Causality and functional relevance of BRCA1 and BRCA2 pathogenic variants in non-high-grade serous ovarian carcinomas.

The identification of causal BRCA1/2 pathogenic variants (PVs) in epithelial ovarian carcinoma (EOC) aids the selection of patients for genetic counselling and treatment decision-making. Current recommendations therefore stress sequencing of all EOCs, regardless of histotype. Although it is recognised that BRCA1/2 PVs cluster in high-grade serous ovarian carcinomas (HGSOC), this view is largely unsubstantiated by detailed analysis. Here, we aimed to analyse the results of BRCA1/2 tumour sequencing in a centrally revised, consecutive, prospective series including all EOC histotypes. Sequencing of n = 946 EOCs revealed BRCA1/2 PVs in 125 samples (13%), only eight of which were found in non-HGSOC histotypes. Specifically, BRCA1/2 PVs were identified in high-grade endometrioid (3/20; 15%), low-grade endometrioid (1/40; 2.5%), low-grade serous (3/67; 4.5%), and clear cell (1/64; 1.6%) EOCs. No PVs were identified in any mucinous ovarian carcinomas tested. By re-evaluation and using loss of heterozygosity and homologous recombination deficiency analyses, we then assessed: (1) whether the eight 'anomalous' cases were potentially histologically misclassified and (2) whether the identified variants were likely causal in carcinogenesis. The first 'anomalous' non-HGSOC with a BRCA1/2 PV proved to be a misdiagnosed HGSOC. Next, germline BRCA2 variants, found in two p53-abnormal high-grade endometrioid tumours, showed substantial evidence supporting causality. One additional, likely causal variant, found in a p53-wildtype low-grade serous ovarian carcinoma, was of somatic origin. The remaining cases showed retention of the BRCA1/2 wildtype allele, suggestive of non-causal secondary passenger variants. We conclude that likely causal BRCA1/2 variants are present in high-grade endometrioid tumours but are absent from the other EOC histotypes tested. Although the findings require validation, these results seem to justify a transition from universal to histotype-directed sequencing. Furthermore, in-depth functional analysis of tumours harbouring BRCA1/2 variants combined with detailed revision of cancer histotypes can serve as a model in other BRCA1/2-related cancers. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

GEIS-SEHOP clinical practice guidelines for the treatment of rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most frequent soft tissue sarcoma (STS) in children and adolescents. In Spain the annual incidence is 4.4 cases per million children < 14 years. It is an uncommon neoplasm in adults, but 40% of RMS are diagnosed in patients over 20 years of age, representing 1% of all STS in this age group. RMS can appear anywhere in the body, with some sites more frequently affected including head and neck, genitourinary system and limbs. Assessment of a patient with suspicion of RMS includes imaging studies (MRI, CT, PET-CT) and biopsy. All patients with RMS should receive chemotherapy, either at diagnosis in advanced or metastatic stages, or after initial resection in early local stages. Local control includes surgery and/or radiotherapy depending on site, stage, histology and response to chemotherapy. This guide provides recommendations for diagnosis, staging and treatment of this neoplasm.

#EUROmicroMOOC: using Twitter to share trends in Microbiology worldwide.

Twitter is one of the most popular social media networks that, in recent years, has been increasingly used by researchers as a platform to share science and discuss ongoing work. Despite its popularity, Twitter is not commonly used as a medium to teach science. Here, we summarize the results of #EUROmicroMOOC: the first worldwide Microbiology Massive Open Online Course taught in English using Twitter. Content analytics indicated that more than 3 million users saw posts with the hashtag #EUROmicroMOOC, which resulted in over 42 million Twitter impressions worldwide. These analyses demonstrate that free Microbiology MOOCs shared on Twitter are valuable educational tools that reach broad audiences throughout the world. We also describe our experience teaching an entire Microbiology course using Twitter and provide recommendations when using social media to communicate science to a broad audience.

Practical guidance for mismatch repair-deficiency testing in endometrial cancer.

Background: Mismatch repair (MMR)-deficiency analysis is increasingly recommended for all endometrial cancers, as it identifies Lynch syndrome patients, and is emerging as a prognostic classifier to guide adjuvant treatment. The aim of this study was to define the optimal approach for MMR-deficiency testing and to clarify discrepancies between microsatellite instability (MSI) analysis and immunohistochemical (IHC) analysis of MMR protein expression. Patients and methods: Six hundred ninety- six endometrial cancers were analyzed for MSI (pentaplex panel) and MMR protein expression (IHC). Agreement between methodologies was calculated using Cohen's Kappa. MLH1 promoter hypermethylation, dinucleotide microsatellite markers and somatic MMR and POLE exonuclease domain (EDM) gene variants (using next-generation/Sanger sequencing) were analyzed in discordant cases. Results: MSI was found in 180 patients. Complete loss of expression of one or more MMR proteins was observed in 196 cases. A PMS2- and MSH6-antibody panel detected all cases with loss of MMR protein expression. The results of MSI and MMR protein expression were concordant in 655/696 cases (kappa = 0.854, P < 0.001). Ambiguous cases (n = 41, 6%) included: subclonal loss of MMR protein expression (n = 18), microsatellite stable or MSI-low cases with loss of MMR protein expression (n = 20), and MSI-low or MSI-high cases with retained MMR protein expression (n = 3). Most of these cases could be explained by MLH1 promoter hypermethylation. Five of seven cases with solitary loss of PMS2 or MSH6 protein expression carried somatic gene variants. Two MSI-high cases with retained MMR protein expression carried a POLE-EDM variant. Conclusion: MSI and IHC analysis are highly concordant in endometrial cancer. This holds true for cases with subclonal loss of MMR protein expression. Discordant MMR-proficient/MSI-high cases (<1%), may be explained by POLE-EDM variants.

Gliomas de bajo grado: revisión de 10 años / Low-grade gliomas: Review of 10 years

INTRODUCCIÓN: Los tumores del SNC son los tumores sólidos más frecuentes en la edad pediátrica. Dentro de ellos los gliomas de bajo grado constituyen el tipo más común de tumor del SNC en niños, representando hasta el 30-50% de los mismos. PACIENTES Y MÉTODOS: Análisis retrospectivo de las características epidemiológicas, manifestaciones clínicas, localización del tumor, histología, tipo de tratamiento si lo ha recibido, evolución y secuelas a largo plazo de 111 pacientes diagnosticados de glioma de bajo grado en el Hospital Infantil Universitario Niño Jesús de Madrid entre enero de 2002 y diciembre de 2011. RESULTADOS: De los 111 pacientes 57 eran niños y 54 niñas. La edad media fue de 7,26 años (intervalo 2 meses-19 anos). Los síntomas de presentación más frecuentes fueron la cefalea (27%) y los vómitos (19%). Las localizaciones más frecuentes fueron los hemisferios cerebrales (38%), seguido del tronco cerebral (27,4%) y del cerebelo (18,5%). Se realizó estudio histológico en 89 pacientes (80,18%), siendo el astrocitoma pilocítico el tipo histológico más frecuente. Se realizó biopsia diagnóstica en 20 pacientes (22,5%), resección parcial en 38 pacientes (42,7%) y resección total en 31 pacientes (34,8%). Recibieron quimioterapia 16 pacientes (14%) y radioterapia 18 pacientes (16%). La supervivencia global fue del 88,3%. Un paciente presentó secuelas auditivas, 5 pacientes presentaron secuelas visuales y 4 pacientes secuelas endocrinas. CONCLUSIONES: El tipo histológico más frecuente es el astrocitoma pilocítico. La supervivencia global fue del 88,3%. Solo el 9% de los pacientes presentaron algún tipo de secuela auditiva, visual o endocrinológica

INTRODUCTION: Central nervous system (CNS) tumors are the most common solid tumors in children. Among these, the low-grade gliomas are the most common type, accounting for up to 30-50% of them. PATIENTS AND METHODS: A retrospective analysis was carried out on the epidemiology, clinical characteristics, tumor location, histology, treatment, outcome and long-term sequelae of 111 patients diagnosed with low-grade glioma in the Nino˜ Jesús Children's Hospital of Madrid from January 2002 to December 2011. RESULTS: Of the 111 patients, there were 57 boys and 54 girls. The mean age was 7.26 years (range, 2 months - 19 years). The most common symptoms of presentation were headache (27%) and vomiting (19%). The most common locations were the cerebral hemispheres (38%), followed by the brainstem (27.4%), and cerebellum (18.5%). Histological examination was performed in 89 patients (80.18%). Pilocytic astrocytoma was the most common histological type. Diagnostic biopsy was performed in 20 patients (22.5%), partial resection in 38 patients (42.7%), and total resection in 31 patients (34.8%). Sixteen patients received chemotherapy (14%), and eighteen patients received radiotherapy (16%). Overall survival was 88.3%. Long term hearing, visual and endocrine sequelae were note in 1, 5, and 4 patients, respectively. CONCLUSIONS: The most common histological type is pilocytic astrocytoma. Overall survival was 88.3%. Only 9% of patients had some kind or auditory, visual or endocrine sequelae

[Low-grade gliomas: review of 10 years]. / Gliomas de bajo grado: revisión de 10 años.

INTRODUCTION: Central nervous system (CNS) tumors are the most common solid tumors in children. Among these, the low-grade gliomas are the most common type, accounting for up to 30-50% of them. PATIENTS AND METHODS: A retrospective analysis was carried out on the epidemiology, clinical characteristics, tumor location, histology, treatment, outcome and long-term sequelae of 111 patients diagnosed with low-grade glioma in the Niño Jesús Children's Hospital of Madrid from January 2002 to December 2011. RESULTS: Of the 111 patients, there were 57 boys and 54 girls. The mean age was 7.26 years (range, 2 months - 19 years). The most common symptoms of presentation were headache (27%) and vomiting (19%). The most common locations were the cerebral hemispheres (38%), followed by the brainstem (27.4%), and cerebellum (18.5%). Histological examination was performed in 89 patients (80.18%). Pilocytic astrocytoma was the most common histological type. Diagnostic biopsy was performed in 20 patients (22.5%), partial resection in 38 patients (42.7%), and total resection in 31 patients (34.8%). Sixteen patients received chemotherapy (14%), and eighteen patients received radiotherapy (16%). Overall survival was 88.3%. Long term hearing, visual and endocrine sequelae were note in 1, 5, and 4 patients, respectively. CONCLUSIONS: The most common histological type is pilocytic astrocytoma. Overall survival was 88.3%. Only 9% of patients had some kind or auditory, visual or endocrine sequelae.

GSK-3ß signaling determines autophagy activation in the breast tumor cell line MCF7 and inclusion formation in the non-tumor cell line MCF10A in response to proteasome inhibition.

The ubiquitin-proteasome system and the autophagy-lysosome pathway are the two main mechanisms for eukaryotic intracellular protein degradation. Proteasome inhibitors are used for the treatment of some types of cancer, whereas autophagy seems to have a dual role in tumor cell survival and death. However, the relationship between both pathways has not been extensively studied in tumor cells. We have investigated both proteolytic systems in the human epithelial breast non-tumor cell line MCF10A and in the human epithelial breast tumor cell line MCF7. In basal condition, tumor cells showed a lower proteasome function but a higher autophagy activity when compared with MCF10A cells. Importantly, proteasome inhibition (PI) leads to different responses in both cell types. Tumor cells showed a dose-dependent glycogen synthase kinase-3 (GSK-3)ß inhibition, a huge increase in the expression of the transcription factor CHOP and an active processing of caspase-8. By contrast, MCF10A cells fully activated GSK-3ß and showed a lower expression of both CHOP and processed caspase-8. These molecular differences were reflected in a dose-dependent autophagy activation and cell death in tumor cells, while non-tumor cells exhibited the formation of inclusion bodies and a decrease in the cell death rate. Importantly, the behavior of the MCF7 cells can be reproduced in MCF10A cells when GSK-3ß and the proteasome were simultaneously inhibited. Under this situation, MCF10A cells strongly activated autophagy, showing minimal inclusion bodies, increased CHOP expression and cell death rate. These findings support GSK-3ß signaling as a key mechanism in regulating autophagy activation or inclusion formation in human tumor or non-tumor breast cells, respectively, which may shed new light on breast cancer control.

Increased frequency of 20q gain and copy-neutral loss of heterozygosity in mismatch repair proficient familial colorectal carcinomas.

Many hereditary nonpolyposis colorectal cancers (CRCs) cannot be explained by Lynch syndrome. Other high penetrance genetic risk factors are likely to play a role in these mismatch repair (MMR)-proficient CRC families. Because genomic profiles of CRC tend to vary with CRC susceptibility syndromes, our aim is to analyze the genomic profile of MMR-proficient familial CRC to obtain insight into the biological basis of MMR-proficient familial CRC. We studied 30 MMR-proficient familial colorectal carcinomas, from 15 families, for genomic aberrations, including gains, physical losses, and copy-neutral loss of heterozygosity LOH (cnLOH) using SNP array comparative genomic hybridization. In addition, we performed somatic mutation analysis for KRAS, BRAF, PIK3CA and GNAS. The frequency of 20q gain (77%) is remarkably increased when compared with sporadic CRC, suggesting that 20q gain is involved in tumor progression of familial CRC. There is also a significant increase in the frequency of cnLOH and, as a consequence, a reduced frequency of physical loss compared with sporadic CRC. The most frequent aberrations observed included gains of 7p, 7q, 8q, 13q, 20p and 20q as well as physical losses of 17p, 18p and 18q. Most of these changes are also observed in sporadic CRC. Mutations in KRAS were identified in 37% of the MMR-proficient CRCs, and mutations in BRAF were identified in 16%. No mutations were identified in PIK3CA or chromosome 20 candidate gene GNAS. We show that the patterns of chromosomal instability of MMR-proficient familial CRC are clearly distinct from those from sporadic CRC. Both the increased gain on chromosome 20 and the increased levels of cnLOH suggest the presence of yet undiscovered germline defects that can, in part, underlie the cancer risk in these families.

Role of p38 and inducible nitric oxide synthase in the in vivo dopaminergic cells' degeneration induced by inflammatory processes after lipopolysaccharide injection.

Accumulating evidences suggest that neuroinflammation is involved in the progressive death of dopaminergic neurons in Parkinson's disease. Several studies have shown that intranigral injection of lipopolysaccharide induces inflammation in the substantia nigra leading to death of tyrosine hydroxylase-positive cells. To better understand how the inflammatory response gives rise to neurotoxicity we induced inflammation in substantia nigra by injecting lipopolysaccharide. The damage of substantia nigra dopaminergic neurons was evaluated by immunohistochemistry, reverse transcription-PCR and Western blot analysis of tyrosine hydroxylase. In parallel, activation of microglial cells, a hallmark of inflammation in CNS, was revealed by immunohistochemistry. Similarly the expression of molecules involved in the inflammatory response and apoptotic pathway was also tested, such as cytokines (tumor necrosis factor-alpha, interleukin-1beta, interleukin-6), inducible nitric oxide synthase and caspase-11. Tyrosine hydroxylase expression (both mRNA and protein) started to decrease around 3 days post-injection. At the mRNA level, our results showed that the cytokines expression peaked shortly (3-6 h) after lipopolysaccharide injection, followed by the induction of inducible nitric oxide synthase and caspase-11 (14 h). However, inducible nitric oxide synthase protein peaked at 24 h and lasted for 14 days. The lipopolysaccharide-induced loss of substantia nigra dopaminergic neurons was partially inhibited by co-injection of lipopolysaccharide with S-methylisothiourea, an inducible nitric oxide synthase inhibitor. Co-injections of lipopolysaccharide with SB203580, a p38 MAP kinase inhibitor, reduced inducible nitric oxide synthase and caspase-11 mRNA expression, and also rescued dopaminergic neurons in substantia nigra. In summary, this is the first report to describe in vivo the temporal profile of the expression of these inflammatory mediators and proteins involved in dopaminergic neuronal death after intranigral injection of lipopolysaccharide. Moreover data strongly support that lipopolysaccharide-induced dopaminergic cellular death in substantia nigra could be mediated, at least in part, by the p38 signal pathway leading to activation of inducible nitric oxide synthase and caspase-11.

La hepatitis aguda puede formar parte de la escarlatina / Acute hepatitis may form part of scarlet fever

No disponible

A comparative study of Bowman's layer in some mammals: Relationships with other constituent corneal structures / Estudio comparado de la capa de Bowman en algunos mamíferos: relación con otras estructuras constituyentes de la córnea

Existing morphological and morphometric studies of mammalian cornea offer little information about the morphology and morphometry of Bowman's layer. Furthermore, no data regarding the relationship between Bowman's layer and other corneal structures are currently available. It is for this reason that we have decided to carry out a comparative study of the main features of Bowman's layer in 40 species of mammals (carnivores, primates and herbivores) and to determine its relationship with other corneal layers. The results pointed out the existence of Bowman's layer in nearly all the primates studied. The only exception was the lemur (Lepilemur mustelinus). Bowman's layer was absent in all the carnivores in the study but was present in some herbivores (deer, sambar deer, giraffe, ox, zebu and eland). In addition, there appears to be a certain relationship between the presence of Bowman's layer and the thickness of the epithelium and Descemet's membrane (AU)

Los estudios morfológicos y morfométricos existentes sobre la córnea de los mamíferos ofrecen poca información acerca de la morfología y la morfometría de la capa de Bowman. Tampoco se dispone de datos en los que se relacione a la capa de Bowman con el resto de las estructuras corneales. Por todo ello, se ha decidido realizar un estudio comparativo de las principales características de la capa de Bowman en 40 especies de mamíferos (carnívoros, primates y herbívoros). Así mismo, se han buscado las posibles relaciones existentes entre la capa de Bowman y el resto de estructuras formadoras de la córnea. Los resultados obtenidos indican la existencia de capa de Bowman en las córneas de todos los primates estudiados, con la única excepción de la córnea del lemur (Lepilemur mustelinus). No se ha detectado la presencia de capa de Bowman en ninguno de los carnívoros, y sí se ha podido establecer su existencia en algunos de los herbívoros estudiados (ciervo común, ciervo de zambra, jirafa, buey, zebu y antílope eland). Finalmente, se ha establecido la existencia de cierta relación entre la presencia de capa de Bowman y el espesor del epitelio y de la membrana de Descemet corneales (AU)

Obstruction of trabecular orifices in primary open-angle glaucoma / Obstrucción de los orificios trabeculares en el glaucoma primario de ángulo abierto

The morphologic and structural changes undergone by the trabecular meshwork have frequently been related to the development of primary open-angle glaucoma, which consists of a sustained increase in intraocular pressure due to the accumulation of aqueous humour in the anterior chamber of the eye. The aqueous humour leaves the anterior chamber of the eye, passing through the trabecular orifices to Schlemm's canal. Accordingly, the anatomic integrity of the trabecular meshwork is necessary to guarantee correct aqueous drainage and the maintenence of adequate intraocular pressure. In the present study, the three-dimensional morphology of glaucomatous trabecular meshworks was studied with a view to observing morphological changes possibly related to the development of primary open angle-glaucoma (AU)

Los cambios morfológicos y estructurales de la malla trabecular han sido frecuentemente relacionados con la instauración de un glaucoma primario de ángulo abierto, consistente en un incremento mantenido de la presión intraocular secundario a la acumulación de humor acuoso en la cámara anterior del ojo. El humor acuoso abandona la cámara anterior del ojo pasando a través de los orificios trabeculares hacia el conducto de Schlemm. Por tanto, la integridad anatómica de la malla trabecular es necesaria para garantizar su correcto drenaje así como el mantenimiento de una presión intraocular adecuada. En el presente estudio, hemos estudiado la morfología tridimensional de mallas trabeculares glaucomatosas con la intención de observar cambios morfológicos que se puedan relacionar con el desarrollo de un glaucoma primario de ángulo abierto (AU)

Rapid PCR-mediated synthesis of competitor molecules for accurate quantification of beta(2) GABA(A) receptor subunit mRNA.

We describe a fast and easy method for the synthesis of competitor molecules based on non-specific conditions of PCR. RT-competitive PCR is a sensitive technique that allows quantification of very low quantities of mRNA molecules in small tissue samples. This technique is based on the competition established between the native and standard templates for nucleotides, primers or other factors during PCR. Thus, the most critical parameter is the use of good internal standards to generate a standard curve from which the amount of native sequences can be properly estimated. At the present time different types of internal standards and methods for their synthesis have been described. Normally, most of these methods are time-consuming and require the use of different sets of primers, different rounds of PCR or specific modifications, such as site-directed mutagenesis, that need subsequent analysis of the PCR products. Using our method, we obtained in a single round of PCR and with the same primer pair, competitor molecules that were successfully used in RT-competitive PCR experiments. The principal advantage of this method is high versatility and economy. Theoretically it is possible to synthesize a specific competitor molecule for each primer pair used. Finally, using this method we have been able to quantify the increase in the expression of the beta(2) GABA(A) receptor subunit mRNA that occurs during rat hippocampus development.

Prevalence between different alpha subunits performing the benzodiazepine binding sites in native heterologous GABA(A) receptors containing the alpha2 subunit.

The presence of two heterologous alpha subunits and a single benzodiazepine binding site in the GABA(A) receptor implicates the existence of pharmacologically active and inactive alpha subunits. This fact raises the question of whether a particular alpha subtype could predominate performing the benzodiazepine binding site. The hippocampal formation expresses high levels of alpha subunits with different benzodiazepine binding properties (alpha1, alpha2 and alpha5). Thus, we first demonstrated the existence of alpha2-alpha1 (36.3 +/- 5.2% of the alpha2 population) and alpha2-alpha5 (20.2 +/- 2.1%) heterologous receptors. A similar alpha2-alpha1 association was observed in cortex. This association allows the direct comparison of the pharmacological properties of heterologous native GABA(A) receptors containing a common (alpha2) and a different (alpha1 or alpha5) alpha subunit. The alpha2 subunit pharmacologically prevailed over the alpha1 subunit in both cortex and hippocampus (there was an absence of high-affinity binding sites for Cl218,872, zolpidem and [3H]zolpidem). This prevalence was directly probed by zolpidem displacement experiments in alpha2-alpha1 double immunopurified receptors (K(i) = 295 +/- 56 nM and 200 +/- 8 nM in hippocampus and cortex, respectively). On the contrary, the alpha5 subunit pharmacologically prevailed over the alpha2 subunit (low- and high-affinity binding sites for zolpidem and [3H]L-655,708, respectively). This prevalence was probed in alpha2-alpha5 double immunopurified receptors. Zolpidem displayed a single low-affinity binding site (K(i) = 1.73 +/- 0.54 microM). These results demonstrated the existence of a differential dominance between the different alpha subunits performing the benzodiazepine binding sites in the native GABA(A) receptors.

Ultrastructural changes of the extracellular matrix of the trabecular meshwork with age / Cambios ultraestructurales en la matriz extracelular de la red trabecular con la edad

The morphology of the extracellular matrix was studied in a series of human trabecular meshworks obtained from specimens of different ages without any known ocular pathology. Our aim was to identify ultrastructural changes related to an increase in intraocular pressure with aging. 24 trabecular meshworks obtained from individuals with ages ranging from 23 to 99 were specifically prepared for subsequent transmission electron microscopic observation using standard techniques. Our results show that the extracellular matrix of the trabecular beams undergoes progressive changes with increasing age in all its components (collagen fibres, elastin-like plaques and basal membrane). These changes may be related to an increase in intraocular pressure since they can alter the aqueous outflow from the anterior chamber to Schlemm's canal and can interfere with the drainage, facilitating mechanism of the ciliary muscle (AU)

Se estudió la morfología de la matriz extracellular en unas series de redes trabeculares humanas obtenidas de ejemplares de distintas edades sin ninguna patología ocular conocida. Nuestro objetivo era intentar identificar los cambios ultraestructurales relacionados con un aumento de la presión intraocular con el envejecimiento. Se prepararon específicamente 24 redes trabeculares obtenidas de individuos con edades comprendidas entre los 23 y los 99 años para su observación subsiguiente con microscopía electrónica de transmisión, utilizándose las técnicas habituales. Los resultados obtenidos muestran que la matriz extracelular de las haces trabeculares sufre cambios progresivos con el envejecimiento en todos sus compartimentos (fibras de colágeno, placas de tipo elastina y membrana basal). Es posible que estos cambios estén relacionados con un aumento en la presión intraocular, puesto que son capaces de alterar la producción acuosa desde la cámara anterior hacia el canal de Schlemm y pueden interferir con el mecanismo facilitador de drenaje del músculo ciliar (AU)

Subunit composition of rat ventral spinal cord GABA(A) receptors, assessed by single cell RT-multiplex PCR.

We analyzed the expression of native GABA(A) receptors in choline acetyltransferase and glutamic acid decarboxilase positive cells, from lamina IX of the lumbar region of rat spinal cord. More than one isoform of each subunit was detected within a single cell. The alpha3, alpha5, alpha1, beta3 and gamma2 subunit was the most frequent combination in both cell populations. However, the total number of subunit expressed by each cell type was different, being the ChAT positive cells the simplest. Interestingly, the ChAT and GAD positive cells also displayed a different pattern of distribution of both spliced isoforms of the gamma2 subunit. These results indicate that several GABA(A) receptors, with different molecular composition, are expressed in a single cell and that different cell types can express different GABA(A) receptors.