Cav3 T-Type Voltage-Gated Ca2+ Channels and the Amyloidogenic Environment: Pathophysiology and Implications on Pharmacotherapy and Pharmacovigilance.

Voltage-gated Ca2+ channels (VGCCs) were reported to play a crucial role in neurotransmitter release, dendritic resonance phenomena and integration, and the regulation of gene expression. In the septohippocampal system, high- and low-voltage-activated (HVA, LVA) Ca2+ channels were shown to be involved in theta genesis, learning, and memory processes. In particular, HVA Cav2.3 R-type and LVA Cav3 T-type Ca2+ channels are expressed in the medial septum-diagonal band of Broca (MS-DBB), hippocampal interneurons, and pyramidal cells, and ablation of both channels was proven to severely modulate theta activity. Importantly, Cav3 Ca2+ channels contribute to rebound burst firing in septal interneurons. Consequently, functional impairment of T-type Ca2+ channels, e.g., in null mutant mouse models, caused tonic disinhibition of the septohippocampal pathway and subsequent enhancement of hippocampal theta activity. In addition, impairment of GABA A/B receptor transcription, trafficking, and membrane translocation was observed within the septohippocampal system. Given the recent findings that amyloid precursor protein (APP) forms complexes with GABA B receptors (GBRs), it is hypothesized that T-type Ca2+ current reduction, decrease in GABA receptors, and APP destabilization generate complex functional interdependence that can constitute a sophisticated proamyloidogenic environment, which could be of potential relevance in the etiopathogenesis of Alzheimer's disease (AD). The age-related downregulation of T-type Ca2+ channels in humans goes together with increased Aß levels that could further inhibit T-type channels and aggravate the proamyloidogenic environment. The mechanistic model presented here sheds new light on recent reports about the potential risks of T-type Ca2+ channel blockers (CCBs) in dementia, as observed upon antiepileptic drug application in the elderly.

Epigenetic alterations in longevity regulators, reduced life span, and exacerbated aging-related pathology in old father offspring mice.

Advanced age is not only a major risk factor for a range of disorders within an aging individual but may also enhance susceptibility for disease in the next generation. In humans, advanced paternal age has been associated with increased risk for a number of diseases. Experiments in rodent models have provided initial evidence that paternal age can influence behavioral traits in offspring animals, but the overall scope and extent of paternal age effects on health and disease across the life span remain underexplored. Here, we report that old father offspring mice showed a reduced life span and an exacerbated development of aging traits compared with young father offspring mice. Genome-wide epigenetic analyses of sperm from aging males and old father offspring tissue identified differentially methylated promoters, enriched for genes involved in the regulation of evolutionarily conserved longevity pathways. Gene expression analyses, biochemical experiments, and functional studies revealed evidence for an overactive mTORC1 signaling pathway in old father offspring mice. Pharmacological mTOR inhibition during the course of normal aging ameliorated many of the aging traits that were exacerbated in old father offspring mice. These findings raise the possibility that inherited alterations in longevity pathways contribute to intergenerational effects of aging in old father offspring mice.

Pharmacological Neuroenhancement: Current Aspects of Categorization, Epidemiology, Pharmacology, Drug Development, Ethics, and Future Perspectives.

Recent pharmacoepidemiologic studies suggest that pharmacological neuroenhancement (pNE) and mood enhancement are globally expanding phenomena with distinctly different regional characteristics. Sociocultural and regulatory aspects, as well as health policies, play a central role in addition to medical care and prescription practices. The users mainly display self-involved motivations related to cognitive enhancement, emotional stability, and adaptivity. Natural stimulants, as well as drugs, represent substance abuse groups. The latter comprise purines, methylxanthines, phenylethylamines, modafinil, nootropics, antidepressants but also benzodiazepines, ß-adrenoceptor antagonists, and cannabis. Predominant pharmacodynamic target structures of these substances are the noradrenergic/dopaminergic and cholinergic receptor/transporter systems. Further targets comprise adenosine, serotonin, and glutamate receptors. Meta-analyses of randomized-controlled studies in healthy individuals show no or very limited verifiability of positive effects of pNE on attention, vigilance, learning, and memory. Only some members of the substance abuse groups, i.e., phenylethylamines and modafinil, display positive effects on attention and vigilance that are comparable to caffeinated drinks. However, the development of new antidementia drugs will increase the availability and the potential abuse of pNE. Social education, restrictive regulatory measures, and consistent medical prescription practices are essential to restrict the phenomenon of neuroenhancement with its social, medical, and ethical implications. This review provides a comprehensive overview of the highly dynamic field of pharmacological neuroenhancement and elaborates the dramatic challenges for the medical, sociocultural, and ethical fundaments of society.

Functional implications of Cav 2.3 R-type voltage-gated calcium channels in the murine auditory system - novel vistas from brainstem-evoked response audiometry.

Voltage-gated Ca2+ channels (VGCCs) are considered to play a key role in auditory perception and information processing within the murine inner ear and brainstem. In the past, Cav 1.3 L-type VGCCs gathered most attention as their ablation causes congenital deafness. However, isolated patch-clamp investigation and localization studies repetitively suggested that Cav 2.3 R-type VGCCs are also expressed in the cochlea and further components of the ascending auditory tract, pointing to a potential functional role of Cav 2.3 in hearing physiology. Thus, we performed auditory profiling of Cav 2.3+/+ controls, heterozygous Cav 2.3+/- mice and Cav 2.3 null mutants (Cav 2.3-/- ) using brainstem-evoked response audiometry. Interestingly, click-evoked auditory brainstem responses (ABRs) revealed increased hearing thresholds in Cav 2.3+/- mice from both genders, whereas no alterations were observed in Cav 2.3-/- mice. Similar observations were made for tone burst-related ABRs in both genders. However, Cav 2.3 ablation seemed to prevent mutant mice from total hearing loss particularly in the higher frequency range (36-42 kHz). Amplitude growth function analysis revealed, i.a., significant reduction in ABR wave WI and WIII amplitude in mutant animals. In addition, alterations in WI -WIV interwave interval were observed in female Cav 2.3+/- mice whereas absolute latencies remained unchanged. In summary, our results demonstrate that Cav 2.3 VGCCs are mandatory for physiological auditory information processing in the ascending auditory tract.

Neuroenhancement and mood enhancement ­ Physiological and pharmacodynamical background. / Hirndoping ­ Neuroenhancement Pharmakodynamik des Neuroenhancement und physiologische Grundlagen.

Pharmacological neuroenhancement and mood enhancement are gaining tremendous importance in society. The main motivation for neuroenhancement and mood enhancement is the anticipated increase in attention and vigilance, better performance in learning and memory and mood stability to meet the complex demands of an exacerbating meritocracy. Most users apply drugs originally designated for attention disorders, sleep disorders or dementia. Application of related drugs in terms of enhancement strategies in healthy individuals is off-label per se, the acquisition and distribution illegal. Here, we first provide an overview of the basic physiological mechanisms underlying vigilance, learning and memory, and emotional states. We then present the different pharmacological classes, i. a. purines and methylxanthines, phenylethylamine, modafinil, nootropics and antidepressants and elaborate their pharmacodynamics profile. Special attention will be paid to the norepinephrine/dopamine and cholinergic receptors and transporter systems but also to functional interaction with adenosine, serotonine and the glutamate receptor systems. Metaanalysis revealed that efficacy reported in, e. g. ADHD or dementia patients cannot be translated to healthy individuals. A validated positive effect on attention and vigilance has only been reported for some phenylethylamines and modafinil. It is likely that new developments, particularly in the field of antidementives will dramatically enhance neuroenhancement and mood enhancement. Drug regulatory actions, public and political discussions are necessary to meet the ethical and legal challenges of neuroenhancement and mood enhancement in the future.

Gender-Specific Hippocampal Dysrhythmia and Aberrant Hippocampal and Cortical Excitability in the APPswePS1dE9 Model of Alzheimer's Disease.

Alzheimer's disease (AD) is a multifactorial disorder leading to progressive memory loss and eventually death. In this study an APPswePS1dE9 AD mouse model has been analyzed using implantable video-EEG radiotelemetry to perform long-term EEG recordings from the primary motor cortex M1 and the hippocampal CA1 region in both genders. Besides motor activity, EEG recordings were analyzed for electroencephalographic seizure activity and frequency characteristics using a Fast Fourier Transformation (FFT) based approach. Automatic seizure detection revealed severe electroencephalographic seizure activity in both M1 and CA1 deflection in APPswePS1dE9 mice with gender-specific characteristics. Frequency analysis of both surface and deep EEG recordings elicited complex age, gender, and activity dependent alterations in the theta and gamma range. Females displayed an antithetic decrease in theta (θ) and increase in gamma (γ) power at 18-19 weeks of age whereas related changes in males occurred earlier at 14 weeks of age. In females, theta (θ) and gamma (γ) power alterations predominated in the inactive state suggesting a reduction in atropine-sensitive type II theta in APPswePS1dE9 animals. Gender-specific central dysrhythmia and network alterations in APPswePS1dE9 point to a functional role in behavioral and cognitive deficits and might serve as early biomarkers for AD in the future.

EEG Radiotelemetry in Small Laboratory Rodents: A Powerful State-of-the Art Approach in Neuropsychiatric, Neurodegenerative, and Epilepsy Research.

EEG radiotelemetry plays an important role in the neurological characterization of transgenic mouse models of neuropsychiatric and neurodegenerative diseases as well as epilepsies providing valuable insights into underlying pathophysiological mechanisms and thereby facilitating the development of new translational approaches. We elaborate on the major advantages of nonrestraining EEG radiotelemetry in contrast to restraining procedures such as tethered systems or jacket systems containing recorders. Whereas a main disadvantage of the latter is their unphysiological, restraining character, telemetric EEG recording overcomes these disadvantages. It allows precise and highly sensitive measurement under various physiological and pathophysiological conditions. Here we present a detailed description of a straightforward successful, quick, and efficient technique for intraperitoneal as well as subcutaneous pouch implantation of a standard radiofrequency transmitter in mice and rats. We further present computerized 3D-stereotaxic placement of both epidural and deep intracerebral electrodes. Preoperative preparation of mice and rats, suitable anaesthesia, and postoperative treatment and pain management are described in detail. A special focus is on fields of application, technical and experimental pitfalls, and technical connections of commercially available radiotelemetry systems with other electrophysiological setups.

Altered theta oscillations and aberrant cortical excitatory activity in the 5XFAD model of Alzheimer's disease.

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by impairment of memory function. The 5XFAD mouse model was analyzed and compared with wild-type (WT) controls for aberrant cortical excitability and hippocampal theta oscillations by using simultaneous video-electroencephalogram (EEG) monitoring. Seizure staging revealed that 5XFAD mice exhibited cortical hyperexcitability whereas controls did not. In addition, 5XFAD mice displayed a significant increase in hippocampal theta activity from the light to dark phase during nonmotor activity. We also observed a reduction in mean theta frequency in 5XFAD mice compared to controls that was again most prominent during nonmotor activity. Transcriptome analysis of hippocampal probes and subsequent qPCR validation revealed an upregulation of Plcd4 that might be indicative of enhanced muscarinic signalling. Our results suggest that 5XFAD mice exhibit altered cortical excitability, hippocampal dysrhythmicity, and potential changes in muscarinic signaling.

Limited effects of an eIF2αS51A allele on neurological impairments in the 5xFAD mouse model of Alzheimer's disease.

Alzheimer's disease (AD) has been associated with increased phosphorylation of the translation initiation factor 2α (eIF2α) at serine 51. Increased phosphorylation of eIF2α alters translational control and may thereby have adverse effects on synaptic plasticity, learning, and memory. To analyze if increased levels of p-eIF2α indeed promote AD-related neurocognitive impairments, we crossed 5xFAD transgenic mice with an eIF2α(S51A) knock-in line that expresses the nonphosphorylatable eIF2α variant eIF2α(S51A). Behavioral assessment of the resulting mice revealed motor and cognitive deficits in 5xFAD mice that were, with the possible exception of locomotor hyperactivity, not restored by the eIF2α(S51A) allele. Telemetric intracranial EEG recordings revealed no measurable effects of the eIF2α(S51A) allele on 5xFAD-associated epileptic activity. Microarray-based transcriptome analyses showed clear transcriptional alterations in 5xFAD hippocampus that were not corrected by the eIF2α(S51A) allele. In contrast to prior studies, our immunoblot analyses did not reveal increased levels of p-eIF2α in the hippocampus of 5xFAD mice, suggesting that elevated p-eIF2α levels are not a universal feature of AD models. Collectively, our data indicate that 5xFAD-related pathologies do not necessarily require hyperphosphorylation of eIF2α to emerge; they also show that heterozygosity for the nonphosphorylatable eIF2α(S51A) allele has limited effects on 5xFAD-related disease manifestations.

Sex-specific cortical, hippocampal and thalamic whole genome transcriptome data from controls and a G72 schizophrenia mouse model.

OBJECTIVES: The G72 mouse model of schizophrenia represents a well-known model that was generated to meet the main translational criteria of isomorphism, homology and predictability of schizophrenia to a maximum extent. In order to get a more detailed view of the complex etiopathogenesis of schizophrenia, whole genome transcriptome studies turn out to be indispensable. Here we carried out microarray data collection based on RNA extracted from the retrosplenial cortex, hippocampus and thalamus of G72 transgenic and wild-type control mice. Experimental animals were age-matched and importantly, both sexes were considered separately. DATA DESCRIPTION: The isolated RNA from all three brain regions was purified, quantified und quality controlled before initiation of the hybridization procedure with SurePrint G3 Mouse Gene Expression v2 8  ×  60 K microarrays. Following immunofluorescent measurement und preprocessing of image data, raw transcriptome data from G72 mice and control animals were extracted and uploaded in a public database. Our data allow insight into significant alterations in gene transcript levels in G72 mice and enable the reader/user to perform further complex analyses to identify potential age-, sex- and brain-region-specific alterations in transcription profiles and related pathways. The latter could facilitate biomarker identification and drug research and development in schizophrenia research.

Sex- and region-specific cortical and hippocampal whole genome transcriptome profiles from control and APP/PS1 Alzheimer's disease mice.

A variety of Alzheimer's disease (AD) mouse models has been established and characterized within the last decades. To get an integrative view of the sophisticated etiopathogenesis of AD, whole genome transcriptome studies turned out to be indispensable. Here we carried out microarray data collection based on RNA extracted from the retrosplenial cortex and hippocampus of age-matched, eight months old male and female APP/PS1 AD mice and control animals to perform sex- and brain region specific analysis of transcriptome profiles. The results of our studies reveal novel, detailed insight into differentially expressed signature genes and related fold changes in the individual APP/PS1 subgroups. Gene ontology and Venn analysis unmasked that intersectional, upregulated genes were predominantly involved in, e.g., activation of microglial, astrocytic and neutrophilic cells, innate immune response/immune effector response, neuroinflammation, phagosome/proteasome activation, and synaptic transmission. The number of (intersectional) downregulated genes was substantially less in the different subgroups and related GO categories included, e.g., the synaptic vesicle docking/fusion machinery, synaptic transmission, rRNA processing, ubiquitination, proteasome degradation, histone modification and cellular senescence. Importantly, this is the first study to systematically unravel sex- and brain region-specific transcriptome fingerprints/signature genes in APP/PS1 mice. The latter will be of central relevance in future preclinical and clinical AD related studies, biomarker characterization and personalized medicinal approaches.

Pharmacoresistant Cav 2·3 (E-type/R-type) voltage-gated calcium channels influence heart rate dynamics and may contribute to cardiac impulse conduction.

Voltage-gated Ca(2+) channels regulate cardiac automaticity, rhythmicity and excitation-contraction coupling. Whereas L-type (Cav 1·2, Cav 1·3) and T-type (Cav 3·1, Cav 3·2) channels are widely accepted for their functional relevance in the heart, the role of Cav 2·3 Ca(2+) channels expressing R-type currents remains to be elucidated. We have investigated heart rate dynamics in control and Cav 2·3-deficient mice using implantable electrocardiogram radiotelemetry and pharmacological injection experiments. Autonomic block revealed that the intrinsic heart rate does not differ between both genotypes. Systemic administration of isoproterenol resulted in a significant reduction in interbeat interval in both genotypes. It remained unaffected after administering propranolol in Cav 2·3(-|-) mice. Heart rate from isolated hearts as well as atrioventricular conduction for both genotypes differed significantly. Additionally, we identified and analysed the developmental expression of two splice variants, i.e. Cav 2·3c and Cav 2·3e. Using patch clamp technology, R-type currents could be detected in isolated prenatal cardiomyocytes and be related to R-type Ca(2+) channels. Our results indicate that on the systemic level, the pharmacologically inducible heart rate range and heart rate reserve are impaired in Cav 2·3 (-|-) mice. In addition, experiments on Langendorff perfused hearts elucidate differences in basic properties between both genotypes. Thus, Cav 2·3 does not only contribute to the cardiac autonomous nervous system but also to intrinsic rhythm propagation.

Whole genome transcriptome data from the WT cortex and hippocampus of female and male control and APP/PS1 Alzheimer's disease mice.

A variety of Alzheimer disease (AD) mouse models has been established and characterized within the last decades. These models are generated to meet the principal criteria of AD isomorphism, homology and predictability to a maximum extent. To get an integrative view of the sophisticated etiopathogenesis of AD, whole genome transcriptome data analysis turns out to be indispensable. Here, we present a microarray-based transcriptome data collection based on RNA extracted from the retrosplenial (RS) cortex and the hippocampus of APP/PS1 AD mice and control animals. Experimental animals were age matched and importantly, both sexes were considered separately. Isolated RNA was purified, quantified und quality controlled prior to the hybridization procedure with SurePrint G3 Mouse Gene Expression v2 8 × 60K microarrays. Following immunofluorescent measurement und preprocessing/extraction of image data, raw transcriptome data were uploaded including differentially expressed gene candidates and related fold changes in APP/PS1 AD mice and controls. Our data allow further insight into alterations in gene transcript levels in APP/PS1 AD mice compared to controls and enable the reader/user to carry out complex transcriptome analysis to characterize potential age-, sex- and brain-region-specific alterations in e.g., neuroinflammatory, immunological, neurodegenerative and ion channel pathways.

Voltage-gated Ca(2+) channel mediated Ca(2+) influx in epileptogenesis.

Voltage- and ligand-gated ion channels are key elements in the etiopathogenesis of various forms of epilepsy. In this chapter, we present an overview of the functional implications of voltage-gated Ca(2+) channels in modulating internal Ca(2+) level fluctuations and generating ictiform/epileptiform cellular electrophysiological activity. A specific focus will be on the fascinating and evolving field of high-voltage activated (HVA) Non-L-type Ca(v)2.3 R-type channels and low-voltage activated (LVA) Ca(v)3.1-3.3 T-type Ca(2+) channels in the genesis of plateau potentials and excessive rebound bursting. Plateau potentials have been characterised in the hippocampus and were shown to be triggered by Ca(v)2.3 which subsequently activate CNG channels that mediate long-lasting plateaus. In the thalamocortical network, a complex ion channel armamentarium is involved in regulating a complex balance of burst and tonic mode activity. Recent findings point to an outstanding role of R- and T-type channels in both thalamocortical eurhythmia and pathophysiological -aberrations. Thus, pharmacological modulation of voltage-gated Ca(2+)-channels might prove more and more important in treatment of neurological and psychiatric disorder such as schizophrenia, mania, dementia and epilepsy.

Deep phenotyping and lifetime trajectories reveal limited effects of longevity regulators on the aging process in C57BL/6J mice.

Current concepts regarding the biology of aging are primarily based on studies aimed at identifying factors regulating lifespan. However, lifespan as a sole proxy measure for aging can be of limited value because it may be restricted by specific pathologies. Here, we employ large-scale phenotyping to analyze hundreds of markers in aging male C57BL/6J mice. For each phenotype, we establish lifetime profiles to determine when age-dependent change is first detectable relative to the young adult baseline. We examine key lifespan regulators (putative anti-aging interventions; PAAIs) for a possible countering of aging. Importantly, unlike most previous studies, we include in our study design young treated groups of animals, subjected to PAAIs prior to the onset of detectable age-dependent phenotypic change. Many PAAI effects influence phenotypes long before the onset of detectable age-dependent change, but, importantly, do not alter the rate of phenotypic change. Hence, these PAAIs have limited effects on aging.

Breeding of Cav2.3 deficient mice reveals Mendelian inheritance in contrast to complex inheritance in Cav3.2 null mutant breeding.

High voltage-activated Cav2.3 R-type Ca2+ channels and low voltage-activated Cav3.2 T-type Ca2+ channels were reported to be involved in numerous physiological and pathophysiological processes. Many of these findings are based on studies in Cav2.3 and Cav3.2 deficient mice. Recently, it has been proposed that inbreeding of Cav2.3 and Cav3.2 deficient mice exhibits significant deviation from Mendelian inheritance and might be an indication for potential prenatal lethality in these lines. In our study, we analyzed 926 offspring from Cav3.2 breedings and 1142 offspring from Cav2.3 breedings. Our results demonstrate that breeding of Cav2.3 deficient mice shows typical Mendelian inheritance and that there is no indication of prenatal lethality. In contrast, Cav3.2 breeding exhibits a complex inheritance pattern. It might be speculated that the differences in inheritance, particularly for Cav2.3 breeding, are related to other factors, such as genetic specificities of the mutant lines, compensatory mechanisms and altered sperm activity.

The Janus-like Association between Proton Pump Inhibitors and Dementia.

Early pharmacoepidemiological studies suggested that Proton Pump Inhibitors (PPIs) might increase the risk of Alzheimer's Disease (AD) and non-AD related dementias. These findings were supported by preclinical studies, specifically stressing the proamyloidogenic and indirect anticholinergic effects of PPIs. However, further large-scale pharmacoepidemiological studies showed inconsistent results on the association between PPIs and dementia. Pharmacodynamically, these findings might be related to the LXR/RXR-mediated amyloid clearance effect and anti-inflammatory action of PPIs. Further aspects that influence PPI effects on AD are related to patient- specific pharmacokinetic and pharmacogenomic characteristics. In conclusion, a personalized (individualized) medicinal approach is necessary to model and predict the potential harmful or beneficial effects of PPIs in AD and non-AD-related dementias in the future.

Enhanced hippocampal type II theta activity AND altered theta architecture in mice lacking the Cav3.2 T-type voltage-gated calcium channel.

T-type Ca2+ channels are assumed to contribute to hippocampal theta oscillations. We used implantable video-EEG radiotelemetry and qPCR to unravel the role of Cav3.2 Ca2+ channels in hippocampal theta genesis. Frequency analysis of spontaneous long-term recordings in controls and Cav3.2-/- mice revealed robust increase in relative power in the theta (4-8 Hz) and theta-alpha (4-12 Hz) ranges, which was most prominent during the inactive stages of the dark cycles. Urethane injection experiments also showed enhanced type II theta activity and altered theta architecture following Cav3.2 ablation. Next, gene candidates from hippocampal transcriptome analysis of control and Cav3.2-/- mice were evaluated using qPCR. Dynein light chain Tctex-Type 1 (Dynlt1b) was significantly reduced in Cav3.2-/- mice. Furthermore, a significant reduction of GABA A receptor δ subunits and GABA B1 receptor subunits was observed in the septohippocampal GABAergic system. Our results demonstrate that ablation of Cav3.2 significantly alters type II theta activity and theta architecture. Transcriptional changes in synaptic transporter proteins and GABA receptors might be functionally linked to the electrophysiological phenotype.

Spontaneous long-term and urethane induced hippocampal EEG power, activity and temperature data from mice lacking the Cav3.2 voltage-gated Ca2+ channel.

This article provides raw relative electroencephalographic (EEG) power, temperature and activity data from controls and Cav3.2 deficient mice. Radiotransmitter implantation was carried out in male experimental mice under ketamine/xylazine narcosis. Following a recovery period, radiotelemetric EEG recordings from the hippocampal CA1 region were obtained under spontaneous 24 h long-term conditions and post urethane injection. Relative EEG power values (%) for 2 s epochs were analysed for the following frequency ranges: delta 1 ( δ 1 , 0.5-4 Hz), delta 2 ( δ 2 , 1-4 Hz), theta 1 ( θ 1 , 4-8 Hz), theta 2 ( θ 2 , 4-12 Hz), alpha ( α , 8-12 Hz), sigma ( σ , 12-16 Hz), beta 1 ( ß 1 , 12-30 Hz), beta 2 ( ß 2 , 16-24 Hz), beta 3 ( ß 3 , 16-30 Hz), gamma low ( γ l o w , 30-50 Hz), gamma mid ( γ m i d , 50-70 Hz), gamma high ( γ h i g h , 70-100 Hz), gamma ripples ( γ r i p p l e s , 80-200 Hz), and gamma fast ripples ( γ f a s t r i p p l e s , 200-500 Hz). In addition, subcutaneous temperature and relative activity data were analysed for both the light and dark cycle of two long-term recordings. The same type of data was obtained post urethane injection. Detailed information is provided for the age and body weight of the experimental animals, the technical specifications of the radiofrequency transmitter, the stereotaxic coordinates for the intracerebral, deep and epidural, surface EEG electrodes, the electrode features, the filtering and sampling characteristics, the analysed EEG frequency bands and the data acquisition parameters. EEG power data, temperature and activity data are available at MENDELEY DATA (doi:10.17632/x53km5sby6.1, URL: http://dx.doi.org/10.17632/x53km5sby6.1). Raw EEG data are available at zenodo (https://zenodo.org/).

Isoflurane-sensitive presynaptic R-type calcium channels contribute to inhibitory synaptic transmission in the rat thalamus.

Because inhibitory synaptic transmission is a major mechanism of general anesthesia, we examined the effects of isoflurane on properties of GABAergic inhibitory currents in the reticular thalamic nucleus (nRT) in brain slices. The evoked IPSCs (eIPSCs) and spontaneous miniature synaptic currents (mIPSCs) of visualized nRT cells in young and adult rats were recorded. Consistent with postsynaptic effects on GABA(A) receptors, isoflurane prolonged the decay-time constants of both eIPSCs and mIPCSs. Surprisingly, isoflurane completely inhibited the amplitude of eIPSCs at clinically relevant concentrations (IC(50) of 240+/-20 microm), increased the paired-pulse ratio, and decreased the frequency of mIPSCs, indicating that presynaptic mechanisms may also contribute to the effects of isoflurane on IPSCs. The overall effect of isoflurane on eIPSCs in nRT cells was a decrease of net charge-transfer across the postsynaptic membrane. The application of 100 microm nickel (Ni(2+)) and the more specific R-type Ca(2+) channel blocker SNX-482 (0.5 microm) decreased eIPSC amplitudes, increased the paired-pulse ratio, and attenuated isoflurane-induced inhibition of eIPSCs. In addition, isoflurane potently blocked currents in recombinant human Ca(V)2.3 (alpha1E) channels with an IC(50) of 206 +/- 22 mum. Importantly, in vivo electroencephalographic (EEG) recordings in adult Ca(V)2.3 knock-out mice demonstrated alterations in isoflurane-induced burst-suppression activity. Because the thalamus has a key function in processing sensory information, sleep, and cognition, modulation of its GABAergic tone by presynaptic R-type Ca(2+) channels may contribute to the clinical effects of general anesthesia.