Separate optogenetic manipulation of Nerve/glial antigen 2 (NG2) glia and mural cells using the NG2 promoter.

Nerve/glial antigen 2 (NG2) is a protein marker of NG2 glia and mural cells, and NG2 promoter activity is utilized to target these cells. However, the NG2 promoter cannot target NG2 glia and mural cells separately. This has been an obstacle for NG2 glia-specific manipulation. Here, we developed transgenic mice in which either cell type can be targeted using the NG2 promoter. We selected a tetracycline-controllable gene induction system for cell type-specific transgene expression, and generated NG2-tetracycline transactivator (tTA) transgenic lines. We crossed tTA lines with the tetO-ChR2 (channelrhodopsin-2)-EYFP line to characterize tTA-dependent transgene induction. We isolated two unique NG2-tTA mouse lines: one that induced ChR2-EYFP only in mural cells, likely due to the chromosomal position effect of NG2-tTA insertion, and the other that induced it in both cell types. We then applied a Cre-mediated set-subtraction strategy to the latter case and eliminated ChR2-EYFP from mural cells, resulting in NG2 glia-specific transgene induction. We further demonstrated that tTA-dependent ChR2 expression could manipulate cell function. Optogenetic mural cell activation decreased cerebral blood flow, as previously reported, indicating that tTA-mediated ChR2 expression was sufficient to impact cellular function. ChR2-mediated depolarization was observed in NG2 glia in acute hippocampal slices. In addition, ChR2-mediated depolarization of NG2 glia inhibited their proliferation but promoted their differentiation in juvenile mice. Since the tTA-tetO combination is expandable, the mural cell-specific NG2-tTA line and the NG2 glia-specific NG2-tTA line will permit us to conduct observational and manipulation studies to examine in vivo function of these cells separately.

Synaptic plasticity in hippocampal CA1 neurons of mice lacking inositol-1,4,5-trisphosphate receptor-binding protein released with IP3 (IRBIT).

In hippocampal CA1 neurons of wild-type mice, a short tetanus (15 or 20 pulses at 100 Hz) or a standard tetanus (100 pulses at 100 Hz) to a naive input pathway induces long-term potentiation (LTP) of the responses. Low-frequency stimulation (LFS; 1000 pulses at 1 Hz) 60 min after the standard tetanus reverses LTP (depotentiation [DP]), while LFS applied 60 min prior to the standard tetanus suppresses LTP induction (LTP suppression). We investigated LTP, DP, and LTP suppression of both field excitatory postsynaptic potentials and population spikes in CA1 neurons of mice lacking the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R)-binding protein released with IP3 (IRBIT). The mean magnitudes of LTP induced by short and standard tetanus were not different in mutant and wild-type mice. In contrast, DP and LTP suppression were attenuated in mutant mice, whereby the mean magnitude of responses after LFS or tetanus were significantly greater than in wild-type mice. These results suggest that, in hippocampal CA1 neurons, IRBIT is involved in DP and LTP suppression, but is not essential for LTP. The attenuation of DP and LTP suppression in mice lacking IRBIT indicates that this protein, released during or after priming stimulations, determines the direction of LTP expression after the delivery of subsequent stimulations.

Depotentiation depends on IP3 receptor activation sustained by synaptic inputs after LTP induction.

In CA1 neurons of guinea pig hippocampal slices, long-term potentiation (LTP) was induced in field excitatory postsynaptic potentials (EPSPs) or population spikes (PSs) by the delivery of high-frequency stimulation (HFS, 100 pulses at 100 Hz) to CA1 synapses, and was reversed by the delivery of a train of low-frequency stimulation (LFS, 1000 pulses at 2 Hz) at 30 min after HFS (depotentiation), and this effect was inhibited when test synaptic stimulation was halted for a 19-min period after HFS or for a 20-min period after LFS or applied over the same time period in the presence of an antagonist of N-methyl-D-aspartate receptors (NMDARs), group I metabotropic glutamate receptors (mGluRs), or inositol 1, 4, 5-trisphosphate receptors (IP3Rs). Depotentiation was also blocked by the application of a Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor or a calcineurin inhibitor applied in the presence of test synaptic input for a 10-min period after HFS or for a 20-min period after LFS. These results suggest that, in postsynaptic neurons, the coactivation of NMDARs and group I mGluRs due to sustained synaptic activity following LTP induction results in the activation of IP3Rs and CaMKII, which leads to the activation of calcineurin after LFS and depotentiation of CA1 synaptic responses.

[Development and testing of reliability and validity of a subjective QOL scale for older adults perceiving a dynamic healthy life through the three dimensions of biological life, everyday life, and overall course of life].

Objectives　To develop and assess the reliability and validity of a scale measuring subjective quality of life (QOL), which encompasses the "strength and ability" to live positively through the three dimensions of biological life, everyday life, and overall course of life, in order to support QOL in older adults.Methods　We reviewed related literature and conducted interviews with patients with chronic diseases. Participants rated their QOL on a seven-point scale using the visual analog scale. Interviewer-administered questionnaires were used to collect data from 100 older adults living in their own homes. The participants were between the ages of 70 and 84, and were recruited from comprehensive community support centers or from among hospital outpatients. We assessed scale reliability using Cronbach's α, item-total (I-T) correlation analysis, and calculation of α coefficient-if-item-deleted. We examined content validity by analyzing the content of the free response items. To evaluate construct validity, we carried out a hierarchical multiple regression analysis, examined the semantic content of the factors related to subjective QOL, and confirmed consistency with previous studies.Results　Regarding the reliability analysis of the scale, the α coefficient was 0.898, and both the I-T correlation and α coefficient-if-item-deleted exceeded the minimum value considered reliable. In examining content validity, the categories extracted for each of the three dimensions were found to demonstrate the characteristics of the general ideas of each dimension of QOL. Thus, the scale was confirmed to have overall content validity. As for the assessment of validity of its constitutive concepts, subjective QOL scores were significantly high among participants who had jobs, had role-related or financial capacity, used two or more nursing services, or scored high in perceived health competence, social networking, and sense of coherence (SOC). In addition, "meaningfulness" of SOC, and financial capacity had significant correlations with subjective QOL. These results are consistent with past research and therefore confirm construct validity.Conclusion　This study sufficiently confirmed the reliability and validity of the scale, and consequently its usability.

Region- and Cell Type-Specific Facilitation of Synaptic Function at Destination Synapses Induced by Oligodendrocyte Depolarization.

The axonal conduction of action potentials affects the absolute time it takes to transmit nerve impulses as well as temporal summation at destination synapses. At the physiological level, oligodendrocyte depolarization facilitates axonal conduction along myelinated fibers in the hippocampus; however, the functional significance of this facilitation is largely unknown. In this study, we examined the physiology of the facilitation of axonal conduction by investigating the changes in synaptic responses at destination synapses using male and female mice in which channelrhodopsin-2 expression was restricted to oligodendrocytes. The subiculum, one of the projection areas of the examined axons at the alveus of the hippocampus, is divided into three regions (proximal, mid, and distal) and contains two types of principal neurons: regular firing and bursting pyramidal cells. We found a significant increase in excitatory synaptic responses following optogenetic oligodendrocyte depolarization in bursting neurons at two of the three regions, but not in regular firing neurons at any region. The long-term potentiation (LTP) induced by theta burst stimulation at the synapses showing a significant increase was also enhanced after oligodendrocyte depolarization. Conversely, the reduction of oligodendrocyte depolarization during theta burst stimulation, which was achieved by photostimulation of archaerhodopsin-T expressed selectively on oligodendrocytes, reduced the magnitude of LTP. These results show that oligodendrocyte depolarization contributes to the fine control of synaptic activity between the axons they myelinate and targets subicular cells in a region- and cell type-specific manner, and suggest that oligodendrocyte depolarization during conditioning of stimuli is involved in the induction of LTP.SIGNIFICANCE STATEMENT All activity in the nervous system depends on the propagation of action potentials. Changes in the axonal conduction of action potentials influence the timing of synaptic transmission and information processing in neural circuits. At the physiological level, oligodendrocyte depolarization facilitates axonal conduction along myelinated fibers. In this study, we investigated the functional significance of the facilitation of axonal conduction induced by physiological oligodendrocyte depolarization. Using optogenetics and electrophysiological recordings, we demonstrated that oligodendrocyte depolarization in mice expressing channelrhodopsin-2 on oligodendrocytes increased excitatory synaptic responses and enhanced the induction of long-term potentiation at destination synapses in a region- and cell type-specific manner. This facilitation may have a hitherto unappreciated influence on the transfer of information between regions in the nervous system.

Oligodendrocyte Physiology Modulating Axonal Excitability and Nerve Conduction.

Oligodendrocytes enable saltatory conduction by forming a myelin sheath around axons, dramatically boosts action potential conduction velocity. In addition to this canonical function of oligodendrocytes, it is now known that oligodendrocytes can respond to neuronal activity and regulate axonal conduction. Importantly, white matter plasticity, including adaptive responses by oligodendrocytes, has been shown to be involved in learning and memory. In this chapter, the role of oligodendrocytes in axonal conduction and axonal excitability will be reviewed. Focus will be paid to the mechanisms through which oligodendrocytes, including perineuronal oligodendrocytes, facilitate and suppress axonal conduction.

Having another child without intellectual disabilities: Comparing mothers of a single child with disability and mothers of multiple children with and without disability.

To investigate how having a child without a disability is related to maternal mental health and its predictors, we compared mothers of a single child with intellectual disabilities (single-child group, n = 117) and mothers of children with and without intellectual disabilities (multiple-children group, n = 457), in Japan. Compared to the multiple-children group, the single-child group had lower hope and social capital and poorer mental health; furthermore, 42.5% of them had decided not to have another child, despite desiring one. Hope was the strongest predictor of mental health in both groups but was more positively related to mental health in the multiple-children group. The fear of the possibility of the next child having a disability and receiving inadequate support were the obstacles for mothers who had decided not to have another child. Thus, greater support and more opportunities for obtaining adequate information about the implications of having another child may be needed.

Ectopic positioning of Bergmann glia and impaired cerebellar wiring in Mlc1-over-expressing mice.

Mlc1 is a causative gene for megalencephalic leukoencephalopathy with subcortical cysts, and is expressed in astrocytes. Mlc1-over-expressing mice represent an animal model of early-onset leukoencephalopathy, which manifests as astrocytic swelling followed by myelin membrane splitting in the white matter. It has been previously reported that Mlc1 is highly expressed in Bergmann glia, while the cerebellar phenotypes of Mlc1-over-expressing mouse have not been characterized. Here, we examined the cerebellum of Mlc1-over-expressing mouse and found that the distribution of Bergmann glia (BG) was normally compacted along the Purkinje cell (PC) layer until postnatal day 10 (P10), while most BG were dispersed throughout the molecular layer by P28. Ectopic BG were poorly wrapped around somatodendritic elements of PCs and exhibited reduced expression of the glutamate transporter glutamate-aspartate transporter. Extraordinarily slow and small climbing fiber (CF)-mediated excitatory post-synaptic currents, which are known to be elicited under accelerated glutamate spillover, emerged at P20-P28 when BG ectopia was severe, but not at P9-P12 when ectopia was mild. Furthermore, maturation of CF wiring, which translocates the site of innervation from somata to proximal dendrites, was also impaired. Manipulations that restricted the Mlc1-over-expressing period successfully generated mice with and without BG ectopia, depending on the over-expressing period. Together, these findings suggest that there is a critical time window for mechanisms that promote the positioning of BG in the PC layer. Once normal positioning of BG is affected, the differentiation of BG is impaired, leading to insufficient glial wrapping, exacerbated glutamate spillover, and aberrant synaptic wiring in PCs. Open Practices Open Science: This manuscript was awarded with the Open Materials Badge. For more information see: https://cos.io/our-services/open-science-badges/ Cover Image for this issue: doi: 10.1111/jnc.14199.

Modulatory Effects of Perineuronal Oligodendrocytes on Neuronal Activity in the Rat Hippocampus.

Action potentials are fundamental to relaying information from region to region in the nervous system. Changes in action potential firing patterns in neural circuits influence how the brain processes information. In our previous study, we focused on interneuron/perineuronal astrocyte pairs in the hippocampal CA1 region and reported that direct depolarization of perineuronal astrocytes modulated the firing pattern of interneurons. In the current study, we investigated the morphological and electrophysiological properties of perineuronal oligodendrocytes, and examined their modulatory effects on interneuronal firing in the CA1 region. Perineuronal oligodendrocytes only had a few processes, which were crooked, intricately twisted, and twined around the soma and proximal region of the main processes of adjacent interneurons. Whole-cell current patterns of perineuronal oligodendrocytes were homogenous and the current-voltage relationship showed remarkable outward rectification. Although the K+ channel blockers, tetraethylammonium and 4-aminopyridine, clearly blocked outward currents, Ba2+ did not significantly alter whole-cell currents. Unlike perineuronal astrocytes, the depolarization of perineuronal oligodendrocytes had no effect on interneuronal firing; however, when the interneurons were firing at a higher frequency, the hyperpolarization of perineuronal oligodendrocytes suppressed their action potentials. The suppressive effects of perineuronal oligodendrocytes were inhibited in the presence of a low concentration of tetraethylammonium, which selectively blocked deep and fast afterhyperpolarization. These results suggest that perineuronal oligodendrocytes suppress interneuronal firing through their influence on K+ channels, which are responsible for deep and fast afterhyperpolarization.

Reliability and validity of a 12-item medication adherence scale for patients with chronic disease in Japan.

BACKGROUND: To improve and support medication adherence among patients with chronic diseases, especially for long-term medication, it is important to consider both their relationship with healthcare providers and their lifestyle. We tested the reliability and validity of a modified 12-item Medication Adherence Scale. METHODS: We revised a 14-item measure of medication adherence, created in 2009, to a more concise and clear 12-item version, and we verified the reliability and validity of the 12-item scale. We included 328 patients with chronic diseases participating in the Chronic Disease Self-Management Program in Japan from 2011 to 2014. Confirmatory factor analysis was used to assess whether the four factors assessed were the same as the previous 14-item Medication Adherence Scale. Cronbach's coefficient alpha was used to assess internal consistency reliability, and the relationships between patient demographic characteristics and medication adherence were compared with previous studies. RESULTS: The 12 items were categorized into the four factors "medication compliance", "collaboration with healthcare providers", "willingness to access and use information about medication", and "acceptance to take medication and how taking medication fits patient's lifestyle". Confirmatory factor analysis showed χ2/df = 2.6, CFI = 0.94, and RMSEA = 0.069. Cronbach's alpha for the 12-item scale was 0.78. Cronbach's alpha for the four subscales was 0.74, 0.81, 0.67, and 0.45. Higher medication adherence was significantly associated with being a female patient, living with someone else, and age 40-49 years versus age 20-29 years. These relationships were the same as in previous studies. CONCLUSIONS: We modified our original 14-item scale to a 12-item Medication Adherence Scale for patients with chronic diseases, which considers their relationship with healthcare providers and lifestyle. Refinement might be needed because of the relatively low reliability of subscales. However, the modified scale is expected to contribute to more effective self-management of medication and to improving medication adherence, particularly among patients with chronic diseases who require long-term medication not only in Japan but also in other countries.

Nicotinic and muscarinic agonists and acetylcholinesterase inhibitors stimulate a common pathway to enhance GluN2B-NMDAR responses.

Nicotinic and muscarinic ACh receptor agonists and acetylcholinesterase inhibitors (AChEIs) can enhance cognitive function. However, it is unknown whether a common signaling pathway is involved in the effect. Here, we show that in vivo administration of nicotine, AChEIs, and an m1 muscarinic (m1) agonist increase glutamate receptor, ionotropic, N-methyl D-aspartate 2B (GluN2B)-containing NMDA receptor (NR2B-NMDAR) responses, a necessary component in memory formation, in hippocampal CA1 pyramidal cells, and that coadministration of the m1 antagonist pirenzepine prevents the effect of cholinergic drugs. These observations suggest that the effect of nicotine is secondary to increased release of ACh via the activation of nicotinic ACh receptors (nAChRs) and involves m1 receptor activation through ACh. In vitro activation of m1 receptors causes the selective enhancement of NR2B-NMDAR responses in CA1 pyramidal cells, and in vivo exposure to cholinergic drugs occludes the in vitro effect. Furthermore, in vivo exposure to cholinergic drugs suppresses the potentiating effect of Src on NMDAR responses in vitro. These results suggest that exposure to cholinergic drugs maximally stimulates the m1/guanine nucleotide-binding protein subunit alpha q/PKC/proline-rich tyrosine kinase 2/Src signaling pathway for the potentiation of NMDAR responses in vivo, occluding the in vitro effects of m1 activation and Src. Thus, our results indicate not only that nAChRs, ACh, and m1 receptors are on the same pathway involving Src signaling but also that NR2B-NMDARs are a point of convergence of cholinergic and glutamatergic pathways involved in learning and memory.

Prior activation of inositol 1,4,5-trisphosphate receptors suppresses the subsequent induction of long-term potentiation in hippocampal CA1 neurons.

We investigated the role of inositol 1,4,5-trisphosphate receptors (IP3Rs) activated by preconditioning low-frequency afferent stimulation (LFS) in the subsequent induction of long-term potentiation (LTP) in CA1 neurons in hippocampal slices from mature guinea pigs. Induction of LTP in the field excitatory postsynaptic potential or the population spike by the delivery of high-frequency stimulation (HFS, a tetanus of 100 pulses at 100 Hz) to the Schaffer collateral-commissural pathway to CA1 neuron synapses was suppressed when group I metabotropic glutamate receptors (mGluRs) were activated prior to the delivery of HFS. LTP induction was also suppressed when CA1 synapses were preconditioned 60 min before HFS by LFS of 1000 pulses at 1 Hz and this effect was inhibited when the test stimulation delivered at 0.05 Hz was either halted or applied in the presence of an antagonist ofN-methyl-d-aspartate receptors, group I mGluRs, or IP3Rs during a 20-min period from 20 to 40 min after the end of LFS. Furthermore, blockade of group I mGluRs or IP3Rs immediately before the delivery of HFS overcame the effects of the preconditioning LFS on LTP induction. These results suggest that, in CA1 neurons, after a preconditioning LFS, activation of group I mGluRs caused by the test stimulation results in IP3Rs activation that leads to a failure of LTP induction.

Physical Punishment, Mental Health and Sense of Coherence Among Parents of Children with Intellectual Disability in Japan.

BACKGROUND: Although sense of coherence (SOC) moderates parental stress, the relationship between SOC, parental mental health and physical punishment of children with intellectual disabilities remains uncertain. The present authors describe parental physical punishment towards children with intellectual disabilities and investigate its related demographic characteristics, SOC and parental mental health. MATERIALS AND METHODS: With the cooperation of Tokyo's 10 special needs schools, the present authors obtained 648 questionnaire responses from parents of children with intellectual disabilities. RESULTS: Of the parents, 69.7% reported having physically punished their children with intellectual disabilities. This was positively associated with parents' younger age, poorer mental health, lower SOC, children's younger age, birth order (firstborns) and disability type (autism/pervasive developmental disorder). CONCLUSIONS: This is the first study supporting the relationship between SOC, mental health and physical punishment use among parents of children with intellectual disabilities. It may assist the development of strategies to prevent physical abuse of children with disabilities.

Activity-dependent modulation of the axonal conduction of action potentials along rat hippocampal mossy fibers.

The axonal conduction of action potentials in the nervous system is generally considered to be a stable signal for the relaying of information, and its dysfunction is involved in impairment of cognitive function. Recent evidence suggests that the conduction properties and excitability of axons are more variable than traditionally thought. To investigate possible changes in the conduction of action potentials along axons in the central nervous system, we recorded action potentials from granule cells that were evoked and conducted antidromically along unmyelinated mossy fibers in the rat hippocampus. To evaluate changes in axons by eliminating any involvement of changes in the somata, two latency values were obtained by stimulating at two different positions and the latency difference between the action potentials was measured. A conditioning electrical stimulus of 20 pulses at 1 Hz increased the latency difference and this effect, which lasted for approximately 30 s, was inhibited by the application of an α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)/kainate receptor antagonist or a GluK1-containing kainate receptor antagonist, but not by an AMPA receptor-selective antagonist or an N-methyl-d-aspartate receptor antagonist. These results indicated that axonal conduction in mossy fibers is modulated in an activity-dependent manner through the activation of GluK1-containing kainate receptors. These dynamic changes in axonal conduction may contribute to the physiology and pathophysiology of the brain.

[Nationally representative score of the Japanese language version of the 13-item 7-point sense of coherence scale].

OBJECTIVES: The amount of research relating to evaluation of intervention programs with regard to sense of coherence, a concept of salutogenic stressor coping capacity, is increasing in Japan. However, a nationally representative score of the Japanese version of the sense of coherence scale has not yet been reported. The aim of this study was to describe the 13-item, 7-point Japanese sense of coherence scale (SOC-13), with scoring by sex and age group, and to examine the relationships between the score and locality and city size. METHODS: Four thousand Japanese men and women were selected by stratified random sampling, and a cross-sectional, self-administered questionnaire survey was conducted using the placement method. Responses were obtained from 2,067 individuals (response rate: 51.7%). This study analyzed 956 men and 1,107 women (mean age [standard deviation]: 50.0 [14.3]). RESULTS: The mean score on the SOC-13 was 59.0 (12.2) in all participants, 59.1 (11.8) in men, and 58.9 (12.5) in women. No significant difference was found between men and women (P=0.784). ANOVA and multiple comparison for age difference showed a clear relationship (P<0.05) between higher age and a higher SOC-13 score. Moreover, the results of main and interaction effects in ANCOVA, with independent variables for locality (11 segments) and city size (four segments), were not significant when controlled for age. CONCLUSION: A nationally representative score for the Japanese SOC-13 was acquired. In future research, application of the SOC-13 in Japan for clinical studies is anticipated based on the nationally representative score.

Short- and long-term functional plasticity of white matter induced by oligodendrocyte depolarization in the hippocampus.

Plastic changes in white matter have received considerable attention in relation to normal cognitive function and learning. Oligodendrocytes and myelin, which constitute the white matter in the central nervous system, can respond to neuronal activity with prolonged depolarization of membrane potential and/or an increase in the intracellular Ca(2+) concentration. Depolarization of oligodendrocytes increases the conduction velocity of an action potential along axons myelinated by the depolarized oligodendrocytes, indicating that white matter shows functional plasticity, as well as structural plasticity. However, the properties and mechanism of oligodendrocyte depolarization-induced functional plastic changes in white matter are largely unknown. Here, we investigated the functional plasticity of white matter in the hippocampus using mice with oligodendrocytes expressing channelrhodopsin-2. Using extracellular recordings of compound action potentials at the alveus of the hippocampus, we demonstrated that light-evoked depolarization of oligodendrocytes induced early- and late-onset facilitation of axonal conduction that was dependent on the magnitude of oligodendrocyte depolarization; the former lasted for approximately 10 min, whereas the latter continued for up to 3 h. Using whole-cell recordings from CA1 pyramidal cells and recordings of antidromic action potentials, we found that the early-onset short-lasting component included the synchronization of action potentials. Moreover, pharmacological analysis demonstrated that the activation of Ba(2+) -sensitive K(+) channels was involved in early- and late-onset facilitation, whereas 4-aminopyridine-sensitive K(+) channels were only involved in the early-onset component. These results demonstrate that oligodendrocyte depolarization induces short- and long-term functional plastic changes in the white matter of the hippocampus and plays active roles in brain functions.

Mental health of patients with human immunodeficiency virus in Japan: a comparative analysis of employed and unemployed patients.

In developed countries, human immunodeficiency virus (HIV) has become a chronic disease. The aims of this study were to clarify the physical, social, and psychological factors affecting Japanese HIV patients in a stable condition and to identify factors related to mental health of employed and unemployed HIV patients. The target subjects were people with HIV infection who were treated as outpatients at core hospitals for acquired immune deficiency syndrome (AIDS) treatment in Japan. A questionnaire including items from the Hospital Anxiety and Depression Scale (HADS) was sent to each medical facility with a request for participation from the HIV-infected outpatients. Responses from 1199 patients were analyzed. Mental health was reportedly better in the employed patients than in the unemployed patients. The unemployed patients were more likely to have resigned from their jobs because of poor health, to have resigned voluntarily, or to have been unfairly dismissed. Once the patients stopped working because of HIV, returning to work became difficult. In the employed patients, a good workplace environment was strongly related to lower scores on HADS. Higher HADS scores were recorded for employed patients infected with HIV for six years or more. For the unemployed patients, a relationship was observed between strong feelings of stigmatization and HADS scores. Quitting a job because of an experience related to HIV status may be related to feelings of stigmatization.

Increased astrocytic ATP release results in enhanced excitability of the hippocampus.

Astrocytes, a major subtype of glia, interact with neurons as a supportive partner supplying energy sources and growth factors. Astrocytes regulate the activity of neighboring neurons by releasing chemical transmitters (gliotransmitters). However, the precise role of gilotransmitters in regulating neuronal activity is still under debate. Here, we report that a subtle enhancement in the release of one gliotransmitter, ATP, affects synaptic potentiation from an analysis of mice containing an astrocyte-selective (GFAP) mutation. We found that, relative to normal mice, weaker stimulation induced long-term potentiation (LTP) in mutant mice, indicating that the threshold to induce LTP was lowered in the mutant. While excitatory transmission was normal in the mutant, inhibitory GABAergic transmission was suppressed. We found that a low concentration of adenosine selectively attenuated inhibitory neuronal activity and lowered the threshold to induce LTP in wild type mice. In comparison, adenosine A(1) receptor antagonism reversed the lowered LTP threshold back to normal in the mutant mouse. We verified that adenosine levels in the cerebrospinal fluid of mutant mice were slightly elevated compared to wild type mice. This was apparently caused by an increase in ATP release from mutant astrocytes that could provide a source of augmented adenosine levels in the mutant. ATP is thought to suppress the excitability of neuronal circuits; however, a small increase in ATP release can result in a suppressed inhibitory tone and enhanced excitability of neuronal circuitry. These findings demonstrate that ATP released from astrocytes acts in a bidirectional fashion to regulate neuronal excitability depending on concentration.

Illness experience of adults with cervical spinal cord injury in Japan: a qualitative investigation.

BACKGROUND: There is growing recognition that healthcare policy should be guided by the illness experience from a layperson's or insider's perspective. One such area for exploration would include patient-centered research on traumatic Spinal Cord Injury (SCI), a condition associated with permanent physical disability requiring long-term and often complex health care. The chronicity of SCI can, in turn, affect individuals' sense of self. Although previous research in Western countries suggests that people with SCI find a way to cope with their disability through social participation and family bonds, the process of adjustment among people with cervical SCI (CSCI) living in Japan may be different because of the restrained conditions of their social participation and the excessive burden on family caregivers. The purpose of this study was to examine the impact of injury and the process of accommodation in people with CSCI in Japan. METHODS: Semi-structured home interviews were conducted with 29 participants who were recruited from a home-visit nursing care provider and three self-help groups. Interviews were recorded, transcribed and analyzed based on the grounded theory approach. RESULTS: Five core categories emerged from the interview data: being at a loss, discrediting self by self and others, taking time in performance, restoring competency, and transcending limitations of disability. Overall, the process by which participants adjusted to and found positive meaning in their lives involved a continuous search for comfortable relationships between self, disability and society. CONCLUSIONS: The results of this study suggest that persons with CSCI do not merely have disrupted lives, but find positive meaning through meaningful interactions. Family members added to the discredit of self by making the injured person entirely dependent on them. Gaining independence from family members was the key to restoring competency in people with CSCI. At the same time, social participation was pursued for transcending the limitations of disability. The results also imply that social issues affect how people interpret their disability. These findings suggest that public health policy makers should recognize the need to enhance independence in people with disability as well as change the social assumptions about their care.