc lesion in rats did not change the density of GAD67/5-HT(2A) receptor co-expressing neurons in the BLA. These results indicate that the SNc lesion changes the firing activity of BLA GABA interneurons. Moreover, DOI regulated the firing activity of the interneurons mainly through activation of 5-HT(2A) receptor, and the lesion led to a decreased response of the interneurons to DOI, which attributes to dysfunction of 5-HT(2A) receptor on these interneurons.

Osthole protects lipopolysaccharide-induced acute lung injury in mice by preventing down-regulation of angiotensin-converting enzyme 2.

The renin-angiotensin-aldosterone system (RAAS) plays an important role in the pathogenesis of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Angiotensin converting enzyme 2 (ACE2) plays a protective role in acute lung injury. Osthole, a natural coumarin derivative extracted from traditional Chinese medicines, is known to have anti-inflammatory effect, but the effect of osthole on the ALI is largely unknown. The aim of this study is to explore whether and by what mechanisms osthole protects lipopolysaccharide(LPS)-induced acute lung injury. Herein, we found that osthole had a beneficial effect on LPS-induced ALI in mice. As revealed by survival study, pretreatment with high doses of osthole reduced the mortality of mice from ALI. Osthole pretreatment significantly improved LPS-induced lung pathological changes, reduced lung wet/dry weight ratios and total protein in BALF. Osthole also inhibited the release of inflammatory mediators TNF-α and IL-6. Meanwhile, osthole markedly prevented the loss of ACE2 and Ang1-7 in lung tissue of ALI mice. ACE2 inhibitor blocked the protective effect of osthole in NR 8383 cell lines. Taken together, our study showed that osthole improved survival rate and attenuated LPS-induced ALI and ACE2 may play a role in it.

Changes in firing rate and pattern of GABAergic neurons in subregions of the substantia nigra pars reticulata in rat models of Parkinson's disease.

The substantia nigra pars reticulata (SNr) plays a key role in the pathophysiology of Parkinson's disease (PD). It has been well documented that the SNr is not a homogeneous structure, and the lateral and medial subregions of the SNr receive different projections from the sensorimotor and limbic striatum, respectively. However, specific changes in firing activity of SNr subregions in PD remain unclear. In the present study, the spontaneous firing activity of GABAergic neurons in the lateral and medial SNr of rats with unilateral 6-hydroxydopamine lesions of the substantia nigra pars compacta (SNc) or medial forebrain bundle (MFB) has been examined. Extracellular recordings indicated that the firing rate of lateral SNr neurons increased significantly and firing pattern of these neurons changed towards more irregular and bursty after SNc or MFB lesions compared to normal rats. In contrast, the firing rate and pattern of medial SNr neurons in rats with SNc lesions were unaltered when compared with that of normal rats. However, MFB lesions in rats decreased the firing rate of medial SNr neurons and firing pattern of these neurons changed towards more bursty. In addition, SNc lesions in rats increased the firing rate of the neurons with regular and irregular firing patterns within lateral but not in medial SNr, while the firing rate of the neurons within lateral and medial SNr with each firing pattern was not altered after MFB lesions. These results suggest that GABAergic neurons of SNr subregions have differential change of firing activity in the pathophysiology of PD.

Noradrenergic lesion of the locus coeruleus increases the firing activity of the medial prefrontal cortex pyramidal neurons and the role of alpha2-adrenoceptors in normal and medial forebrain bundle lesioned rats.

Degeneration of noradrenergic neurons in the locus coeruleus (LC) and dysfunction of the prefrontal cortex were regarded as playing a specific role in the occurrence of non-motor symptoms in Parkinson's disease. The present study examined the spontaneous firing rate and firing pattern of medial prefrontal cortex (mPFC) pyramidal neurons, and effects of alpha(2)-adrenoceptor agonist UK-14,304 and antagonist yohimbine on the neuronal activity in rats with 6-hydroxydopamine lesions of the LC, medial forebrain bundle (MFB) and with combined MFB and LC lesions. The firing rate of mPFC pyramidal neurons in rats with lesions of the LC and with combine LC and MFB lesions is significantly higher than that of normal and MFB-lesioned rats and the firing pattern of these neurons in rats with lesions of the LC and with combine LC and MFB lesions also changed significantly towards more regular compared with normal and MFB-lesioned rats. The local administration of UK-14,304 in the mPFC inhibited the firing activity of the pyramidal neurons in normal rats and rats with lesions of the LC, MFB and with combined LC and MFB lesions, while yohimbine increased the firing activity of the pyramidal neurons. These results indicate that the lesions of the LC lead to hyperactivity of mPFC pyramidal neurons in normal and MFB-lesioned rats, and the postsynaptic alpha(2)-adrenoceptors may partially mediate the inhibitory effects of LC-noradrenergic system on the firing activity of pyramidal neurons in the mPFC, suggesting that LC-noradrenergic system plays an important role in the functional disorders of mPFC in Parkinson's disease.

Noradrenergic lesion of the locus coeruleus increases apomorphine-induced circling behavior and the firing activity of substantia nigra pars reticulata neurons in a rat model of Parkinson's disease.

The role of noradrenergic depletion of the locus coeruleus (LC) in the pathophysiology of Parkinson's disease (PD) is still unclear. In the present study, apomorphine-induced circling behavior and extracellular firing activity of substantia nigra pars reticulata (SNr) neurons were examined in rats with unilateral 6-hydroxydopamine lesions of the LC, substantia nigra pars compacta (SNc) and with combined SNc and LC lesions. A moderate contralateral circling was observed in rats with LC lesions after apomorphine. Moreover, the circling behavior was obviously increased by further lesions of LC in SNc-lesioned rats. Extracellular recordings indicated that the firing rate of SNr neurons increased significantly and the firing pattern of these neurons also changed towards more irregular and bursty after SNc lesioning as compared to sham-lesioned rats, while the firing rate and pattern were unaffected in rats with simple lesions of the LC. However, the firing rate of SNr neurons in rats with combined LC and SNc lesions increased significantly when compared to that of rats with simple lesions of the SNc, although the firing pattern was not altered. Furthermore, SNc lesions in rats increased the firing rate of SNr neurons with irregular firing pattern, and additional LC lesions in SNc-lesioned rats increased the firing rate of SNr neurons with regular and irregular firing pattern. These results indicate that lesions of the LC intensify apomorphine-induced circling behavior and lead to a further hyperactivity of SNr neurons in a rat model of PD, suggesting that LC-noradrenergic system is involved in the motor dysfunction of PD.

Unilateral lesion of the nigrostriatal pathway decreases the response of interneurons in medial prefrontal cortex to 5-HT 2A/2C receptor stimulation in the rat.

The aim of the present study was to investigate changes in the firing rate and pattern of interneurons in the medial prefrontal cortex (mPFC), and effects of 5-HT(2A/2C) receptor agonist DOI and antagonist ritanserin, and the selective 5-HT(2C) receptor antagonist SB 242084 on the neuronal firing in rats with 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta (SNc) by extracellular recording in vivo. The lesion of the SNc decreased the firing rate of the interneurons compared to sham-lesioned rats, and firing pattern of these interneurons changed toward a more burst-firing. Administration of DOI (20-320 microg/kg, i.v.) dose-dependently increased the firing rate of all interneurons examined in sham-lesioned and the 6-OHDA-lesioned rats. The excitation was significant at doses higher than 40 microg/kg and 320 microg/kg in sham-lesioned and the 6-OHDA-lesioned rats, respectively. This dose, which produced marked effect in the 6-OHDA-lesioned rats, was much higher than that of sham-lesioned rats. The local application of DOI (5 microg) in mPFC increased the firing rate of the interneurons in sham-lesioned rats, while having no effect on the firing rate in the 6-OHDA-lesioned rats. The excitatory effect of DOI in sham-lesioned and the 6-OHDA-lesioned rats was completely or partially reversed by ritanserin or SB 242084. The results of our study show that lesion of the SNc leads to a decrease in the firing rate of interneurons in mPFC and fire with a more burst pattern, and decreased response of the interneurons to DOI in rat.

In vivo effects of activation and blockade of 5-HT(2A/2C) receptors in the firing activity of pyramidal neurons of medial prefrontal cortex in a rodent model of Parkinson's disease.

In the present study, we examined changes in the firing rate and firing pattern of pyramidal neurons in medial prefrontal cortex (mPFC), and the effects of 5-HT(2A/2C) receptor agonist DOI and antagonist ritanserin on the neuronal firing in rats with 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta by using extracellular recording. The unilateral lesion of the nigrostriatal pathway significantly increased the mean firing rate of pyramidal neurons compared to sham-operated rats, and the firing pattern of these neurons also changed significantly towards a more bursty one. Systemic administration of DOI (20-320 microg/kg, i.v.) increased the mean firing rate of pyramidal neurons in sham-operated and the lesioned rats. The excitation was significant only at doses higher than 160 microg/kg and 320 microg/kg in sham-operated and the lesioned rats, respectively. In addition, the local application of DOI, 5 microg, in mPFC inhibited the firing rate of pyramidal neurons in sham-operated rats, while having no effect on firing rate in the lesioned rats. After treatment with GABAA receptor antagonist picrotoxinin, the local application of DOI, at the same dose, increased the mean firing rate of the neurons in sham-operated rats; however, DOI did not alter the firing activity of the neurons in the lesioned rats. These results indicate that the lesion of the nigrostriatal pathway leads to hyperactivity of pyramidal neurons in mPFC, and the decreased response of pyramidal neurons to DOI, suggesting dysfunction of 5-HT2A and 5-HT2C receptors on pyramidal neurons and GABAergic interneurons in the 6-OHDA-lesioned rats.

[Change of oxygen free radical in reversing multidrug-resistance of human leukemic cell line HL-60/ADM by cyclosporin A].

This study was aimed to evaluate the reversed effects of cyclosporin A (CsA) on multidrug resistance (MDR) of human leukemic cell line HL-60/ADM, and to investigate the relationship of the oxygen free radical content between HL-60/ADM cells and the reversed HL-60/ADM cells (HL-60/ADM + CsA). The cytotoxicity and the reversed effects of CsA on multidrug resistance of human leukemic cell line HL-60/ADM were studied by MTT, flow cytometry (FCM) and immunohistochemical assay; the oxygen free radical for HL-60/ADM and HL-60/ADM + CsA cell lines were detected by colorimetric method. The results showed that the CsA less than 4 microg/ml had no significant cytotoxicity on HL-60/ADM, while the cytotoxicity was rised with CsA concentration increasing; And CsA (4 microg/ml) combined with ADM (1 microg/ml) could obviously restrain the growth of HL-60/ADM cells (p < 0.001). The P-gp expression of HL-60/ADM decreased obviously after exposure to CsA (4 microg/ml) for 72 hours, at the same cell conditions, MDA concentration of the reversed groups (HL-60/ADM + CsA cells) was higher than that of the control groups (HL-60/ADM cells) (p < 0.05), while the levels of SOD and GSH in the reversed groups were significantly lower than that in control groups (p < 0.001). It is concluded that MDR of HL-60/ADM can be reversed effectively by low dose of CsA, the level of oxygen free radical increases and the activity of antioxidants decreases in the reversed cells. Oxygen free radicals may be involved in this reverse process, which thereby lead to the cell death.

The firing activity of presumed cholinergic and non-cholinergic neurons of the pedunculopontine nucleus in 6-hydroxydopamine-lesioned rats: an in vivo electrophysiological study.

Several studies have shown that the neuronal activity of the pedunculopontine nucleus is increased in Parkinson's disease. In the present study, the changes were examined in the firing rate and firing pattern of presumed cholinergic and non-cholinergic neurons in the pedunculopontine nucleus of 6-hydroxydopamine-lesioned rats by using extracellular recording. In the lesioned rats, the mean firing rate of both presumed cholinergic and non-cholinergic neurons in the pedunculopontine nucleus increased significantly compared to normal rats. With regard to firing pattern, the majority of presumed cholinergic and non-cholinergic neurons fired regularly in normal rats. After substantia nigra pars compacta-lesion, the percentage of presumed non-cholinergic neurons exhibiting irregular pattern increased significantly compared to normal rats, while having no significant change in the firing pattern of presumed cholinergic neurons. Collectively, these results indicate that the presumed cholinergic and non-cholinergic neurons in the pedunculopontine nucleus are overactive in 6-hydroxydopamine-lesioned rats, particularly, presumed non-cholinergic neuron firing is more irregular, which suggests that the firing activity of presumed cholinergic and non-cholinergic neurons is affected by the different afferents from the basal ganglia and related structures.

[The examination of ultraweak luminescence of HL-60 cells and adriamycin-resistant HL-60/ADM cells].

AIM: To explore the relationship between the ultraweak luminescence and adriamycin resistantance in human leukemic cells (HL-60) and human adriamycin resistant leukemic cells (HL-60/ADM). METHODS: MTT colorimetry, flow cytometry (FCM), growth curve and immunohistochemical staining were used to detect the sensitivity of HL-60 and HL-60/ADM cells to ADM, the change of cell cycle and the expression of P-glycoprotein(P-gp170). The intensity of the ultraweak luminescence of HL-60 cells and HL-60/ADM cells was examined by the IFFM-D chemiluminescence instrument. RESULTS: The sensitivity of HL-60/ADM cells to ADM was distinctly lower than that of HL-60 cells. The percentage of HL-60/ADM cells in G(0)/G(1) was 44.80%+/-1.97% and that in G(2)/M phase was 9.90%+/-0.27%, which was both higher than that of HL-60 cells. The percentage of HL-60/ADM cells in S phase was 45.30%+/-1.93%, which was lower than that of HL-60 cells. The doubling time of HL-60/ADM cells was 1.8 times as long as that of HL-60 cells. The expression of P-gp170 was positive in HL-60/ADM cells but negative in HL-60 cells.Treated with 10(-4) mol/L luminol and 3 mL/L H(2)O(2) and under four different cell concentration (8x10(7)/L,1x10(8)/L,1.26x10(8)/L, 2.73x10(8)/L), the intensity of ultraweak luminescence of HL-60/ADM cells was distinctly lower than that of HL-60 cells (P<0.05). CONCLUSION: The lower sensitivity to ADM, longer doubling time and the expression of P-gp170 showed the drug resistance of HL-60/ADM cells. With the obtaining of drug resistance, ultraweak luminescence intensity was lower in HL-60/ADM cells than that of HL-60 cells. It showed that the decreasing of intensity of ultraweak luminescence could be an index of examining drug-resistantce of tumor cells.