Discrimination of motor and sensorimotor effects of phencyclidine and MK-801: Involvement of GluN2C-containing NMDA receptors in psychosis-like models.

Non-competitive NMDA receptor (NMDA-R) antagonists like ketamine, phencyclidine (PCP) and MK-801 are routinely used as pharmacological models of schizophrenia. However, the NMDA-R subtypes, neuronal types (e.g., GABA vs. glutamatergic neurons) and brain regions involved in psychotomimetic actions are not fully understood. PCP activates thalamo-cortical circuits after NMDA-R blockade in reticular thalamic GABAergic neurons. GluN2C subunits are densely expressed in thalamus and cerebellum. Therefore, we examined their involvement in the behavioral and functional effects elicited by PCP and MK-801 using GluN2C knockout (GluN2CKO) and wild-type mice, under the working hypothesis that psychotomimetic effects should be attenuated in mutant mice. PCP and MK-801 induced a disorganized and meandered hyperlocomotion in both genotypes. Interestingly, stereotyped behaviors like circling/rotation, rearings and ataxia signs were dramatically reduced in GluN2CKO mice, indicating a better motor coordination in absence of GluN2C subunits. In contrast, other motor or sensorimotor (pre-pulse inhibition of the startle response) aspects of the behavioral syndrome remained unaltered by GluN2C deletion. PCP and MK-801 evoked a general pattern of c-fos activation in mouse brain (including thalamo-cortical networks) but not in the cerebellum, where they markedly reduced c-fos expression, with significant genotype differences paralleling those in motor coordination. Finally, resting-state fMRI showed an enhanced cortico-thalamic-cerebellar connectivity in GluN2CKO mice, less affected by MK-801 than controls. Hence, the GluN2C subunit allows the dissection of the behavioral alterations induced by PCP and MK-801, showing that some motor effects (in particular, motor incoordination), but not deficits in sensorimotor gating, likely depend on GluN2C-containing NMDA-R blockade in cerebellar circuits.

Identification of BiP as a CB1 Receptor-Interacting Protein That Fine-Tunes Cannabinoid Signaling in the Mouse Brain.

Cannabinoids, the bioactive constituents of cannabis, exert a wide array of effects on the brain by engaging Type 1 cannabinoid receptor (CB1R). Accruing evidence supports that cannabinoid action relies on context-dependent factors, such as the biological characteristics of the target cell, suggesting that cell population-intrinsic molecular cues modulate CB1R-dependent signaling. Here, by using a yeast two-hybrid-based high-throughput screening, we identified BiP as a potential CB1R-interacting protein. We next found that CB1R and BiP interact specifically in vitro, and mapped the interaction site within the CB1R C-terminal (intracellular) domain and the BiP C-terminal (substrate-binding) domain-α. BiP selectively shaped agonist-evoked CB1R signaling by blocking an "alternative" Gq/11 protein-dependent signaling module while leaving the "classical" Gi/o protein-dependent inhibition of the cAMP pathway unaffected. In situ proximity ligation assays conducted on brain samples from various genetic mouse models of conditional loss or gain of CB1R expression allowed to map CB1R-BiP complexes selectively on terminals of GABAergic neurons. Behavioral studies using cannabinoid-treated male BiP+/- mice supported that CB1R-BiP complexes modulate cannabinoid-evoked anxiety, one of the most frequent undesired effects of cannabis. Together, by identifying BiP as a CB1R-interacting protein that controls receptor function in a signaling pathway- and neuron population-selective manner, our findings may help to understand the striking context-dependent actions of cannabis in the brain.SIGNIFICANCE STATEMENT Cannabis use is increasing worldwide, so innovative studies aimed to understand its complex mechanism of neurobiological action are warranted. Here, we found that cannabinoid CB1 receptor (CB1R), the primary molecular target of the bioactive constituents of cannabis, interacts specifically with an intracellular protein called BiP. The interaction between CB1R and BiP occurs selectively on terminals of GABAergic (inhibitory) neurons, and induces a remarkable shift in the CB1R-associated signaling profile. Behavioral studies conducted in mice support that CB1R-BiP complexes act as fine-tuners of anxiety, one of the most frequent undesired effects of cannabis use. Our findings open a new conceptual framework to understand the striking context-dependent pharmacological actions of cannabis in the brain.

Psychological impact of multigene cancer panel testing in patients with a clinical suspicion of hereditary cancer across Spain.

OBJECTIVE: Patients' psychological reactions to multigene cancer panel testing might differ compared with the single-gene testing reactions because of the complexity and uncertainty associated with the different possible results. Understanding patients' preferences and psychological impact of multigene panel testing is important to adapt the genetic counselling model. METHODS: One hundred eighty-seven unrelated patients with clinical suspicion of hereditary cancer undergoing a 25-gene panel test completed questionnaires after pretest genetic counselling and at 1 week, 3 months, and 12 months after results to elicit their preferences regarding results disclosure and to measure their cancer worry and testing-specific distress and uncertainty. RESULTS: A pathogenic variant was identified in 38 patients (34 high penetrance and 4 moderate penetrance variants), and 54 patients had at least one variant of uncertain significance. Overall, cancer panel testing was not associated with an increase in cancer worry after results disclosure (P value = .87). Twelve months after results, carriers of a moderate penetrance variant had higher distress and uncertainty scores compared with carriers of high penetrance variants. Cancer worry prior to genetic testing predicted genetic testing specific distress after results, especially at long term (P value <.001). Most of the patients reported the wish to know all genetic results. CONCLUSIONS: Our results suggest that patients can psychologically cope with cancer panel testing, but distress and uncertainty observed in carriers of moderate penetrance cancer variants in this cohort warrant further research.

Weekday and weekend food advertising varies on children's television in the USA but persuasive techniques and unhealthy items still dominate.

OBJECTIVE: In 2006, food industry self-regulatory efforts aimed to balance the mix of food advertisements to limit children's exposure to unhealthy food products. An update to these efforts proposed to eliminate all unhealthy advertisements during peak child viewing times and implement uniform nutrition criteria by December, 2013. Marketing techniques are not currently addressed in self-regulatory efforts. The food industry's pledge prompted researchers to conduct a content analysis to assess nutritional quality and presence of persuasive marketing techniques in child-directed food and beverage advertisements. STUDY DESIGN: Content analysis. METHODS: 32 h of children's television programming were recorded in February, 2013. Three independent coders assessed the nutritional content of food and beverage advertisements using the UK Nutrition Profiling System and assessed presence of persuasive techniques (PTs) using a rating form developed for this study. RESULTS: Overall, 13.75% of advertisements promoted a food or beverage product. Most food advertisements, 54.6%, represented unhealthy products and 95.48% of food advertisements contained at least one PT. The number of PTs was not significantly different for healthy (M = 4.98, SD = 2.07) and unhealthy food advertisements (M = 4.66, SD = 1.82) however food advertisements aimed at children used significantly more PTs (M = 5.5, SD = 1.43) than those targeting adults (M = 1.52, SD = 1.54), t (153) = 11.738, P < 0.0001. Saturday morning children's programming showed significantly fewer food advertisements compared to weekday morning children's programming. CONCLUSIONS: While a majority of food-related advertisements represented unhealthy items, advertisements airing during Saturday morning programming featured fewer food advertisements overall and were more frequently for healthier items compared to weekdays. Industry self-regulation may not be effective for reducing overall unhealthy ad exposure but may play a role in reduced exposure on weekends. Despite policy efforts, additional changes are needed to improve ad exposure experienced by children with a focus on addressing the persistent use of persuasive marketing techniques in food advertising intended for children.

Visualization of 5-HT Receptors Using Radioligand-Binding Autoradiography.

Described in this unit are techniques to visualize the majority of serotonin (5-hydroxytryptamine, 5-HT) receptor subtypes in sections of frozen brain tissue using receptor autoradiography. Protocols for brain extraction and sectioning, radioligand exposure, autoradiogram generation, and data quantification are provided, as are the optimal incubation conditions for the autoradiographic visualization of receptors using agonist and antagonist radioligands. © 2016 by John Wiley & Sons, Inc.

Serotonin 5-HT4 receptors and forebrain cholinergic system: receptor expression in identified cell populations.

Activation of serotonin 5-HT4 receptors has pro-cognitive effects on memory performance. The proposed underlying neurochemical mechanism is the enhancement of acetylcholine release in frontal cortex and hippocampus elicited by 5-HT4 agonists. Although 5-HT4 receptors are present in brain areas related to cognition, e.g., hippocampus and cortex, the cellular localization of the receptors that might modulate acetylcholine release is unknown at present. We have analyzed, using dual label in situ hybridization, the cellular localization of 5-HT4 receptor mRNA in identified neuronal populations of the rat basal forebrain, which is the source of the cholinergic innervation to cortex and hippocampus. 5-HT4 receptor mRNA was visualized with isotopically labeled oligonucleotide probes, whereas cholinergic, glutamatergic, GABAergic and parvalbumin-synthesizing neurons were identified with digoxigenin-labeled oligonucleotide probes. 5-HT4 receptor mRNA was not detected in the basal forebrain cholinergic cell population. In contrast, basal forebrain GABAergic, parvalbumin synthesizing, and glutamatergic cells contained 5-HT4 receptor mRNA. Hippocampal and cortical glutamatergic neurons also express this receptor. These results indicate that 5-HT4 receptors are not synthesized by cholinergic cells, and thus would be absent from cholinergic terminals. In contrast, several non-cholinergic cell populations within the basal forebrain and its target hippocampal and cortical areas express these receptors and are thus likely to mediate the enhancement of acetylcholine release elicited by 5-HT4 agonists.

Tratamiento precoz de vasculitis idiopática, aneurismas y retinitis (IRVAN). A propósito de un caso / Early treatment of idiopathic vasculitis, aneurysms and neuroretinitis (IRVAN). A case report

CASO CLÍNICO: Se presenta el caso de una mujer de 55 años con vasculitis retiniana, aneurismas arteriales múltiples en el polo posterior, exudación macular e hipoperfusión periférica bilateral (IRVAN) tratada precozmente con panfotocoagulación periférica. Tras 3 años de seguimiento la agudeza visual permanece estable y no hay progresión de la isquemia. DISCUSIÓN: El síndrome de IRVAN con neovascularización es difícil de controlar y el riesgo de progresión a glaucoma neovascular, a pesar del tratamiento, es alto. La panfotocoagulación en estadios iniciales es eficaz para controlar la isquemia y debe realizarse lo antes posible

CASE REPORT: A 55 year old woman presented with retinal vasculitis, multiple aneurysms, macular exudation and widespread retinal nonperfusion and was diagnosed with IRVAN. She was treated with panretinal laser photocoagulation. After 3 years of follow up visual acuity remains stable and there are no complications due to ischaemic sequelae. DISCUSSION: IRVAN syndrome with neovascularisation can progress rapidly despite laser treatment. Panretinal laser photocoagulation has to be considered in the early stages as it is effective in stopping the progression of ischaemia

[Early treatment of idiopathic vasculitis, aneurysms and neuroretinitis (IRVAN). A case report]. / Tratamiento precoz de vasculitis idiopática, aneurismas y retinitis (IRVAN). A propósito de un caso.

CASE REPORT: A 55 year old woman presented with retinal vasculitis, multiple aneurysms, macular exudation and widespread retinal nonperfusion and was diagnosed with IRVAN. She was treated with panretinal laser photocoagulation. After 3 years of follow up visual acuity remains stable and there are no complications due to ischaemic sequelae. DISCUSSION: IRVAN syndrome with neovascularisation can progress rapidly despite laser treatment. Panretinal laser photocoagulation has to be considered in the early stages as it is effective in stopping the progression of ischaemia.

Multiple conformations of 5-HT2A and 5-HT 2C receptors in rat brain: an autoradiographic study with [125I](±)DOI.

Earlier autoradiographic studies with the 5-HT2 receptor agonist [(125)I](±)DOI in human brain showed unexpected biphasic competition curves for various 5-HT2A antagonists. We have performed similar studies in rat brain regions with selective 5-HT2A (M100907) and 5-HT2C (SB242084) antagonists together with ketanserin and mesulergine. The effect of GTP analogues on antagonist competition was also studied. Increasing concentrations of Gpp(NH)p or GTPγS resulted in a maximal inhibition of [(125)I](±)DOI-specific binding of approximately 50 %. M100907 competed biphasically in all regions. In the presence of 100 µM Gpp(NH)p, M100907 still displaced biphasically the remaining [(125)I](±)DOI binding. Ketanserin showed biphasic curves in some regions and monophasic curves in others. In the latter, Gpp(NH)p evidenced an additional high-affinity site. SB242084 competed biphasically in brainstem nuclei and monophasically in the other regions. In most areas, SB242084 affinities were not notably altered by Gpp(NH)p. Mesulergine competed monophasically in all regions without alteration by Gpp(NH)p. These results conform with the extended ternary complex model of receptor action: receptor exists as an equilibrium of multiple conformations, i.e. ground (R), partly activated (R*) and activated G-protein-coupled (R*G) conformation/s. Thus, [(125)I](±)DOI would label multiple conformations of both 5-HT2A and 5-HT2C receptors in rat brain, and M100907 and ketanserin would recognise these conformations with different affinities.

Lipopolysaccharide administration in vivo induces differential expression of cAMP-specific phosphodiesterase 4B mRNA splice variants in the mouse brain.

Many inflammatory processes involve cAMP. Pharmacological manipulation of cAMP levels using specific phosphodiesterase (PDE) inhibitors provokes an antiinflammatory response. The aim of this study was to investigate changes in the pattern and levels of expression of mRNAs coding for the cAMP-specific PDE4 family and subfamilies in mouse brain during the immediate acute immune response provoked by an intraperitoneal injection of lipopolysaccharide (LPS). PDE4B, and furthermore the splice variants PDE4B2 and PDE4B3, were the only mRNAs that showed altered expression. Whereas PDE4B2 presented increased expression at both 3 and 8 hr postinjection, PDE4B3 mRNA showed decreased expression that reached a minimum 8 hr postinjection. PDE4B2 mRNA upregulation was observed mainly in endothelial and macrophage/neutrophil cell populations in the leptomeninges, and the downregulation of PDE4B3 was observed mainly in oligodendrocytes throughout the brain. Our results clearly illustrate the distinctive anatomical distribution and cellular localization of the PDE4Bs during neuroinflammation and emphasize the importance of PDE4B splice-variant-specific inhibitors as therapeutic tools.

Colitis por citomegalovirus / No disponible

No disponible

Reduced signal transduction by 5-HT4 receptors after long-term venlafaxine treatment in rats.

BACKGROUND AND PURPOSE: The 5-HT(4) receptor may be a target for antidepressant drugs. Here we have examined the effects of the dual antidepressant, venlafaxine, on 5-HT(4) receptor-mediated signalling events. EXPERIMENTAL APPROACH: The effects of 21 days treatment (p.o.) with high (40 mg·kg(-1)) and low (10 mg·kg(-1)) doses of venlafaxine, were evaluated at different levels of 5-HT(4) receptor-mediated neurotransmission by using in situ hybridization, receptor autoradiography, adenylate cyclase assays and electrophysiological recordings in rat brain. The selective noradrenaline reuptake inhibitor, reboxetine (10 mg·kg(-1), 21 days) was also evaluated on 5-HT(4) receptor density. KEY RESULTS: Treatment with a high dose (40 mg·kg(-1)) of venlafaxine did not alter 5-HT(4) mRNA expression, but decreased the density of 5-HT(4) receptors in caudate-putamen (% reduction = 26 ± 6), hippocampus (% reduction = 39 ± 7 and 39 ± 8 for CA1 and CA3 respectively) and substantia nigra (% reduction = 49 ± 5). Zacopride-stimulated adenylate cyclase activation was unaltered following low-dose treatment (10 mg·kg(-1)) while it was attenuated in rats treated with 40 mg·kg(-1) of venlafaxine (% reduction = 51 ± 2). Furthermore, the amplitude of population spike in pyramidal cells of CA1 of hippocampus induced by zacopride was significantly attenuated in rats receiving either dose of venlafaxine. Chronic reboxetine did not modify 5-HT(4) receptor density. CONCLUSIONS AND IMPLICATIONS: Our data indicate a functional desensitization of 5-HT(4) receptors after chronic venlafaxine, similar to that observed after treatment with the classical selective inhibitors of 5-HT reuptake.

Serotonin 4 receptor (5-HT4R) internalization is isoform-specific: effects of 5-HT and RS67333 on isoforms A and B.

Serotonin 4 receptors (5-HT4Rs) are particularly abundant within the limbic system, where they constitute potential targets for the development of novel, rapid acting antidepressants. However, the population of limbic 5-HT4Rs is not homogenous, comprising various isoforms of which 5-HT4(a) and 5-HT4(b) are among the most abundant variants. Sequence divergence at their C-termini is predictive of specificity in isoform signalling and regulation, but the differences, if any, remain ill-defined. The present study compared isoforms 5-HT4(a) and 5-HT4(b) in their ability to undergo endocytic regulation following exposure to 5-HT and to the putatively fast acting antidepressant RS67333. Both ligands differed in their ability to induce internalization of either isoform, 5-HT being more effective than RS67333 in HEK293 cells and in neurons. In contrast, trafficking induced by 5-HT was isoform-specific. In particular, while PKC, GRK2 and betaarrestin were necessary for 5-HT4(a)R internalization, sequestration of 5-HT4(b)Rs required PKC but not GRK2 and relied significantly less on betaarrestin. After endocytosis, isoform (b) appeared scattered throughout the intracellular compartment and efficiently recycled to the membrane upon agonist removal. Isoform (a) accumulated in the perinuclear compartment and displayed little recycling. Isoform-specific subcellular distribution was present in HEK293 cells and in neurons. In neurons, where internalization by RS67333 was more pronounced than in HEK293 cells, receptors internalized by this ligand followed the same distribution pattern as observed with 5-HT. These results point to isoform-related differences in the way that 5-HTRs respond to different ligands. Such diversity should be taken into account when developing therapeutic agents that target 5-HT4Rs.

Morphine desensitization, internalization, and down-regulation of the mu opioid receptor is facilitated by serotonin 5-hydroxytryptamine2A receptor coactivation.

Analysis of the distribution of mRNA encoding the serotonin (5-hydroxytryptamine) 5-HT(2A) receptor and the mu opioid peptide receptor in rat brain demonstrated their coexpression in neurons in several distinct regions. These regions included the periaqueductal gray, an area that plays an important role in morphine-induced analgesia but also in the development of tolerance to morphine. To explore potential cross-regulation between these G protein-coupled receptors, the human mu opioid peptide receptor was expressed stably and constitutively in Flp-In T-REx human embryonic kidney 293 cells that harbored the human 5-HT(2A) receptor at the inducible Flp-In locus. In the absence of the 5-HT(2A) receptor, pretreatment with the enkephalin agonist [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin but not with the alkaloid agonist morphine produced desensitization, internalization, and down-regulation of the mu opioid peptide receptor. Induction of 5-HT(2A) receptor expression in these cells resulted in up-regulation of mu opioid peptide receptor levels that was blocked by both a 5-HT(2A) receptor inverse agonist and selective inhibition of signaling via Galpha(q)/Galpha(11) G proteins. After induction of the 5-HT(2A) receptor, coaddition of 5-HT with morphine now also resulted in desensitization, receptor internalization, and down-regulation of the mu opioid peptide receptor. It has been argued that enhancement of mu opioid peptide receptor internalization in response to morphine would limit the development of tolerance without limiting analgesia. These data suggest that selective activation of the 5-HT(2A) receptor in concert with treatment with morphine might achieve this aim.

[Systemic AA amyloidosis induced by benign neoplasms]. / Amiloidosis secundaria (AA) asociada a tumoraciones benignas.

Amyloidosis is a systemic disorder characterized by the extracellular tissue deposition of insoluble, toxic aggregates in bundles of beta-sheet fibrillar proteins. These deposits are typically identified on the bases of their apple-green birrefringence under a polarized light microscope after staining with Congo red, and by the presence of rigid, nonbranching fibrils 8 to 10 nm in diameter on electron microscopy. The type of amyloid fibril unit can be further defined by immunohistology or by immunoelectron microscopy. It has been described at least 25 different human protein precursors of amyloid fibrils, which will describe its corresponding amyloid disease. The most common types of amyloidosis are AL (primary) and AA (secondary) types; the former, is the most frequent and is due to deposition of proteins derived from immunoglobulin light chain fragments, occurring alone or in association with multiple myeloma. The later (AA), is caused by deposition of fibrils composed of fragments of the acute phase reactant serum amyloid A (SAA) and complicates chronic diseases with ongoing or recurring inflammation, namely; rheumatoid arthritis (RA), juvenile chronic polyarthritis, ankylosing spondylitis, familial periodic fever syndromes (Familial Mediterranean Fever), chronic infections and furthermore, some neoplasms (mainly renal cell carcinoma and Hodgkin's disease). Despite its less frequent association, some benign neoplasms can subsequently complicate to AA amyloidosis, therefore, an early diagnose and successful treatment may lead indeed, to regression of the amyloid disease. Herein, we present two cases of AA amyloidosis, both of them caused by 2 different benign neoplasms: 1. A 34 year-old woman, after chronic oral contraceptive use, developed an hepatic adenoma (fig. 1) which finally lead to AA amyloidosis with primary kidney presentation (pure nephrotic syndrome) (table 1). Post-surgical complications yield to acute renal failure from which unfortunately could not be recovered. After being on hemodialysis therapy during 10 months she received a first renal allograft without any complication. 2. A 20 year old woman, was diagnosed of AA amyloidosis after a renal biopsy (fig. 2) because of nephrotic syndrome (table 1). Further investigation lead to the finding of a hialyne-vascular type Castleman's disease located in the retroperitoneum (fig. 2). Despite surgical resection and medical treatment (colchicine) she developed progressive renal failure requiring initialization of hemodialysis therapy. After 6 years being on hemodialysis, she received a first renal allograft which is currently functioning after one year of follow- up. Although other chronic inflammatory diseases complicate more frequently to AA amyloidosis, benign tumors have to be taken into account as a potential ethiological cause for secondary amyloidosis.

Amiloidosis secundaria (AA) asociada a tumoraciones benignas / Systemic AA amyloidosis induced by benign neoplasms

La amiloidosis se caracteriza por el depósito de proteínas de características ultraestructurales fibrilares, con plegamiento Beta en capas e insolubles, que se depositan mayoritariamente a nivel de los espacios extracelulares de órganos y tejidos. Se clasifica típicamente según la naturaleza bioquímica de la proteína fibrilar, y según su distribución en el organismo podrá ser sistémica o localizada. La amiloidosis sistémica más frecuente en la práctica clínica es la denominada AL (idiopática primaria o asociada a mieloma múltiple) cuyas fibrillas están formadas por cadenas ligeras. En cambio, la amiloidosis AA (secundaria, reactiva o adquirida) es aquella que se desarrolla típicamente como complicación de una enfermedad inflamatoria crónica, destacando entre las más habituales; enfermedades de origen reumatológico (artritis reumatoide, espondilitis anquilopoyética, artritis psoriásica), la fiebre mediterránea familiar, la enfermedad inflamatoria intestinal, así como infecciones cronificadas (tuberculosis, osteomielitis). No obstante, otras causas responsables de su desarrollo y en muchas ocasiones infravaloradas, son las tumoraciones benignas. Algunas de estas entidades, también tendrán capacidad de actuar como estímulo responsable de la formación de estas proteínas, que finalmente se depositarán en diferentes tejidos del organismo. Es importante resaltar, que el diagnóstico precoz así como el tratamiento eficaz de la enfermedad subyacente ha permitido disminuir su incidencia, así como en algunos casos incluso revertirla. Aquí, presentamos dos casos clínicos paradigmáticos de tumoraciones benignas, adenoma hepático y Enfermedad de Castlemann, que desarrollaron posteriormente amiloidosis AA con afectación renal principalmente en forma de síndrome Nefrótico (AU)

Amyolidosis is a systemic disorder characterized by the extracellular tissue deposition of insoluble, toxic aggregates in bundles of Beta-sheet fibrillar proteins. These deposits are typically identified on the bases of their apple-green birrefringence under a polarized light microscope after staining with Congo red, and by the presence of rigid, non branching fibrils 8 to 10 nm in diameter on electron microscopy. The type of amyloid fibril unit can be further defined by immunohistology or by immunoelectron microscopy. It has been described at least 25 different human protein precursors of amyloid fibrils, which will describe its corresponding amyloid disease. The most common types of amyloidosis are AL (primary) and AA (secondary) types; the former, is the most frequent and is due to deposition of proteins derived from immunoglobulin light chain fragments, occurring alone or in association with multiple myeloma. The later (AA), is caused by deposition of fibrils composed of fragments of the acute phase reactant serum amyloid A (SAA) and complicates chronic diseases with ongoing or recurring inflammation, namely; rheumatoid arthritis (RA), juvenile chronic polyarthritis, ankylosing spondylitis, familial periodic fever syndromes (Familial Mediterranean Fever), chronic infections and furthermore, some neoplasms (mainly renal cell carcinoma and Hodking¿s disease). Despite its less frequent association, some benign neoplasms can subsequently complicate to AA amyloidosis, therefore, an early diagnose and successful treatment may lead indeed, to regression of the amyloid disease. Herein, we present two cases of AA amyloidosis, both of them caused by 2 different benign neoplasms: 1. A 34 year-old woman, after chronic oral contraceptive use, developed an hepatic adenoma (fig. 1) which finally lead to AA amyloidosis with primary kidney presentation (pure nephrotic syndrome) (table 1). Post-surgical complications yield to acute renal failure from which unfortunately could not be recovered. After being on hemodialysis therapy during 10 months she received a first renal allograft without any complication. 2. A 20 yearold woman, was diagnosed of AA amyloidosis after a renal biopsy (fig. 2) because of nephrotic syndrome (table 1). Further investigation lead to the finding of a hialyne-vascular type Castleman¿s disease located in the retroperotoneum (fig. 2). Despite surgical resection and medical treatment (colchicine) she developed progressive renal failure requiring initialization of hemodialysis therapy. After 6 years being on hemodialysis, she received a first renal allograft which is currently functioning after one year of follow- up. Although other chronic inflamatory diseases complicate more frequently to AA amyloidosis, benign tumors have to be taken into account as a potential ethiological cause for secondary amyloidosis (AU)

Long-term exposure to dieldrin reduces gamma-aminobutyric acid type A and N-methyl-D-aspartate receptor function in primary cultures of mouse cerebellar granule cells.

The organochlorine pesticide dieldrin is a persistent organic pollutant that accumulates in the fatty tissue of living organisms. In mammals, it antagonizes the GABA(A) receptor, producing convulsions after acute exposure. Although accumulation in human brain has been reported, little is known about the effects of long-term exposure to dieldrin in the nervous system. Homeostatic control of the balance between excitation and inhibition has been reported when neuronal activity is chronically altered. We hypothesized that noncytotoxic concentrations of dieldrin could decrease glutamatergic neurotransmission as a consequence of a prolonged reduction in GABA(A) receptor function. Long-term exposure of primary cerebellar granule cell cultures to 3 microM dieldrin reduced the GABA(A) receptor function to 55% of control, as measured by the GABA-induced (36)Cl(-) uptake. This exposure produced a significant reduction (approximately 35%) of the NMDA-induced increase in [Ca(2+)](i) and of the [(3)H]MK-801 binding, which was not accompanied by a reduction in the NMDA receptor subunit NR1, as determined by Western blot. Consistent with the decreased NMDA receptor function, dieldrin-treated cultures were insensitive to an excitotoxic stimulus induced by exposure to high potassium. In summary, we report that the chronic reduction of GABA(A) receptor function induced by dieldrin decreases the number of functional NMDA receptors, which may be attributable to a mechanism of synaptic scaling. These effects could underlie neural mechanisms involved in cognitive impairment produced by low-level exposure to dieldrin.

Rat Schwann cells express M1-M4 muscarinic receptor subtypes.

The expression of different muscarinic receptor subtypes was analyzed in immature Schwann cells obtained from sciatic nerve of 2-day neonatal rats. By using RT-PCR analysis, we demonstrated the presence of M1, M2, M3, and M4 receptor subtypes in cultured Schwann cells, with M2 displaying the highest expression levels. Muscarinic subtypes were also quantified by immunoprecipitation and [3H]QNB binding. With this approach, we found the levels of receptor expression to be M2 > M3 > M1. M4 is expressed at very low levels, and M5 receptor was not detectable. Moreover, we also demonstrated that stimulation of the receptors by muscarinic agonists activates previously described signal transduction pathways, leading to a decrease of cAMP and an increase of IP3 levels not associated with an efficient intracellular Ca2+ release. The presence and activity of particular muscarinic receptors in immature Schwann cells suggest that ACh may play an important role in Schwann cell development.

Serotonin 5-HT4 receptors and their mRNAs in rat and guinea pig brain: distribution and effects of neurotoxic lesions.

Serotonin 5-HT4 receptors are widely distributed in the periphery and in brain, where they modulate the release of various neurotransmitters and have been implicated in learning and memory. Nine C-terminal splice variants of this receptor have been cloned in mammalian species. In the rat, three such variants have been described: 5-HT4(a), 5-HT4(b), and 5-HT4(e). In the present study, we have examined several aspects of the distribution of these receptors in brain. First, we provide, in rat and guinea pig, a detailed comparison of the distribution of 5-HT4 receptors labeled by the antagonist [125I]-SB 207710 with the distribution of their encoding mRNA visualized by in situ hybridization histochemistry (ISHH). The results suggest that, in several projection systems (striato-nigral and striato-pallidal pathways, projection from dentate granule cells to field CA3, habenulo-interpeduncular pathway), 5-HT4 receptors are located both somatodendritically and axonally. Second, we have analyzed the distribution of mRNA for the three known rat splice variants by reverse transcription-polymerase chain reaction (RT-PCR) and by ISHH. RT-PCR indicates that all three variants are widely distributed, with 5-HT4(b) mRNA being present in all regions examined (olfactory tubercle, striatum, hippocampus, inferior colliculus, substantia nigra, parietal cortex) and 5-HT4(a) and 5-HT4(e) showing a somewhat more restricted distribution. In other regions (periaqueductal gray, reticular formation, medial septum, diagonal band), faint ISHH signals are observed for 5-HT4(a)+4(e) mRNAs, whereas 5-HT4(b) mRNA signals are almost undetectable. Finally, neurotoxic lesions of basal ganglia components in guinea pig also indicate a location of these receptors on terminals of striatal projection neurons.