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1.
Neurosci Insights ; 15: 2633105520963045, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33345189

RESUMEN

Time series tools are part and parcel of modern day research. Their usage in the biomedical field; specifically, in neuroscience, has not been previously quantified. A quantification of trends can tell about lacunae in the current uses and point towards future uses. We evaluated the principles and applications of few classical time series tools, such as Principal Component Analysis, Neural Networks, common Auto-regression Models, Markov Models, Hidden Markov Models, Fourier Analysis, Spectral Analysis, in addition to diverse work, generically lumped under time series category. We quantified the usage from two perspectives, one, information technology professionals', other, researchers utilizing these tools for biomedical and neuroscience research. For understanding trends from the information technology perspective, we evaluated two of the largest open source question and answer databases of Stack Overflow and Cross Validated. We quantified the trends in their application in the biomedical domain, and specifically neuroscience, by searching literature and application usage on PubMed. While the use of all the time series tools continues to gain popularity in general biomedical and life science research, and also neuroscience, and so have been the total number of questions asked on Stack overflow and Cross Validated, the total views to questions on these are on a decrease in recent years, indicating well established texts, algorithms, and libraries, resulting in engineers not looking for what used to be common questions a few years back. The use of these tools in neuroscience clearly leaves room for improvement.

2.
Genomics ; 112(1): 552-566, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-30986427

RESUMEN

Heat shock protein 47 kDa (HSP47) serves as a client-specific chaperone, essential for collagen biosynthesis and its folding and structural assembly. To date, there is no comprehensive study on mutational hotspots. Using five different human mutational databases, we deduced a comprehensive list of human HSP47 mutations with 24, 67, 50, 43 and 2 deleterious mutations from the 1000 genomes data, gnomAD, COSMICv86, cBioPortal, and CanVar, respectively. We identified thirteen top-ranked missense mutations of HSP47 with the stringent cut-off of CADD score (>25) and Grantham score (≥151) as Ser76Trp, Arg103Cys, Arg116Cys, Ser159Phe, Arg167Cys, Arg280Cys, Trp293Cys, Gly323Trp, Arg339Cys, Arg373Cys, Arg377Cys, Ser399Phe, and Arg405Cys with the arginine-cysteine changes as the predominant mutations. These findings will assist in the evaluation of roles of HSP47 in collagen misfolding and human diseases such as cancer and bone disorders.


Asunto(s)
Proteínas del Choque Térmico HSP47/genética , Mutación Missense , Neoplasias/genética , Enfermedades Óseas/genética , Bases de Datos de Ácidos Nucleicos , Proteínas del Choque Térmico HSP47/química , Humanos , Conformación Proteica
3.
Curr Genomics ; 20(2): 90-99, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31555060

RESUMEN

After human genome sequencing and rapid changes in genome sequencing methods, we have entered into the era of rapidly accumulating genome-sequencing data. This has derived the development of several types of methods for representing results of genome sequencing data. Circular genome visual-ization tools are also critical in this area as they provide rapid interpretation and simple visualization of overall data. In the last 15 years, we have seen rapid changes in circular visualization tools after the de-velopment of the circos tool with 1-2 tools published per year. Herein we have summarized and revisited all these tools until the third quarter of 2018.

4.
J Exp Neurosci ; 13: 1179069519839990, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31001063

RESUMEN

Not much is known about disease prevalence, treatment outcomes, trained manpower, programs, and patients' awareness of diseases from South Asia, compared with the Western world. While other aspects are improving, the quantitative evaluation of awareness of diseases is lagging. Compared with other diseases, the situation for mental health disorders and addiction is worse. While no single study can fully quantify all aspects of awareness, a good starting point is to understand if increasing the number of mental health facilities is beneficial by understanding people's perception toward the likelihood of contracting various diseases, their preferred approach to treatment, and their perception of whether there are enough current facilities. We surveyed over 8000 families across several states of India and asked if they would treat a particular problem at home, visit a local healer, seek religious council, or go to a modern hospital for treatment. Our questions also included non-medical options to assess how likely people are to avoid trained medical help. We also asked people about their perceived likelihood of a family member ever suffering from (1) diarrhea, (2) high fever, (3) alcoholism, and (4) schizophrenia and other mental health problems. We reversed the order of diseases in our questions for a fraction of the population to evaluate the effect of order of questioning. Finally, we asked, if people feel they have enough local healers, religious places, general hospitals, de-addiction centers, and mental health facilities. Despite the taboo around mental health, many people claimed that their family members were unlikely to contract mental health or addiction problems, people recognized the severe paucity of mental health facilities and de-addiction centers. This raises hope for improving the mental health situation in India. We also found a significant relation between education levels and choices people make, underscoring the positive role education has in improving mental health.

5.
Drug Discov Today ; 24(1): 85-98, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30176358

RESUMEN

Maintenance of oral health is a major challenge in dentistry. Different materials have been used to treat various dental diseases, although treatment success is limited by features of the biomaterials used. To overcome these limitations, materials incorporated with nanoparticles (NPs) can be used in dental applications including endodontics, periodontics, tissue engineering, oral surgery, and imaging. The unique properties of NPs, including their surface:volume ratio, antibacterial action, physical, mechanical, and biological characteristics, and unique particle size have rendered them effective vehicles for dental applications. In this review, we provide insights into the various applications of NPs in dentistry, including their benefits, limitations, properties, actions and future potential.


Asunto(s)
Materiales Biocompatibles/uso terapéutico , Nanopartículas/uso terapéutico , Odontología , Humanos
6.
Free Radic Biol Med ; 129: 73-87, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30176346

RESUMEN

Wnts and the components of Wnt/ß-catenin signaling are widely expressed in midbrain and required to control the fate specification of dopaminergic (DAergic) neurons, a neuronal population that specifically degenerate in Parkinson's disease (PD). Accumulating evidence suggest that mitochondrial dysfunction plays a key role in pathogenesis of PD. Axin-2, a negative regulator of Wnt/ß-catenin signaling affects mitochondrial biogenesis and death/birth of new DAergic neurons is not fully explored. We investigated the functional role of Axin-2/Wnt/ß-catenin signaling in mitochondrial biogenesis and DAergic neurogenesis in 6-hydroxydopamine (6-OHDA) induced rat model of PD-like phenotypes. We demonstrate that single unilateral injection of 6-OHDA into the medial forebrain bundle (MFB) potentially dysregulates Wnt/ß-catenin signaling in substantia nigra pars compacta (SNpc). We used shRNA lentiviruses to genetically knockdown Axin-2 to up-regulate Wnt/ß-catenin signaling in SNpc in parkinsonian rats. Genetic knockdown of Axin-2 up-regulates Wnt/ß-catenin signaling by destabilizing the ß-catenin degradation complex in SNpc in parkinsonian rats. Axin-2 shRNA mediated activation of Wnt/ß-catenin signaling improved behavioural functions and protected the nigral DAergic neurons by increasing mitochondrial functionality in parkinsonian rats. Axin-2 shRNA treatment reduced apoptotic signaling, autophagy and ROS generation and improved mitochondrial membrane potential which promotes mitochondrial biogenesis in SNpc in parkinsonian rats. Interestingly, Axin-2 shRNA-mediated up-regulation of Wnt/ß-catenin signaling enhanced net DAergic neurogenesis by regulating proneural genes (Nurr-1, Pitx-3, Ngn-2, and NeuroD1) and mitochondrial biogenesis in SNpc in parkinsonian rats. Therefore, our data suggest that pharmacological/genetic manipulation of Wnt signaling that enhances the endogenous regenerative capacity of DAergic neurons may have implication for regenerative approaches in PD.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Portadoras/genética , Neuronas Dopaminérgicas/metabolismo , Neurogénesis/genética , Enfermedad de Parkinson Secundaria/genética , Proteínas Wnt/genética , Vía de Señalización Wnt , beta Catenina/genética , Proteínas Adaptadoras Transductoras de Señales/antagonistas & inhibidores , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Proteínas Portadoras/antagonistas & inhibidores , Proteínas Portadoras/metabolismo , Neuronas Dopaminérgicas/efectos de los fármacos , Neuronas Dopaminérgicas/patología , Regulación de la Expresión Génica , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Inyecciones Intraventriculares , Masculino , Haz Prosencefálico Medial/efectos de los fármacos , Haz Prosencefálico Medial/metabolismo , Haz Prosencefálico Medial/patología , Mesencéfalo/efectos de los fármacos , Mesencéfalo/metabolismo , Mesencéfalo/patología , Mitocondrias/genética , Mitocondrias/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Biogénesis de Organelos , Oxidopamina/administración & dosificación , Enfermedad de Parkinson Secundaria/inducido químicamente , Enfermedad de Parkinson Secundaria/metabolismo , Enfermedad de Parkinson Secundaria/patología , Porción Compacta de la Sustancia Negra/efectos de los fármacos , Porción Compacta de la Sustancia Negra/metabolismo , Porción Compacta de la Sustancia Negra/patología , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Ratas , Ratas Sprague-Dawley , Técnicas Estereotáxicas , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Wnt/metabolismo , beta Catenina/metabolismo
7.
PLoS One ; 13(8): e0201185, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30118488

RESUMEN

We propose a new approach, Bayesian Probability of Association (BPA) which takes into account the probability distributions of information and noise in the variables and uses Bayesian statistics to predict associations better than existing approaches. Our approach overcomes the limitations of linearity of the relationship and normality of the data, assumed by the Pearson correlation coefficient. It is different from the current measures of association because considering information separately from noise helps identify the association in information more accurately, makes the approach less sensitive to noise and also helps identify causal directions. We tested the approach on 15 datasets with no underlying association and on 75 datasets with known causal relationships and compared the results with other measures of association. No false associations were detected and true associations were predicted in more than 90% cases whereas the Pearson correlation coefficient and mutual information content predicted associations for less than half of the datasets.


Asunto(s)
Teorema de Bayes , Simulación por Computador , Interpretación Estadística de Datos , Bases de Datos Factuales/estadística & datos numéricos , Humanos , Teoría de la Información , Dinámicas no Lineales , Probabilidad , Relación Señal-Ruido , Programas Informáticos
8.
J Exp Neurosci ; 12: 1179069518767654, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29706766

RESUMEN

Phytomedicine has often been used as "alternative therapy," which in our opinion is unfortunate as it prevents its main actions being systematically studied, side effects explored, and toxicity tested, like all single-compound-based medicine. Our group is interested in finding which traditional or modern phytomedicines actually work and which are simply "working" through placebo, standardizing phytomedicine preparations, studying their toxicity, and finding active molecules in plants for modification and chemical synthesis as single compounds. Although fluctuation in efficacy due to seasonal and geographical variations in phytomedicine remains a concern, if well regulated, even plant extracts without isolated compounds can serve medicinal needs where single-compound options are currently not great. A potential concern with such phytomedicine is frequent mixing of ingredients in commercial formulations without test of synergism. Our study on the use of 2 traditional plants for Parkinson disease shows a clear lack of synergism, and to study nonsynergism better, we developed a new visualization approach. In this commentary, using our study on Parkinson disease as an example, we make a case for better evaluation of phytomedicines, especially testing for synergistic interactions. We also critique our own exploration of oxidative stress and few behavioral parameters alone to lay grounds for what we and hopefully others can do in future to extract more information from their phytomedicine studies. We hope this commentary acts as a good warning for anyone mixing 2 phytomedicines without testing.

9.
PLoS One ; 12(5): e0177254, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28510600

RESUMEN

Parkinson's disease remains as one of the most common debilitating neurodegenerative disorders. With the hopes of finding agents that can cure or reduce the pace of progression of the disease, we studied two traditional medicinal plants: Centella asiatica and Withania somnifera that have been explored in some recent studies. In agreement with the previous work on ethanol extracts of these two plants in mice model, we saw an improvement in oxidative stress profile as well as behavioral performance in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced Parkinson-like symptoms in Balb/c mice. Given the known potential of both the herbal extracts in improving Parkinson-like symptoms, we expected the combination of the two to show better results than either of the two but surprisingly there was no additivity in either oxidative stress or behavioural recovery. In fact, in some assays, the combination performed worse than either of the two individual constituents. This effect of mixtures highlights the need of testing mixtures in supplements market using enthomedicine. The necessity of comparing multiple groups in this study to get most information from the experiments motivated us to design a ladder-like visualization to show comparison with different groups that we call complete comparison display (CCD). In summary, we show the potential of Centella asiatica and Withania somnifera to ameliorate Parkinson's disorder.


Asunto(s)
Antiparkinsonianos/farmacología , Conducta Animal/efectos de los fármacos , Enfermedad de Parkinson/patología , Enfermedad de Parkinson/fisiopatología , Extractos Vegetales/farmacología , Triterpenos/farmacología , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/efectos adversos , Animales , Biomarcadores , Caspasas/metabolismo , Centella , Modelos Animales de Enfermedad , Glutatión/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Ratones , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Enfermedad de Parkinson/tratamiento farmacológico , Enfermedad de Parkinson/etiología , Superóxido Dismutasa/metabolismo , Withania/química
10.
Front Microbiol ; 6: 698, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26257708

RESUMEN

Gelling agents are required for formulating both solid and semisolid media, vital for the isolation of microorganisms. Gelatin was the first gelling agent to be discovered but it soon paved the way for agar, which has far superior material qualities. Source depletion, issues with polymerase-chain-reaction and inability to sustain extermophiles etc., necessitate the need of other gelling agents. Many new gelling agents, such as xantham gum, gellan gum, carrageenan, isubgol, and guar gum have been formulated, raising the hopes for the growth of previously unculturable microorganisms. We evaluate the progress in the development of gelling agents, with the hope that our synthesis would help accelerate research in the field.

11.
Bioinformation ; 11(4): 182-4, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26124557

RESUMEN

Microbial media has undergone several changes since its inception but some key challenges remain. In recent years, there has been exploration of several alternative nutrient sources, both to cater to the specificity in requirement of growth of "fussy microorganisms" and also to reduce costs for large-scale fermentation that is required for biotechnology. Our mini-review explores these developments and also points at lacunas in the present areas of exploration, such as a lack of concerted effort in pH and osmolarity regulation. We hope that our commentary provides direction for future research in microbial media.

12.
Bioinformation ; 11(4): 185-8, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26124558

RESUMEN

Many insects, including Drosophila melanogaster, have a rich repertoire of olfactory behavior. Combination of robust behavioral assays, physiological and molecular tools render D. melanogaster as highly suitable system for olfactory studies. The small number of neurons in the olfactory system of fruit flies, especially the number of sensory neurons in the larval stage, makes the exploration of sensory coding at all stages of its nervous system a potentially tractable goal, which is not possible in the foreseeable future in any mammalian preparation. Advances in physiological recordings, olfactory signaling and detailed analysis of behavior, can place larvae in a position to ask previously unanswerable questions.

13.
Front Neurosci ; 9: 503, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26834536

RESUMEN

Parkinson's disease is one of the most common neurodegenerative diseases. Animal models have contributed a large part to our understanding and therapeutics developed for treatment of PD. There are several more exhaustive reviews of literature that provide the initiated insights into the specific models; however a novel synthesis of the basic advantages and disadvantages of different models is much needed. Here we compare both neurotoxin based and genetic models while suggesting some novel avenues in PD modeling. We also highlight the problems faced and promises of all the mammalian models with the hope of providing a framework for comparison of various systems.

14.
Rev Neurosci ; 24(5): 527-36, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24077618

RESUMEN

With increasing use of various techniques to record optically and electrophysiologically from awake behaving animals and the growing developments of brain-machine interfaces, one might wonder if the use of acute-slice physiology is on its deathbed. Have we actually arrived at a stage where we can abandon the use of acute slices, with most of the information about brain functions coming from in vivo experiments? We do not believe that this is the case, given that our understanding of the nuts and bolts of the nervous system, such as ion channels and transporters in near-native state, neuronal compartmentalization, and single-neuron computation, is far from complete. We believe that in the foreseeable future, questions in these fields will still be best addressed by acute-slice physiology. We approach this review from the perspective of improving acute-slice physiology so it can continue to provide relevant and valuable contributions to neuroscience. We conclude that the death of acute-slice physiology is an obituary prematurely written, merely due to waxing and waning trends in science and the shortsightedness of investigators. Acute-slice physiology has at least one more life to live after the hype around new techniques has passed, but it needs to reinvent itself in light of current knowledge.


Asunto(s)
Encéfalo/citología , Electrofisiología , Neuronas/fisiología , Potenciales de Acción/fisiología , Animales , Muerte Celular , Electrofisiología/instrumentación
15.
Commun Integr Biol ; 6(2): e23501, 2013 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-23750304

RESUMEN

Alcohol addiction is a disease that includes a diverse set of phenotypes. Functional alcohol tolerance is an adaptation to the effects of alcohol that restores neuronal homeostatic balance while the drug is present. When the drug is suddenly withheld, these adaptations unbalance the nervous system and are thought to be the origin of some withdrawal symptoms. Withdrawal symptoms, which can be a motivating factor for alcoholics to relapse, are taken as evidence of physiological ethanol dependence. Both tolerance and withdrawal symptoms are diagnostic criteria for alcoholism. Recent studies have demonstrated that the larvae of Drosophila show conserved alcohol tolerance and withdrawal phenotypes indicating that Drosophila genetics can now be used in studying this endophenotype of alcohol addiction.

16.
Chem Senses ; 38(4): 315-23, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23363465

RESUMEN

We studied complete dose-response curves for 53 odorants in the third instar larvae of Drosophila melanogaster. All odorants, except one, elicited an attraction response. Some odorants also elicited a decrease from their peak response at higher concentrations. This concentration-dependent decrease in olfactory response could be due to either desensitization or repulsion, 2 possibilities that we cannot distinguish in our current assay. We observed high variations in factors like slopes, thresholds, and peaks of responses that, in agreement with previous studies, suggest that the responses of different receptors are quite different for the similar change in concentration of various ligands. We also observed that lower attraction thresholds predicted higher peak amplitude. This suggests that if odor responses encompassed wider concentration range than can be covered by the dynamic range of a single receptor, then responses tend to be high in magnitude.


Asunto(s)
Drosophila melanogaster/fisiología , Odorantes/análisis , Animales , Larva/fisiología , Neuronas Receptoras Olfatorias/fisiología , Olfato
17.
Curr Biol ; 22(24): 2338-41, 2012 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-23200990

RESUMEN

Physiological alcohol dependence is a key adaptation to chronic ethanol consumption that underlies withdrawal symptoms, is thought to directly contribute to alcohol addiction behaviors, and is associated with cognitive problems such as deficits in learning and memory. Based on the idea that an ethanol-adapted (dependent) animal will perform better in a learning assay than an animal experiencing ethanol withdrawal will, we have used a learning paradigm to detect physiological ethanol dependence in Drosophila. Moderate ethanol consumption initially degrades the capacity of larvae to learn, but they eventually adapt and are able to learn as well as ethanol-naive animals. However, withholding ethanol from ethanol-adapted larvae impairs learning. Ethanol reinstatement restores the capacity to learn, thus demonstrating cognitive dependence on ethanol. The larval nervous system also shows ethanol-withdrawal hyperexcitability. Larvae reach ethanol concentrations equivalent to 0.05 to 0.08 blood-alcohol concentration-levels that would be mildly intoxicating in humans. These ethanol-induced changes in learning are not the product of sensory deficits or state-dependent learning. This is the first demonstration of cognitive ethanol dependence in an invertebrate genetic model system.


Asunto(s)
Adaptación Fisiológica , Cognición/efectos de los fármacos , Etanol/efectos adversos , Neuronas/fisiología , Síndrome de Abstinencia a Sustancias/fisiopatología , Animales , Drosophila
18.
Front Neurosci ; 6: 112, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22855669

RESUMEN

Oxidative damage caused by free radicals plays an important role in the causation and progression of many diseases, including aging. Free-radical damage is countered by many mechanisms, including both active antioxidant enzymatic activity in our body and passive antioxidants. Antioxidant response of our body can accommodate increased oxidative damage in diseased states to a level but beyond that level, additional antioxidants are required to combat the increased stress. Apart from the regular dietary sources of antioxidants, many traditional herbal medicines demonstrate a potential to boost antioxidant activity. Rasayana chikitsa that deals with rejuvenation and revitalization is a branch of the Indian traditional medical system of ayurveda. We review some select herbs described in rasayana chikitsa that have been assessed by modern means for stimulating intrinsic antioxidant responses in humans. A critical evaluation of rasayana chikitsa will likely provide urgently needed, actual stimulants of our physiological antioxidant responses and not just more passive antioxidants to add to an already large catalog.

19.
PLoS One ; 7(5): e37394, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22624024

RESUMEN

Drosophila melanogaster has proven to be a useful model system for the genetic analysis of ethanol-associated behaviors. However, past studies have focused on the response of the adult fly to large, and often sedating, doses of ethanol. The pharmacological effects of low and moderate quantities of ethanol have remained understudied. In this study, we tested the acute effects of low doses of ethanol (∼7 mM internal concentration) on Drosophila larvae. While ethanol did not affect locomotion or the response to an odorant, we observed that ethanol impaired associative olfactory learning when the heat shock unconditioned stimulus (US) intensity was low but not when the heat shock US intensity was high. We determined that the reduction in learning at low US intensity was not a result of ethanol anesthesia since ethanol-treated larvae responded to the heat shock in the same manner as untreated animals. Instead, low doses of ethanol likely impair the neuronal plasticity that underlies olfactory associative learning. This impairment in learning was reversible indicating that exposure to low doses of ethanol does not leave any long lasting behavioral or physiological effects.


Asunto(s)
Etanol/toxicidad , Aprendizaje/efectos de los fármacos , Modelos Animales , Actividad Motora/efectos de los fármacos , Olfato/efectos de los fármacos , Animales , Cromatografía de Gases , Relación Dosis-Respuesta a Droga , Drosophila melanogaster , Larva/efectos de los fármacos , Larva/fisiología , Aprendizaje/fisiología , Actividad Motora/fisiología , Olfato/fisiología , Temperatura
20.
J Neurosci ; 32(8): 2814-23, 2012 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-22357864

RESUMEN

In sensory circuits of the brain, developmental changes in the expression and modulation of voltage-gated ion channels are a common occurrence, but such changes are often difficult to assign to clear functional roles. We have explored this issue in the binaural neurons of the medial superior olive (MSO), whose temporal precision in detecting the coincidence of binaural inputs dictates the resolution of azimuthal sound localization. We show that in MSO principal neurons of gerbils during the first week of hearing, a hyperpolarization-activated current (I(h)) progressively undergoes a 13-fold increase in maximal conductance, a >10-fold acceleration of kinetics, and, most surprisingly, a 30 mV depolarizing shift in the voltage dependence of activation. This period is associated with an upregulation of the hyperpolarization-activated and cyclic nucleotide-gated (HCN) channel subunits HCN1, HCN2, and HCN4 in the MSO, but only HCN1 and HCN4 were expressed strongly in principal neurons. I(h) recorded in nucleated patches from electrophysiologically mature MSO neurons (>P18) exhibited kinetics and an activation range nearly identical to the I(h) found in whole-cell recordings before hearing onset. These results indicate that the developmental changes in I(h) in MSO neurons can be explained predominantly by modulation from diffusible intracellular factors, and not changes in channel subunit composition. The exceptionally large modulatory changes in I(h), together with refinements in synaptic properties transform the coding strategy from one of summation and integration to the submillisecond coincidence detection known to be required for transmission of sound localization cues.


Asunto(s)
Fenómenos Biofísicos/fisiología , Regulación del Desarrollo de la Expresión Génica/fisiología , Activación del Canal Iónico/fisiología , Neuronas/fisiología , Factores de Edad , Análisis de Varianza , Androstadienos/farmacología , Animales , Fenómenos Biofísicos/efectos de los fármacos , Bucladesina/farmacología , Colforsina/farmacología , Canales Catiónicos Regulados por Nucleótidos Cíclicos/genética , Canales Catiónicos Regulados por Nucleótidos Cíclicos/metabolismo , Estimulación Eléctrica , Inhibidores Enzimáticos/farmacología , Femenino , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Gerbillinae , Imidazoles/farmacología , Técnicas In Vitro , Activación del Canal Iónico/efectos de los fármacos , Masculino , Neuronas/efectos de los fármacos , Núcleo Olivar/citología , Núcleo Olivar/crecimiento & desarrollo , Técnicas de Placa-Clamp , Piridinas/farmacología , Pirimidinas/farmacología , Wortmanina
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