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1.
Br J Dermatol ; 185(5): 988-998, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33959940

RESUMO

BACKGROUND: Genome-wide association studies (GWASs) have identified genes influencing skin ageing and mole count in Europeans, but little is known about the relevance of these (or other genes) in non-Europeans. OBJECTIVES: To conduct a GWAS for facial skin ageing and mole count in adults < 40 years old, of mixed European, Native American and African ancestry, recruited in Latin America. METHODS: Skin ageing and mole count scores were obtained from facial photographs of over 6000 individuals. After quality control checks, three wrinkling traits and mole count were retained for genetic analyses. DNA samples were genotyped with Illumina's HumanOmniExpress chip. Association testing was performed on around 8 703 729 single-nucleotide polymorphisms (SNPs) across the autosomal genome. RESULTS: Genome-wide significant association was observed at four genome regions: two were associated with wrinkling (in 1p13·3 and 21q21·2), one with mole count (in 1q32·3) and one with both wrinkling and mole count (in 5p13·2). Associated SNPs in 5p13·2 and in 1p13·3 are intronic within SLC45A2 and VAV3, respectively, while SNPs in 1q32·3 are near the SLC30A1 gene, and those in 21q21·2 occur in a gene desert. Analyses of SNPs in IRF4 and MC1R are consistent with a role of these genes in skin ageing. CONCLUSIONS: We replicate the association of wrinkling with variants in SLC45A2, IRF4 and MC1R reported in Europeans. We identify VAV3 and SLC30A1 as two novel candidate genes impacting on wrinkling and mole count, respectively. We provide the first evidence that SLC45A2 influences mole count, in addition to variants in this gene affecting melanoma risk in Europeans.


Assuntos
Melanoma , Envelhecimento da Pele , Adulto , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único/genética , Envelhecimento da Pele/genética
2.
BMC Genet ; 21(1): 104, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32928105

RESUMO

BACKGROUND: Prebreeding in plants is the activity designed to identify useful characteristics from wild germplasm and its integration in breeding programs. Prebreeding aims to introduce new variation into the populations of a species of interest. Pedigree analysis is a valuable tool for evaluation of variation in genebanks where pedigree maps are used to visualize and describe population structure and variation within these populations. Margot Forde Germplasm Centre (MFGC) is New Zealand's national forage genebank and holds a collection of ~ 75 species of the genus Trifolium, of which only a dozen have been taken through prebreeding programs. The main objective of this study was to construct pedigree maps and analyse patterns of relatedness for seven minor Trifolium species accessions contained at the MFGC. These species are Trifolium ambiguum, Trifolium arvense, Trifolium dubium, Trifolium hybridum, Trifolium medium, Trifolium subterraneum and the Trifolium repens x Trifolium occidentale interspecific hybrids. We present a history of Trifolium spp. prebreeding in New Zealand and inform breeders of possible alternative forage species to use. RESULTS: Pedigree data from accessions introduced between 1950 and 2016 were used and filtered based on breeding activity. Kinship levels among Trifolium spp. remained below 8% and no inbreeding was found. Influential ancestors that contributed largely to populations structure were identified. The Australian cultivar 'Monaro' had a strong influence over the whole population of accessions in T. ambiguum. T. subterraneum and T. repens x T. occidentale had the largest number of generations (3). T. ambiguum and T. medium had the highest cumulative kinship across the decades. CONCLUSIONS: We conclude that there are high levels of diversity in the seven Trifolium spp. studied. However, collection and prebreeding efforts must be strengthened to maximize utilization and bring useful genetic variation.


Assuntos
Genética Populacional , Linhagem , Melhoramento Vegetal , Trifolium/genética , Variação Genética , Genoma de Planta , Endogamia , Nova Zelândia , Trifolium/classificação
3.
Am J Case Rep ; 25: e944422, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38968161

RESUMO

BACKGROUND Leishmaniasis is a zoonosis with worldwide prevalence that causes dermal lesions and can be serious in humans. This report presents a case of cutaneous leishmaniasis (CL) that was apparently associated with a zoonotic transmission in a peri-urban area of the city of Portoviejo, Ecuador, close to mountainous and forested sites. CASE REPORT For 37 years, we have studied transmission of leishmaniasis in Ecuador, and have seen a wide variety of clinical presentations of the disease caused by different strains of the parasite Leishmania in patients, including pregnant women, without marked difference among them. CL without complications causes painless lesions of different clinical aspect. The present study reports a case of a 25-year-old woman presenting with severely inflamed, disseminated, and painful lesions of CL. The patient was not given antimonial treatment; however, local cryotherapy was given, together with topical anti-inflammatory and antibiotic ointment. All the lesions were observed to heal, and no amastigotes were found in smear stains after clinical healing. Since there was no reactivation after 1.5 years of follow-up, conventional antileishmanial treatment with meglumine antimoniate was not given to the patient. CONCLUSIONS This report shows the importance of a properly done epidemiological and clinical presumtive diagnosis, followed by parasitological confirmation, and the benefit of using an alternative treatment for vulnerable patients, such as this pregnant woman, for whom the therapy with pentavalent antimonials is not indicated. All observed lesions healed and no amastigotes were found in the smears after clinical healing.


Assuntos
Leishmaniose Cutânea , Complicações Parasitárias na Gravidez , Humanos , Feminino , Adulto , Gravidez , Equador , Complicações Parasitárias na Gravidez/tratamento farmacológico , Complicações Parasitárias na Gravidez/diagnóstico , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/tratamento farmacológico
4.
J Fish Biol ; 81(5): 1686-95, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23020568

RESUMO

The trophic interactions between the scyphozoan medusa Chrysaora plocamia and the palm ruff Seriolella violacea were investigated off northern Chile and showed that large numbers of hyperiid amphipods parasitizing the medusa may channel energy back to the fishes, which feed on the parasites. The biomass of hyperiids eaten by the fish was a function of the biomass of hyperiids parasitizing the medusa. This temporally available food supply may enhance fish recruitment. The large number of hyperiids parasitizing diverse jellyfish species represents a missing trophic link in current efforts to understand the effects of jellyfish blooms on marine food webs.


Assuntos
Anfípodes/fisiologia , Cadeia Alimentar , Perciformes/fisiologia , Cifozoários/parasitologia , Animais , Biomassa , Dieta
5.
Public Health Action ; 11(3): 146-154, 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34567991

RESUMO

BACKGROUND: WHO drug-resistant TB (DR-TB) treatment recommendations now emphasize all-oral regimens, recommending against certain injectable agents and deprioritizing others due to inferior safety and efficacy. Despite increasing focus on patient-centered care, we are not aware of systematic attempts to qualitatively document patients' perspectives on injectable agents. This may inform implementation of WHO guidelines, emphasizing the importance of consultation with affected communities. METHODS: Testimonies were provided by TB survivors who experienced hearing loss from treatment with injectable agents. Testimonies were submitted in writing in response to minimal, standardized, open-ended prompts. Participants provided a signed consent form (with options to participate anonymously or as a named co-author), and later gave input into the overall shape and recommendations of the article. RESULTS: Fourteen TB survivors in 12 countries contributed testimonies. The following common themes emerged: lack of access to appropriate testing, information, treatment, or a collaborative treatment environment; the power of supportive care and social environments; stigma and isolation from TB treatment itself and resultant disability; and inaccessibility of cochlear implants. CONCLUSIONS: Survivor testimonies indicate strong preferences for avoidance of injectable agents, supporting rapid implementation of revised WHO guidelines, as well as for quality and supportive care for both TB and disabilities.


CONTEXTE: Les recommandations de l'OMS pour le traitement de la TB pharmacorésistante (DR-TB) mettent désormais l'accent sur les schémas thérapeutiques entièrement par voie orale, préconisant de ne pas utiliser certains agents injectables et de ne plus donner la priorité à d'autres en raison d'une innocuité et d'une efficacité inférieures. Malgré l'attention accrue portée aux soins centrés sur le patient, nous ne connaissons aucune étude systématique ayant cherché à documenter de manière qualitative le point de vue des patients sur les agents injectables. Ce travail pourrait guider la mise en place des directives de l'OMS, en mettant l'accent sur l'importance de consulter les communautés concernées. MÉTHODES: Des personnes ayant survécu à une TB et ayant connu une perte d'audition due à un traitement par agents injectables ont apporté leurs témoignages. Les témoignages ont été soumis par écrit en réponse à des questions courtes, ouvertes et standardisées. Les participants ont signé un formulaire de consentement (avec possibilité de participer de manière anonyme ou en tant que coauteur nommé) et ont ensuite contribué au format général et aux recommandations de l'article. RÉSULTATS: Quatorze personnes ayant survécu à une TB provenant de 12 pays ont apporté leur témoignage. Les thématiques suivantes ont été fréquemment mentionnées : manque d'accès aux tests, informations et traitements appropriés ou à un environnement thérapeutique collaboratif ; importance des soins de soutien et de l'environnement social ; stigmatisation et isolement dus au traitement antituberculeux et handicaps qui en résultent ; et inaccessibilité aux implants cochléaires. CONCLUSIONS: Le témoignage des personnes ayant survécu à une TB indique qu'elles préfèrent nettement éviter les agents injectables, allant ainsi dans le sens d'une mise en place rapide des directives révisées de l'OMS, et qu'elles préfèrent des soins de qualité et de soutien pour la TB mais aussi pour les handicaps qui en résultent.

6.
Clin Transl Oncol ; 21(9): 1127-1134, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30778854

RESUMO

PURPOSE: This study aims to evaluate the association between composition of tumor-infiltrating lymphocytes (TIL) and expression of p16 in acral lentiginous melanoma (ALM), and their impact on prognosis. MATERIALS AND METHODS: A cohort of 148 surgical pathology specimens of ALM was studied. TIL were evaluated by immunohistochemical detection of CD3 and CD8, along with CD20, CD4, CD68, and CD163 in a subset of 43 cases. p16 protein expression was also investigated in all the cases. RESULTS: The median age was 66 years, median Breslow thickness was 6.0 mm, grade III TIL was found in 28.4% and lymph nodes were involved in 54.2%. Breslow thickness (p < 0.001), stage I-II (p < 0.001), negative lymph nodes (p < 0.001) and < 10% p16 (p = 0.01) were associated with longer survival. Grade III of TIL was associated with thinner Breslow thickness (p = 0.008) and lower mitosis (p = 0.047). A higher density of CD3 TIL was associated with male gender (p = 0.008), thinner Breslow thickness (p = 0.047), negative lymph node (p = 0.031), early stage (p = 0.046), and p16 nuclear expression of > 10% (p = 0.045). Higher CD8 TIL was associated with > p16 (p = 0.03). Survival analysis found that longer survival had a trend to be associated with high TIL (p = 0.090). Levels of CD3+ and CD8+ cells were correlated with those of CD4+, CD20+, CD68+ and CD163+ immune cells. CONCLUSIONS: Higher levels of TIL tend to be associated with better overall survival in ALM. Loss of expression of p16 is associated with lower levels of CD3+ and CD8+ TIL, indicating a probable relationship between p16 and TIL immune response in ALM .


Assuntos
Biomarcadores Tumorais/análise , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Lentigo/patologia , Linfócitos do Interstício Tumoral/imunologia , Melanoma/patologia , Neoplasias Cutâneas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Seguimentos , Humanos , Lentigo/imunologia , Lentigo/metabolismo , Masculino , Melanoma/imunologia , Melanoma/metabolismo , Pessoa de Meia-Idade , Prognóstico , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/metabolismo , Taxa de Sobrevida , Melanoma Maligno Cutâneo
7.
J Mol Biol ; 366(4): 1351-63, 2007 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-17204287

RESUMO

Understanding the initial steps of protein aggregation leading to the formation of amyloid fibrils remains a challenge. Here, the kinetics of such a process is determined for a misfolding protein model, ADA2h. The double nature of the very early kinetics suggests a step model of aggregation, where the denatured polypeptide folds into an aggregated beta-intermediate that subsequently reorganises into a more organised beta-sheet-richer structure that finally results in amyloid fibre formation. To determine the regions of the protein involved in amyloidosis, we have analysed a series of mutants previously made to study ADA2h folding. Using the algorithm TANGO, we have designed mutants that should enhance or decrease aggregation. Experimental analysis of the mutants shows that the C terminus of the molecule (comprising the last and edge beta-strand) is the major contributor to amyloid fibril formation, in good agreement with theoretical predictions. Comparison with proteins with similar topology reveals that family folds do not necessarily share the same principles of protein folding and/or aggregation.


Assuntos
Amiloide/metabolismo , Carboxipeptidases A/química , Carboxipeptidases A/metabolismo , Conformação Proteica , Algoritmos , Estabilidade Enzimática , Previsões , Modelos Moleculares , Mutação Puntual , Dobramento de Proteína , Estrutura Secundária de Proteína
8.
Clin Transl Oncol ; 19(12): 1478-1488, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28577153

RESUMO

PURPOSE: Acral lentiginous melanoma (ALM) is a poor prognosis subtype and is the most prevalent in non-Caucasian populations. The presence of tumor infiltrating lymphocytes (TILs) has been associated with poor prognosis in melanoma. A large cohort of ALM cases was studied to determine status of TIL and its association with outcome. METHODS: All patients with cutaneous melanoma presenting from 2005 to 2012 at Instituto Nacional de Enfermedades Neoplasicas in Peru were retrospectively identified. Clinicopathological information was obtained from the medical charts. A prospective evaluation of TIL was performed. Analysis of association between ALM and clinicopathological features including TIL as well as survival analysis compared the outcome of ALM to whole group and extremity NALM was performed. RESULTS: 537 ALM from a total of 824 cutaneous melanoma cases were studied. Older age (p = 0.022), higher Breslow (p = 0.008) and ulceration (p < 0.001) were found to be more frequent in ALM. Acral had worse overall survival (OS) compared with the whole group (p = 0.04). Clinical stage (CS) I-II patients had a median OS of 5.3 (95% CI 4.3-6.2) for ALM and 9.2 (95% CI 5.0-7.0) for extremity NALM (p = 0.016). Grade 0 (absence of TIL), I, II and III were found in 7.5, 34.5, 32.1, and 25.9%, respectively. Lower TIL grade was associated with larger tumor size (p = 0.003), higher Breslow (p = 0.001), higher Clark level (p = 0.007), higher CS (p = 0.002), extremity location (p = 0.048), histological subtype ALM (p = 0.024) and better OS (p = 0.001). CONCLUSIONS: ALM is highly prevalent in Peru and carries poor outcome. Lower TIL levels were associated with poor outcome and ALM.


Assuntos
Extremidades/patologia , Linfócitos do Interstício Tumoral/patologia , Melanoma/patologia , Neoplasias Cutâneas/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Extremidades/cirurgia , Feminino , Seguimentos , Humanos , América Latina , Masculino , Melanoma/cirurgia , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Neoplasias Cutâneas/cirurgia , Taxa de Sobrevida , Adulto Jovem , Melanoma Maligno Cutâneo
9.
J Mol Biol ; 283(5): 1027-36, 1998 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-9799641

RESUMO

The transition state for the folding pathway of the activation domain of human procarboxypeptidase A2 (ADA2h) has been analyzed by the protein engineering approach. Recombinant ADA2h is an 81-residue globular domain with no disulfide bridges or cis-prolyl bonds, which follows a two-state folding transition. Its native fold is arranged in two alpha-helices packing against a four-stranded beta-sheet. Application of the protein engineering analysis for 20 single-point mutants spread throughout the whole sequence indicates that the transition state for this molecule is quite compact, possessing some secondary structure and a hydrophobic core in the process of being consolidated. The core (folding nucleus) is made by the packing of alpha-helix 2 and the two central beta-strands. The other two strands, at the edges of the beta-sheet, and alpha-helix 1 seem to be completely unfolded. These results, together with previous analysis of ADA2h with either of its two alpha-helices stabilized through improved local interactions, suggest that alpha-helix 1 does not contribute to the folding nucleus, even though it is partially folded in the denatured state under native conditions. On the other hand, alpha-helix 2 folds partly in the transition state and is part of the folding nucleus. It is suggested that a good strategy to improve folding speed in proteins would be to stabilize the helices that are not folded in the denatured state but are partly present in the transition state. Comparison with other proteins shows that there is no clear relationship between fold and/or size with folding speed and level of structure in the transition state of proteins.


Assuntos
Carboxipeptidases/química , Precursores Enzimáticos/química , Sequência de Aminoácidos , Carboxipeptidases/genética , Carboxipeptidases A , Ativação Enzimática , Precursores Enzimáticos/genética , Humanos , Técnicas In Vitro , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação Puntual , Desnaturação Proteica , Engenharia de Proteínas , Dobramento de Proteína , Estrutura Secundária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Termodinâmica , Ureia
10.
Protein Sci ; 4(9): 1792-800, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8528077

RESUMO

The activation process of porcine pancreatic procarboxypeptidase B (pro-CPB) has been studied in detail by a number of complementary methodologies, and a description of the molecular events that lead to the generation of active carboxypeptidase B (CPB) has been deduced. The generated CPB participates in the degradation of its own activation segment by excising C-terminal residues from fragments produced by tryptic proteolysis. The trimming action of CPB is, however, not essential for the release of a fully functional enzyme, in contrast to what was previously reported for porcine procarboxypeptidase A (pro-CPA). In the model presented here, the activation process is solely dependent on the first tryptic cleavage, at the limit between the activation segment and the enzyme region, and the former piece loses all of its inhibitory capacity once severed from the proenzyme. The use of heterologous inhibitors of CPB activity during the study of the tryptic activation process of pro-CPB has been required for the capture of short-lived, otherwise nondetectable, intermediates. This has allowed a complete description of the process and shown that the first proteolytic action of trypsin can also take place on a second target bond. Structural considerations that take into account the three-dimensional structures of the A and B forms of the proenzymes lead us to propose that the differences in conformation at the region that connects the globular activation domain to the enzyme are the main responsible elements for the differences observed in the activation processes of both proenzymes.


Assuntos
Carboxipeptidases/metabolismo , Precursores Enzimáticos/metabolismo , Pâncreas/enzimologia , Sequência de Aminoácidos , Aminoácidos/análise , Aminoácidos/metabolismo , Animais , Carboxipeptidase B , Carboxipeptidases/química , Cromatografia Líquida de Alta Pressão , Eletroforese em Gel de Poliacrilamida , Ativação Enzimática , Precursores Enzimáticos/química , Concentração de Íons de Hidrogênio , Cinética , Dados de Sequência Molecular , Suínos , Tripsina/metabolismo
11.
Protein Sci ; 9(9): 1700-8, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11045616

RESUMO

The activation domain of human procarboxypeptidase A2 (ADA2h) aggregates following thermal or chemical denaturation at acidic pH. The aggregated material contains well-defined ordered structures with all the characteristics of the fibrils associated with amyloidotic diseases. Variants of ADA2h containing a series of mutations designed to increase the local stability of each of the two helical regions of the protein have been found to have a substantially reduced propensity to form fibrils. This arises from a reduced tendency of the denatured species to aggregate rather than from a change in the overall stability of the native state. The reduction in aggregation propensity may result from an increase in the stability of local relative to longer range interactions within the polypeptide chain. These findings show that the intrinsic ability of a protein to form amyloid can be altered substantially by protein engineering methods without perturbing significantly its overall stability or activity. This suggests new strategies for combating diseases associated with the formation of aggregated proteins and for the design of novel protein or peptide therapeutics.


Assuntos
Amiloide/biossíntese , Carboxipeptidases/química , Precursores Enzimáticos/química , Engenharia de Proteínas , Sequência de Aminoácidos , Amiloide/química , Carboxipeptidases/genética , Carboxipeptidases/ultraestrutura , Carboxipeptidases A , Dicroísmo Circular , Precursores Enzimáticos/genética , Precursores Enzimáticos/ultraestrutura , Humanos , Microscopia Eletrônica , Dados de Sequência Molecular , Mutagênese , Desnaturação Proteica , Estrutura Terciária de Proteína
12.
FEBS Lett ; 472(1): 27-33, 2000 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-10781799

RESUMO

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used to monitor hydrogen exchange on entire proteins. Two alternative methods have been used to carry out the hydrogen exchange studies, exchanging deuteron (H to D experiments) or proton (D to H experiments). In the former case, the use of a deuterated matrix has made possible to overcome back-exchange problems and attain reproducible results. The methods presented have been used to determine the slow exchange core of the potato carboxypeptidase inhibitor in different folding states, and to differentially compare the activation domain of human procarboxypeptidase A2 versus three site-directed mutants of different conformational stability. In this work, we show that by using MALDI-TOF MS to monitor hydrogen exchange in entire proteins, it is possible to rapidly check the folding state of a protein and characterize mutational effects on protein conformation and stability, while requiring minimal amounts of sample.


Assuntos
Carboxipeptidases/química , Precursores Enzimáticos/química , Proteínas de Plantas/química , Carboxipeptidases/genética , Carboxipeptidases A , Domínio Catalítico , Deutério , Precursores Enzimáticos/genética , Humanos , Hidrogênio , Mutagênese Sítio-Dirigida , Proteínas de Plantas/genética , Inibidores de Proteases , Conformação Proteica , Dobramento de Proteína , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
13.
Rev Invest Clin ; 41(4): 345-50, 1989.
Artigo em Espanhol | MEDLINE | ID: mdl-2698501

RESUMO

Ninety three patients with multiple myeloma (MM) were treated with cyclophosphamide, vincristine, melphalan, prednisone and adriamycin (C.O.M.P.A.). Their median age was 60.9 years and sixty five were males. Seven patients were in stage I-A; 25 in II-A; 33 in III-A and 28 in III-B. Complete remission (CR) was achieved in 61 (65.6%), partial remission (PR) in 18 (19.3%) and no response in 14 (15%). At present, the mean survival of the CR group, is 32.3 months (10 to 78), and of the PR 11.2 months (6 to 18). The actuarial survival of the CR group is 37.9 months. A hemoglobin level lower than 8.5 g/dL, serum creatinine higher than 2.0 mg/dL, and stage III disease were factors that together negatively influenced in both response to treatment and survival. Proteinuria did not affect response, but it was a negative factor for survival. Thirty percent of deaths were due to infection, and 24.5% to myeloma activity associated with infection. We conclude that this five drug combination (C.O.M.P.A.) achieves a high percentage of complete remissions, but does not differ significantly from other reported schemes in the mean survival obtained for multiple myeloma.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Adulto , Idoso , Ciclofosfamida/administração & dosagem , Doxorrubicina/administração & dosagem , Avaliação de Medicamentos , Feminino , Humanos , Masculino , Melfalan/administração & dosagem , Pessoa de Meia-Idade , Mieloma Múltiplo/mortalidade , Prednisona/administração & dosagem , Indução de Remissão , Vincristina/administração & dosagem
14.
Arch Soc Esp Oftalmol ; 75(6): 389-96, 2000 Jun.
Artigo em Espanhol | MEDLINE | ID: mdl-11151183

RESUMO

PURPOSE: To investigate the possible participation of glutamate in the neurotransmission of the rat geniculo-cortical pathway. METHODS: In a first set of experiments, we studied the effects of microiontophoresis of kynurenate, a broad spectrum antagonist of glutamate receptors, on the excitation evoked in visual cortex cells by electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract. Cell activity was determined by extracellular unit recordings. In a second set of experiments, we studied the effects of electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract on the release of glutamate and aspartate in the visual cortex in vivo. Push pull perfusions were made in the visual cortex and the amino acids contents of the perfusates were analysed by high performance liquid chromatography. RESULTS: Microiontophoresis of kynureate in area 17 cells selectively supressed the excitatory response to dorsal geniculate nucleus and optic tract stimulation. On the other hand, stimulation of these structures significantly increased glutamate, but not aspartate, release in area 17. CONCLUSIONS: These results demonstrate that glutamate is the neurotransmitter of the geniculo-cortical pathway in the rat.


Assuntos
Corpos Geniculados/fisiologia , Ácido Glutâmico/fisiologia , Transmissão Sináptica/fisiologia , Córtex Visual/fisiologia , Animais , Ácido Aspártico/fisiologia , Antagonistas de Aminoácidos Excitatórios/administração & dosagem , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Corpos Geniculados/efeitos dos fármacos , Iontoforese , Ácido Cinurênico/administração & dosagem , Ácido Cinurênico/farmacologia , Masculino , Ratos , Transmissão Sináptica/efeitos dos fármacos , Córtex Visual/efeitos dos fármacos
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