Trial of Contralateral Seventh Cervical Nerve Transfer for Spastic Arm Paralysis.

BACKGROUND: Spastic limb paralysis due to injury to a cerebral hemisphere can cause long-term disability. We investigated the effect of grafting the contralateral C7 nerve from the nonparalyzed side to the paralyzed side in patients with spastic arm paralysis due to chronic cerebral injury. METHODS: We randomly assigned 36 patients who had had unilateral arm paralysis for more than 5 years to undergo C7 nerve transfer plus rehabilitation (18 patients) or to undergo rehabilitation alone (18 patients). The primary outcome was the change from baseline to month 12 in the total score on the Fugl-Meyer upper-extremity scale (scores range from 0 to 66, with higher scores indicating better function). Results The mean increase in Fugl-Meyer score in the paralyzed arm was 17.7 in the surgery group and 2.6 in the control group (difference, 15.1; 95% confidence interval, 12.2 to 17.9; P<0.001). With regard to improvements in spasticity as measured on the Modified Ashworth Scale (an assessment of five joints, each scored from 0 to 5, with higher scores indicating more spasticity), the smallest between-group difference was in the thumb, with 6, 9, and 3 patients in the surgery group having a 2-unit improvement, a 1-unit improvement, or no change, respectively, as compared with 1, 6, and 7 patients in the control group (P=0.02). Transcranial magnetic stimulation and functional imaging showed connectivity between the ipsilateral hemisphere and the paralyzed arm. There were no significant differences from baseline to month 12 in power, tactile threshold, or two-point discrimination in the hand on the side of the donor graft. RESULTS: The mean increase in Fugl-Meyer score in the paralyzed arm was 17.7 in the surgery group and 2.6 in the control group (difference, 15.1; 95% confidence interval, 12.2 to 17.9; P<0.001). With regard to improvements in spasticity as measured on the Modified Ashworth Scale (an assessment of five joints, each scored from 0 to 5, with higher scores indicating more spasticity), the smallest between-group difference was in the thumb, with 6, 9, and 3 patients in the surgery group having a 2-unit improvement, a 1-unit improvement, or no change, respectively, as compared with 1, 6, and 7 patients in the control group (P=0.02). Transcranial magnetic stimulation and functional imaging showed connectivity between the ipsilateral hemisphere and the paralyzed arm. There were no significant differences from baseline to month 12 in power, tactile threshold, or two-point discrimination in the hand on the side of the donor graft. CONCLUSIONS: In this single-center trial involving patients who had had unilateral arm paralysis due to chronic cerebral injury for more than 5 years, transfer of the C7 nerve from the nonparalyzed side to the side of the arm that was paralyzed was associated with a greater improvement in function and reduction of spasticity than rehabilitation alone over a period of 12 months. Physiological connectivity developed between the ipsilateral cerebral hemisphere and the paralyzed hand. (Funded by the National Natural Science Foundation of China and others; Chinese Clinical Trial Registry number, 13004466 .).

Rapid adaptation effect of N170 for printed words.

Faces and written words are two of the most familiar types of visual patterns with the brain's selective response of N170 component in early perception. Using ERP adaptation paradigms, studies have found the N170 response is reduced when there is repeated presentation of upright faces relative to a control condition. In contrast to these well-established features of the face-related N170 adaptation effect, the characteristics of the N170 adaptation effect for printed words are less clear. The goal was to investigate the ERP adaptation effects of printed language (English words and Chinese characters) in a short ISI (200 msec.) adaptation paradigm. The present study showed that both alphabetic words and non-alphabetic words could produce a rapid N170 adaptation effect. Objects of expertise (e.g. words and faces) can produce a rapid N170 adaptation effect but other objects (e.g., houses) cannot, indicating that the specific stimuli have some specific mechanisms for the rapid N170 adaptation.

[Measure of sunscreen cream transmittance in UV wave range and analysis of sun protection effect].

SPF and PA index present the resistance ability of sunscreen to UVA (Ultraviolet A) and UVB (Ultraviolet B) respectively. The present article focuses on the research on the relationship between ultraviolet transmittance and sunscreen ability based on definition of sunscreen efficiency and a simple and significant result was obtained by deducing. The technique we applied is spectral analysis dealing with ethanol-ethyl ether mixed solvent by ultraviolet and visible light spectrophotometer. We measured the UVA and UVB transmittance of 69 common sunscreen samples. The measurement result shows that spectral analysis method could differentiate sunscreens with different SPF and PA and identify whether the parameter value marked is accurate. So, an effective method is provided for the measurement of SPF and PA value. If different types of ultraviolet absorbent or UV scattering dose is added in sunscreen, the authors can distinguish them easily through the shape of the transmittance curve. In our sunscreen samples measured, domestic brands and imported brands are classified into two categories. By comparing the experimental results, the authors found that the domestic sunscreen and import sunscreen have no significant difference in sun block efficiency as long as the authors adopt the product of qualified manufacturer.

Post-training intra-basolateral amygdala infusions of norepinephrine block sevoflurane-induced impairment of memory consolidation and activity-regulated cytoskeletal protein expression inhibition in rat hippocampus.

Considerable evidence indicates that the noradrenergic system of the basolateral amygdala (BLA) participates in the consolidation of various types of emotionally arousing memories. We previously reported that administration of an anesthetic-dose of sevoflurane immediately after continuous multiple-trail inhibition avoidance (CMIA) training impaired memory consolidation. This experiment investigated whether posttraining noradrenergic activation of the BLA is sufficient to reverse the memory impairing effect of sevoflurane. Adult male Sprague-Dawley rats received bilateral injections of norepinephrine (NE 0.3, 1.0, or 3.0 µg/0.5 µl) or normal saline (NS 0.5 µl) immediately after training in a CMIA paradigm. Subsequently, the rats were exposed to sevoflurane (2% inspired) or air for 2h. Norepinephrine produced a dose-dependent enhancement of memory consolidation on a 24-h retention test. The highest dose of NE tested (3.0 µg/0.5 µl) blocked sevoflurane-induced impairment of memory consolidation and reversed the inhibitory effect of sevoflurane on activity-regulated cytoskeletal protein (Arc) expression in the hippocampus 2h after training. These findings provide evidence that the mechanism mediating the memory-impairing effect of sevoflurane involves a network interaction between the BLA noradrenergic system and modulation of Arc protein expression in the hippocampus.

Change in subtle N170 specialization in response to Chinese characters and pseudocharacters.

The N170 effect is thought to reflect fast perceptual processing for visual words. While quite a few studies on developmental word-related coarse N170 specialization have been reported, little is known about the appearance of the subtle N170 specialization in processing logographic scripts by Chinese children. The present study investigated the changes of subtle N170 specialization for Chinese logographic script in 32 primary schoolchildren in Grades 2 and 6, and in 16 college students. Participants were required to perform a content-irrelevant color-matching task. The results showed that the subtle N170 specialization for Chinese characters had not emerged in Grade 2 children. Interestingly, both Chinese characters and pseudowords elicited larger N170 responses than stroke combinations in Grade 6 children and adults, which suggested that the subtle N170 specialization for Chinese characters associated with reading learning had achieved adult level in children by Grade 6.

[Application of laser Raman spectroscopy to hydrogen isotope analysis].

Analysis of laser Raman spectroscopy has turned into the efficient research method of substance structure and composition analysis. In the present paper, the principle of laser Raman spectroscopy and its characteristics of analysis method are introduced. Applicability of laser Raman spectroscopy to hydrogen isotope analysis is analyzed. The analytical applications of laser Raman spectroscopy method in radiation reaction of tritium, hydrogen isotope examination and quantitative analysis are presented from reported literature.

Activation of extracellular signal-regulated kinase in the anterior cingulate cortex contributes to the induction and expression of affective pain.

The anterior cingulate cortex (ACC) is implicated in the affective response to noxious stimuli. However, little is known about the molecular mechanisms involved. The present study demonstrated that extracellular signal-regulated kinase (ERK) activation in the ACC plays a crucial role in pain-related negative emotion. Intraplantar formalin injection produced a transient ERK activation in laminae V-VI and a persistent ERK activation in laminae II-III of the rostral ACC (rACC) bilaterally. Using formalin-induced conditioned place avoidance (F-CPA) in rats, which is believed to reflect the pain-related negative emotion, we found that blockade of ERK activation in the rACC with MEK inhibitors prevented the induction of F-CPA. Interestingly, this blockade did not affect formalin-induced two-phase spontaneous nociceptive responses and CPA acquisition induced by electric foot-shock or U69,593, an innocuous aversive agent. Upstream, NMDA receptor, adenylyl cyclase (AC) and phosphokinase A (PKA) activators activated ERK in rACC slices. Consistently, intra-rACC microinjection of AC or PKA inhibitors prevented F-CPA induction. Downstream, phosphorylation of cAMP response element binding protein (CREB) was induced in the rACC by formalin injection and by NMDA, AC and PKA activators in brain slices, which was suppressed by MEK inhibitors. Furthermore, ERK also contributed to the expression of pain-related negative emotion. Thus, when rats were re-exposed to the conditioning context for retrieval of pain experience, ERK and CREB were reactivated in the rACC, and inhibiting ERK activation blocked the expression of F-CPA. All together, our results demonstrate that ERK activation in the rACC is required for the induction and expression of pain-related negative affect.

[Experiment-time affects the cognitive behavior in aged Sprague-Dawley rats].

In order to investigate if the experiment-time affects cognitive performance in aged rats in different learning and memory behavioral tests, the aged Sprague-Dawley (SD) rats were divided into two groups randomly and subjected to open field test, Morris water maze test and social discrimination test. The experiment of one group was conducted in 8:00 - 11:00 AM (AM group), and the other group in 15:00 - 18:00 PM (PM group). PM group exhibited higher locomotor activity than AM group in the open field test. Compared with AM group rats, PM group rats had significantly shorter swimming distance and escape latency to find the platform in Morris water maze training session, but no significant difference in the swimming velocity was observed between the two groups. And in probe-test, PM group spent more time in target quadrant than AM group. These results revealed that PM group showed better spatial learning and memory abilities than AM group. However, there was no significant difference between the two groups in social investigation index in social discrimination test. These results show that experiment-time may affect cognitive performance in Morris water maze but not in social discrimination task in aged rats. And the results indicate that experiment-time affects cognitive performance of aged rats selectively in different learning and memory behavioral tasks.

Pre- and postsynaptic beta-adrenergic activation enhances excitatory synaptic transmission in layer V/VI pyramidal neurons of the medial prefrontal cortex of rats.

Norepinephrine exerts an important influence on prefrontal cortical functions. The physiological effects of beta-adrenoceptors (beta-ARs) have been examined in other brain regions. However, little is known about beta-AR regulation of synaptic transmission in the prefrontal cortex (PFC). The present study investigated beta-AR modulation of glutamate synaptic transmission in layer V/VI pyramidal cells of the medial PFC (mPFC) of rats. Our results show that 1) isoproterenol (ISO), a selective beta-AR agonist, increased the frequency of spontaneous and miniature excitatory postsynaptic currents (EPSC's); 2) ISO enhancement of miniature EPSC's (mEPSC's) frequency no longer appeared in the presence of the voltage-gated Ca(2+) channel blocker cadmium; 3) ISO enhanced the evoked excitatory postsynaptic currents (eEPSC's) mediated by non-N-methyl-D-aspartic acid receptors (non-NMDA-Rs) and NMDA-Rs. The ISO facilitation of non-NMDA-R eEPSC was blocked by the membrane-permeable cyclic adenosine monophosphate (cAMP) inhibitor Rp-adenosine 3',5'-cyclic monophosphorothioate triethylammonium salt (Rp-cAMPS); 4) ISO enhanced NMDA-induced current, with no effect on glutamate-induced non-NMDA-R current; 5) ISO enhancement of NMDA-R eEPSC and NMDA-induced current was blocked by intracellular application of Rp-cAMPS or the cAMP-dependent protein kinase (PKA) inhibitor PKI(5-24); and 6) ISO suppressed the paired-pulse facilitation of non-NMDA-R and NMDA-R eEPSC's. Taken together, these results provide the first electrophysiological demonstration that beta-AR activation facilitates excitatory synaptic transmission in mPFC pyramidal cells through pre- and postsynaptic mechanisms, probably via cAMP or cAMP/PKA signaling.

[Inhibitory effect of anterior cingulate cortex on spontaneous activity of thalamic ventrobasal nucleus neurons.].

The purpose of this study was to investigate the influence of electrical stimulation of anterior cingulate cortex (ACC) on spontaneous activity of neurons in thalamic ventrobasal nucleus (VB). Experiments were performed on 12 male Sprague-Dawley rats weighing 250-310 g (4-5 months old). According to Paxinos and Watson's coordinate atlas of the rat, the frontal and parietal cortical areas were exposed by craniotomy, the recording electrodes were then inserted into the VB (P 2.4-4.1 mm, R 2.0-3.5 mm, H 5.2-6.8 mm) and the stimulating electrodes into the ACC (A 1.1-3.0 mm, R 0.0-1.0 mm, H 1.5-2.4 mm). Single-unit activities were recorded extracellularly in the VB by glass micropipettes (impedance 3-8 MOmega) filled with 0.5 mol/L sodium acetate solution containing saturated Fast Green. To study the effects of ACC activation on the spontaneous activities of VB cells, single electrical pulse (0.2 ms duration) was delivered to the ACC by a concentric bipolar stainless steel electrode (0.32 mm outer diameter). An effective ACC stimulation was determined for each VB neuron by gradually increasing the current intensity from 0.1 mA until either a significant change in the spontaneous activity of the VB neuron was observed, or the current intensity reached 0.4 mA. The results showed that ACC stimulation significantly suppressed the spontaneous activities in 12 out of 53 VB neurons (22.6%). (1) After the stimulation was delivered to ACC, the spontaneous activities of different VB neurons were totally suppressed for different time span. (2) There was obvious dose-effect relevance between ACC stimulation intensity and their inhibitory effect. The duration of complete inhibition was prolonged with the increases in the intensity and number of stimulation impulses in ACC. (3) The stimulation in the ACC depressed the spontaneous activities of VB neurons in different forms and this inhibition exhibited an accumulative effect. All these results indicate that the stimulation of ACC exerts an inhibitory influence on the spontaneous activities of VB neurons.

Prefrontal modulation of tactile responses in the ventrobasal thalamus of rats.

Prefrontal cortex (PFC) has been implicated in modulation of sensory information processing in somatosensory cortex. However, it remains unclear whether or not PFC regulates sensory information in thalamus. In the present study, the effect of PFC stimulation on tactile responses of neurons in the ventrobasal thalamus (VB) of the rat was investigated by single-unit recording. PFC stimulation significantly enhanced the signal-noise ratio (tactile responses/background activities) in 16 out of 66 VB neurons (24.2%) that had receptive fields in fore or hind limbs. Such changes can be classified into three different categories: (1) PFC stimulation not only increased the tactile responses, but also suppressed the background activities of neurons (six neurons, 9.1%); (2) PFC stimulation only increased the tactile responses of neurons (five neurons, 7.6%); (3) PFC stimulation only suppressed the background activities of neurons (five neurons, 7.6%). Our results suggest that PFC also modulates somatosensory information at the thalamic level.

Upregulation of miR-137 reverses sorafenib resistance and cancer-initiating cell phenotypes by degrading ANT2 in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. More than 80% of patients with HCC are not good candidates for curative surgical resection due to advanced liver cirrhosis caused by underlying chronic hepatitis virus (B or C) infection. Sorafenib, an oral multikinase inhibitor, is the only approved agent for the treatment of advanced HCC. Although, sorafenib currently sets the new standard for advanced HCC treatment, tumor response rates are usually quite low. An understanding of the underlying mechanisms for sorafenib resistance is critical. In the present study, we found that adenine nucleotide translocator 2 (ANT2) was upregulated in sorafenib­resistant HCC Huh7 cells (Huh7-R) and its overexpression promoted sorafenib resistance. ANT2 induced the formation of cancer-initiating cell (CIC) phenotypes and promoted metastasis-associated traits in the Huh7 cells. Silencing of miR-137 upregulated ANT2 protein expression in the Huh7 cells. miR-137 was downregulated in the Huh7-R cells, compared with that in the Huh7 cells and its restoration reversed sorafenib resistance in the Huh7-R cells. Restoration of miR-137 inhibited formation of CIC traits and attenuated the abilities of migration and invasion in the Huh7-R cells. Moreover, we demonstrated that high-intensity focused ultrasound (HIFU) in unresectable HCC upregulated serum miR-137. Combining HIFU and sorafenib may be a wise option for advanced and unresectable HCC.

Verbal working memory-related functional connectivity alterations in boys with attention-deficit/hyperactivity disorder and the effects of methylphenidate.

OBJECTIVE: Few studies have investigated verbal working memory-related functional connectivity patterns in participants with attention-deficit/hyperactivity disorder (ADHD). Thus, we aimed to compare working memory-related functional connectivity patterns in healthy children and those with ADHD, and study effects of methylphenidate (MPH). METHOD: Twenty-two boys with ADHD were scanned twice, under either MPH (single dose, 10 mg) or placebo, in a randomised, cross-over, counterbalanced placebo-controlled design. Thirty healthy boys were scanned once. We used fMRI during a numerical n-back task to examine functional connectivity patterns in case-control and MPH-placebo comparisons, using independent component analysis. RESULTS: There was no significant difference in behavioural performance between children with ADHD, treated with MPH or placebo, and healthy controls. Compared with controls, participants with ADHD under placebo showed increased functional connectivity within fronto-parietal and auditory networks, and decreased functional connectivity within the executive control network. MPH normalized the altered functional connectivity pattern and significantly enhanced functional connectivity within the executive control network, though in non-overlapping areas. CONCLUSION: Our study contributes to the identification of the neural substrates of working memory. Single dose of MPH normalized the altered brain functional connectivity network, but had no enhancing effect on (non-impaired) behavioural performance.

[Three-dimensional ultrasound evaluation of the efficacy and safety of single-dose systemic or local methotrexate injection for tubal pregnancy].

OBJECTIVE: To compare the efficacy and safety of single-dose systemic and local injection of methotrexate (MTX) in the treatment of tubal pregnancy (TP). METHODS: The systemic group included 127 women with TP who received a single-dose MTX of 50 mg/m(2) given by intramuscular injection, and the local group included 118 women receiving single-dose MTX of 100 mg via local injection guided by three-dimensional (3D) ultrasound. The volume of ectopic masses and blood beta-human chorionic gonadotropin (beta-HCG) were measured before and after MTX administration. The TP was detected by 3D images reconstructed 3 months after MTX administration. RESULTS: The success rate of treatment was 100% in the local group, significantly higher than that of 91.34% in the systemic group. After the first week of MTX injection, the speed of the ectopic mass resolution was 0.85+/-0.04 cm(3)/d and 0.47+/-0.03 cm(3)/d in systemic group and local group respectively (P<0.05), and the time of the ectopic mass resolution was 27.66+/-12.77 d and 32.62+/-12.75 d, respectively (P<0.01). The rate of tubal deformity in the local group was significantly lower than that in the systemic group. CONCLUSION: Local injection of MTX under ultrasound guidance is safe, efficient and reliable for conservative management of unruptured TP, which is superior to systemic injection.

Surface-based regional homogeneity in first-episode, drug-naïve major depression: a resting-state FMRI study.

BACKGROUND: Previous volume-based regional homogeneity (ReHo) studies neglected the intersubject variability in cortical folding patterns. Recently, surface-based ReHo was developed to reduce the intersubject variability and to increase statistical power. The present study used this novel surface-based ReHo approach to explore the brain functional activity differences between first-episode, drug-naïve MDD patients and healthy controls. METHODS: Thirty-three first-episode, drug-naïve MDD patients and 32 healthy controls participated in structural and resting-state fMRI scans. MDD patients were rated with a 17-item Hamilton Rating Scale for Depression prior to the scan. RESULTS: In comparison with the healthy controls, MDD patients showed reduced surface-based ReHo in the left insula. There was no increase in surface-based ReHo in MDD patients. The surface-based ReHo value in the left insula was not significantly correlated with the clinical information or the depressive scores in the MDD group. CONCLUSIONS: The decreased surface-based ReHo in the left insula in MDD may lead to the abnormal top-down cortical-limbic regulation of emotional and cognitive information. The surface-based ReHo may be a useful index to explore the pathophysiological mechanism of MDD.

Methylphenidate normalizes resting-state brain dysfunction in boys with attention deficit hyperactivity disorder.

We used resting-state functional magnetic resonance imaging (RS-fMRI) to investigate the acute effects of methylphenidate hydrochloride (MPH) on spontaneous brain activity in children with attention deficit hyperactivity disorder (ADHD). In all, 23 boys with ADHD were scanned twice, under either 10 mg dose of MPH or placebo, in a randomized, cross-over, counterbalanced placebo-controlled design. 32 Matched healthy controls were scanned once for comparison. Seven of the 23 ADHD boys participated in a follow-up 8-week MPH treatment. A regional homogeneity (ReHo) method was applied to characterize the local synchronization of spontaneous brain activity. ADHD boys under placebo compared with controls showed decreased ReHo in bilateral dorsolateral prefrontal cortices and increased ReHo in bilateral sensorimotor and parieto-visual cortices. Relative to placebo, MPH upregulated ReHo in bilateral ventral prefrontal cortices and cerebellar vermis, and downregulated ReHo in right parietal and visual areas that overlapped with the abnormally enhanced activities. When under MPH, ReHo differences between patients and controls were no longer observed. The preliminary prediction analysis revealed that the decreased ReHo in right parietal cortex after the acute MPH was positively correlated with the decreased symptom scores after the 8-week MPH treatment in the seven patients. We show that an acute dose of MPH normalized all fronto-parieto-cerebellar dysfunctions in boys with ADHD during the resting state. Preliminary findings furthermore suggest the potential of RS-fMRI as a prognostic imaging tool to identify response to MPH treatment.

Selectivity of N170 in the left hemisphere as an electrophysiological marker for expertise in reading Chinese.

OBJECTIVE: The left-lateralized N170, an event-related potential component consistently shown in response to alphabetic words, is a robust electrophysiological marker for reading expertise in an alphabetic language. In contrast, such a marker is lacking for expertise in reading Chinese, because the existing results about the lateralization of N170 for Chinese characters are mixed, reflecting complicated factors such as top-down modulation that contribute to the relative magnitudes of N170 in the left and right hemispheres. The present study aimed to explore a potential electrophysiological marker for reading expertise in Chinese with minimal top-down influence. METHODS: We recorded N170 responses to Chinese characters and three kinds of control stimuli in a content-irrelevant task, minimizing potential top-down effects. RESULTS: Direct comparison of the N170 amplitude in response to Chinese characters between the hemispheres showed a marginally significant left-lateralization effect. However, detailed analyses of N170 in each hemisphere revealed a more robust pattern of left-lateralization - the N170 in the left but not the right hemisphere differentiated Chinese characters from control stimuli. CONCLUSION: These results suggest that the selectivity of N170 (a greater N170 in response to Chinese characters than to control stimuli) within the left hemisphere rather than the hemispheric difference of N170 with regard to Chinese characters is an electrophysiological marker for expertise in reading Chinese.

Neonatal exposure to fluoxetine and fluvoxamine alteres spine density in mouse hippocampal CA1 pyramidal neurons.

Some women in childbearing ages take selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine and fluvoxamine for treating psychiatric symptoms. However, these compounds may cause some side effects to their children. It has been identified that early life exposure to SSRIs increased the chance of developing mood disorders and the biological basis is still unclear. Here, we studied the effects of neonatal exposure to SSRIs on neuronal morphology. We used GFP-transgenic mice to investigate the acute and long-lasting effects of early life exposure to SSRIs on dendritic spine density of CA1 neurons. We found that 18-day drug applications of fluoxetine and fluvoxamine significantly reduced spine density of basal dendrites at postnatal day 22 (P22), but only fluvoxamine caused a reduction of spine density of apical dendrites. Interestingly, compared with the control group, the spine densities of basal dendrites after fluoxetine and fluvoxamine exposure and the spine density of apical dendrites after fluoxetine exposure increased in adult mice at the age of P90. We also observed impaired locomotor activity in adult mice after exposure to SSRIs. Our findings demonstrated that neonatal exposure to SSRIs was capable of influencing the morphological plasticity of excitatory synapses. It raised the caution for clinical use of SSRIs.

Activation of extracellular signal-regulated kinase in the anterior cingulate cortex contributes to the induction of long-term potentiation in rats.

OBJECTIVE: To explore the role of the extracellular signal-regulated kinase (ERK)/cAMP response element binding protein (CREB) pathway in the induction of long-term potentiation (LTP) in the anterior cingulate cortex (ACC) that may be implicated in pain-related negative emotion. METHODS: LTP of field potential was recorded in ACC slice and the expressions of phospho-ERK (pERK) and phospho-CREB (pCREB) were examined using immunohistochemistry method. RESULTS: LTP could be induced stably in ACC slice by high frequency stimulation (2-train, 100 Hz, 1 s), while APv (an antagonist of NMDA receptor) could block the induction of LTP in the ACC, indicating that LTP in this experiment was NMDA receptor-dependent. Bath application of PD98059 (50 micromol/L), a selective MEK inhibitor, at 30 min before tetanic stimulation could completely block the induction of LTP. Moreover, the protein level of pERK in the ACC was transiently increased after LTP induction, starting at 5 min and returning to basal at 1 h after tetanic stimulation. The protein level of pCREB was also increased after LTP induction. The up-regulation in pERK and pCREB expressions could be blocked by pretreatment of PD98059. Double immunostaining showed that after LTP induction, most pERK was co-localized with pCREB. CONCLUSION: NMDA receptor and ERK-CREB pathway are necessary for the induction of LTP in rat ACC and may play important roles in pain emotion.

An optimized recording method to characterize biophysical and pharmacological properties of acid-sensing ion channel.

OBJECTIVE: To re-confirm and characterize the biophysical and pharmacological properties of endogenously expressed human acid-sensing ion channel 1a (hASIC1a) current in HEK293 cells with a modified perfusion methods. METHODS: With cell floating method, which is separating the cultured cell from coverslip and putting the cell in front of perfusion tubing, whole cell patch clamp technique was used to record hASIC1a currents evoked by low pH external solution. RESULTS: Using cell floating method, the amplitude of hASIC1a currents activated by pH 5.0 in HEK293 cells is twice as large as that by the conventional method where the cells remain attached to coverslip. The time to reach peak at two different recording conditions is (21+/-5) ms and (270+/-25) ms, respectively. Inactivation time constants are (496+/-23) ms and (2284+/-120) ms, respectively. The cell floating method significantly increases the amiloride potency of block on hASIC1a [IC50 is (3.4+/-1.1) micromol/L and (2.4+/- 0.9) micromol/L, respectively]. Both recording methods have similar pH activation EC50 (6.6+/-0.6, 6.6+/-0.7, respectively). CONCLUSION: ASICs channel activation requires fast exchange of extracellular solution with the different pH values. With cell floating method, the presence of hASIC1a current was re-confirmed and the biophysical and pharmacological properties of hASIC1a channel in HEK293 cells were precisely characterized. This method could be used to study all ASICs and other ligand-gated channels that require fast extracellular solution exchange.