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1.
Clin Transplant ; 38(3): e15285, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38516923

RESUMEN

Bloodstream infections (BSIs) account for 18% of bacterial infections in the first year after solid organ transplantation (SOT). Enterococcus accounts for up to 20% of BSIs in this population, with vancomycin-resistant enterococcus (VRE) posing a particular risk. This is a retrospective, case-control study of adult liver and kidney transplant recipients between 01/01/2016 and 06/30/2021 that characterizes the epidemiology and outcomes of enterococcal BSIs in liver and kidney transplantations at a single institution. Subjects with an enterococcal BSI within the first 6 months post-transplant were compared to those with non-enterococcal BSIs in the same period. We identified 26 subjects with enterococcal BSIs and 28 controls with non-enterococcal BSIs (n = 54; 10.3%). Cases were mostly liver transplant recipients (n = 20; 77%) with a median MELD at transplant of 33 (range 14-43); controls included 14 KT recipients (50%). Groups differed significantly (all p < .05) by factors including perioperative transfusion requirements, need for reoperation, and number of interventions post-transplant. Cases had a median time of 25.5 days to infection and controls 100.5 days (p < .0001). There were no differences in 1-year mortality between the groups. Enterococcus faecium was the predominant species of Enterococcus (n = 23; 88.5%), with a majority (91.3%) of the isolates being VRE. In our liver and kidney transplants, enterococcal BSIs occurred early among liver transplant recipients. The high incidence of VRE among E. faecium isolates in this population warrants further investigation into the optimal approach to empiric antimicrobials for bacteremia in the early post-transplant period.


Asunto(s)
Bacteriemia , Infecciones por Bacterias Grampositivas , Trasplante de Riñón , Enterococos Resistentes a la Vancomicina , Adulto , Humanos , Antibacterianos/uso terapéutico , Trasplante de Riñón/efectos adversos , Estudios Retrospectivos , Estudios de Casos y Controles , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Infecciones por Bacterias Grampositivas/epidemiología , Infecciones por Bacterias Grampositivas/etiología , Bacteriemia/etiología , Bacteriemia/microbiología , Hígado , Factores de Riesgo
2.
Clin Infect Dis ; 74(6): 965-972, 2022 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-34192322

RESUMEN

BACKGROUND: Antimicrobial stewardship (AS) programs are required by Centers for Medicare and Medicaid Services and should ideally have infectious diseases (ID) physician involvement; however, only 50% of ID fellowship programs have formal AS curricula. The Infectious Diseases Society of America (IDSA) formed a workgroup to develop a core AS curriculum for ID fellows. Here we study its impact. METHODS: ID program directors and fellows in 56 fellowship programs were surveyed regarding the content and effectiveness of their AS training before and after implementation of the IDSA curriculum. Fellows' knowledge was assessed using multiple-choice questions. Fellows completing their first year of fellowship were surveyed before curriculum implementation ("pre-curriculum") and compared to first-year fellows who complete the curriculum the following year ("post-curriculum"). RESULTS: Forty-nine (88%) program directors and 105 (67%) fellows completed the pre-curriculum surveys; 35 (64%) program directors and 79 (50%) fellows completed the post-curriculum surveys. Prior to IDSA curriculum implementation, only 51% of programs had a "formal" curriculum. After implementation, satisfaction with AS training increased among program directors (16% to 68%) and fellows (51% to 68%). Fellows' confidence increased in 7/10 AS content areas. Knowledge scores improved from a mean of 4.6 to 5.1 correct answers of 9 questions (P = .028). The major hurdle to curriculum implementation was time, both for formal teaching and for e-learning. CONCLUSIONS: Effective AS training is a critical component of ID fellowship training. The IDSA Core AS Curriculum can enhance AS training, increase fellow confidence, and improve overall satisfaction of fellows and program directors.


Asunto(s)
Programas de Optimización del Uso de los Antimicrobianos , Enfermedades Transmisibles , Anciano , Enfermedades Transmisibles/tratamiento farmacológico , Curriculum , Educación de Postgrado en Medicina , Becas , Humanos , Medicare , Encuestas y Cuestionarios , Estados Unidos
3.
Clin Infect Dis ; 73(5): 911-918, 2021 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-33730751

RESUMEN

Professional societies serve many functions that benefit constituents; however, few professional societies have undertaken the development and dissemination of formal, national curricula to train the future workforce while simultaneously addressing significant healthcare needs. The Infectious Diseases Society of America (IDSA) has developed 2 curricula for the specific purpose of training the next generation of clinicians to ensure the future infectious diseases (ID) workforce is optimally trained to lead antimicrobial stewardship programs and equipped to meet the challenges of multidrug resistance, patient safety, and healthcare quality improvement. A core curriculum was developed to provide a foundation in antimicrobial stewardship for all ID fellows, regardless of career path. An advanced curriculum was developed for ID fellows specifically pursuing a career in antimicrobial stewardship. Both curricula will be broadly available in the summer of 2021 through the IDSA website.


Asunto(s)
Programas de Optimización del Uso de los Antimicrobianos , Enfermedades Transmisibles , Curriculum , Atención a la Salud , Humanos , Sociedades
4.
Clin Infect Dis ; 67(8): 1285-1287, 2018 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-29668905

RESUMEN

A needs assessment survey of infectious diseases (ID) training program directors identified gaps in educational resources for training and evaluating ID fellows in antimicrobial stewardship. An Infectious Diseases Society of America-sponsored core curriculum was developed to address that need.


Asunto(s)
Programas de Optimización del Uso de los Antimicrobianos , Enfermedades Transmisibles , Curriculum , Educación de Postgrado en Medicina , Becas , Humanos , Evaluación de Necesidades , Preceptoría , Encuestas y Cuestionarios
5.
Int J Dev Neurosci ; 26(5): 423-34, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18423945

RESUMEN

Pharmacological studies indicate that vasoactive intestinal peptide (VIP) may be necessary for normal embryonic development in the mouse. For example, VIP antagonist treatment before embryonic day 11 resulted in developmental delays, growth restriction, modified adult brain chemistry and reduced social behavior. Here, developmental milestones, growth, and social behaviors of neonates of VIP-deficient mothers (VIP +/-) mated to VIP +/- males were compared with the offspring of wild type mothers (VIP +/+) mated to VIP +/+ and +/- males, to assess the contributions of both maternal and offspring VIP genotype. Regardless of their own genotype, all offsprings of VIP-deficient mothers exhibited developmental delays. No delays were seen in the offspring of wild type mothers, regardless of their own genotype. Body weights were significantly reduced in offspring of VIP-deficient mothers, with VIP null (-/-) the most affected. Regardless of genotype, all offspring of VIP-deficient mothers expressed reduced maternal affiliation compared with wild type offspring of wild type mothers; +/- offspring of wild type mothers did not differ in maternal affiliation from their wild type littermates. Play behavior was significantly reduced in all offsprings of VIP-deficient mothers. Maternal behavior did not differ between wild type and VIP-deficient mothers, and cross-fostering of litters did not change offspring development, indicating that offspring deficits were induced prenatally. This study illustrated that the VIP status of a pregnant mouse had a greater influence on the growth, development and behavior of her offspring than the VIP genotype of the offspring themselves. Deficiencies were apparent in +/+, +/- and -/- offspring born to VIP-deficient mothers; no deficiencies were apparent in +/- offspring born to normal mothers. These results underscore the significant contribution of the uterine environment to normal development and indicate a potential usefulness of the VIP knockout mouse in furthering the understanding of neurodevelopmental disorders with social behavior deficits such as autism.


Asunto(s)
Conducta Animal/fisiología , Conducta Social , Péptido Intestinal Vasoactivo/fisiología , Análisis de Varianza , Animales , Peso Corporal/genética , Peso Corporal/fisiología , Femenino , Genotipo , Masculino , Ratones , Ratones Noqueados , Péptido Intestinal Vasoactivo/deficiencia , Péptido Intestinal Vasoactivo/genética
6.
Infect Control Hosp Epidemiol ; 39(9): 1037-1041, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30064539

RESUMEN

OBJECTIVE: To characterize the microbiology of hepatobiliary surgical site infections (SSIs) and to explore the relationship between specific antimicrobial prophylaxis regimens and the development of SSIs. DESIGN: Retrospective matched case-control study comparing patient, procedure, and antimicrobial prophylaxis characteristics among patients undergoing a hepatobiliary surgical procedure with and without an SSI. SETTING: A tertiary referral acute-care facility. METHODS: Patients undergoing procedures defined as "BILI" (bile duct, liver, or pancreas surgery) using National Healthcare Safety Network (NHSN) definitions, excluding those undergoing concomitant liver transplantation, from January 2013 through June 2016 were included in the study population. The SSIs were identified through routine infection control surveillance using NHSN definitions. All patients who developed an SSI were considered cases. Controls were selected randomly matched 2:1 with cases based on fiscal quarter of the procedure. Logistic regression modeling was performed to explore variables associated with SSI, including antimicrobial prophylaxis received. RESULTS: Among 975 procedures, 80 (8.2%) resulted in an SSI. Most cases involved an organism nonsusceptible to standard prophylaxis regimens, including cefazolin (68.8%), cefazolin plus metronidazole (61.3%), and ampicillin-sulbactam (52.5%). In a multivariate model, antimicrobial coverage against Enterococcus spp (aOR, 0.58; 95% confidence interval [CI], 0.17-2.04; P=.40) and against Pseudomonas spp (aOR, 2.40; 95% CI, 0.56-10.29; P=.24) were not protective against the development of an SSI. The presence of a documented ß-lactam allergy was significantly associated with the development of an SSI (aOR, 3.54; 95% CI, 1.36-9.19; P=.009). CONCLUSIONS: Although SSIs at the study institution were associated with pathogens nonsusceptible to the most commonly used prophylaxis regimens, broader-spectrum coverage was not associated with a reduction in SSIs.


Asunto(s)
Antiinfecciosos/uso terapéutico , Profilaxis Antibiótica/estadística & datos numéricos , Procedimientos Quirúrgicos del Sistema Digestivo/efectos adversos , Infección de la Herida Quirúrgica/epidemiología , Anciano , Ampicilina/uso terapéutico , Boston/epidemiología , Estudios de Casos y Controles , Cefazolina/uso terapéutico , Combinación de Medicamentos , Femenino , Humanos , Modelos Logísticos , Masculino , Metronidazol/uso terapéutico , Persona de Mediana Edad , Análisis Multivariante , Atención Perioperativa , Estudios Retrospectivos , Factores de Riesgo , Sulbactam/uso terapéutico , Infección de la Herida Quirúrgica/prevención & control , beta-Lactamas/uso terapéutico
7.
J Mol Neurosci ; 33(3): 278-83, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17952637

RESUMEN

Vasoactive intestinal peptide (VIP) is an important mediator of development during the neural tube closure period of embryogenesis and may regulate, in part, the expression of activity-dependent neuroprotective protein (ADNP), which is essential for neural tube closure and embryogenesis. To evaluate the impact of VIP expression in vivo on ADNP and the related protein ADNP2 the current study examined gene expression in adult wild-type (VIP +/+) and VIP null (VIP -/-) offspring of VIP deficient mothers (VIP+/-) comparing them to wild-type offspring of wild-type mothers. Quantitative real time polymerase chain reaction (PCR), using an ABI Prisma cycler revealed regionally specific reductions of ADNP mRNA in the brains of VIP null mice compared with the brains of wild-type offspring of a wild-type mother. ADNP was significantly reduced in the cortex and hypothalamus of VIP null mice, but not in the hippocampus or thalamus. ADNP2 exhibited a similar pattern but reached a statistically significant reduction only in the hypothalamus. The mRNA for ADNP and ADNP2 also tended to be reduced in the cortex and hippocampus of the wild-type littermates of the VIP null mice, indicating that the VIP genotype of the mother may have had an impact on the ADNP expression of her offspring, regardless of their own VIP genotype. These results showed that VIP regulated brain ADNP expression in a regionally specific manner and indicated that both maternal and offspring VIP genotype may influence ADNP expression in the brain.


Asunto(s)
Proteínas de Homeodominio/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Fármacos Neuroprotectores/metabolismo , Neurulación/fisiología , Isoformas de Proteínas/metabolismo , Péptido Intestinal Vasoactivo/metabolismo , Animales , Encéfalo/anatomía & histología , Encéfalo/metabolismo , Femenino , Proteínas de Homeodominio/genética , Ratones , Ratones Noqueados , Proteínas del Tejido Nervioso/genética , Embarazo , Isoformas de Proteínas/genética , Péptido Intestinal Vasoactivo/genética
8.
Behav Neurosci ; 120(1): 173-9, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16492127

RESUMEN

The authors tested how prior odor enrichment affects the spontaneous discrimination of both preexposed and novel odors. Experimental rats were exposed to single odors or to pairs of similar or dissimilar odors for 1-hr periods twice daily over 20 days. Spontaneous discriminations between pairs of similar odors were tested before and after the odor exposure period using an olfactory habituation task. The authors found that (a) experimental rats did not spontaneously discriminate similar odor pairs before the exposure period, whereas they spontaneously discriminated them after the enrichment period, and (b) the improvement of performance was not selective for the odors used during enrichment. These results show that odor experience changes perception in the manner predicted based on other groups' electrophysiological experiments.


Asunto(s)
Discriminación en Psicología/fisiología , Odorantes , Olfato/fisiología , Animales , Habituación Psicofisiológica , Masculino , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley
9.
Physiol Behav ; 89(3): 379-84, 2006 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-16904713

RESUMEN

Odor mixtures can exhibit synthetic (the mixture is qualitatively different from its components) or elemental properties (the components are recognizable). We tested how prior olfactory enrichment affects the recognition of individual components in binary mixtures. Experimental rats were exposed to pairs of similar odors for one-hour periods twice daily over 20 days. Spontaneous discrimination between the binary mixture and the individual components of similar pairs of odors was tested before and after the odor enrichment. We found that, after the enrichment period, rats could discriminate components in binary mixtures that had not been discriminated prior to the enrichment period, and that this increase in discrimination capability was not always specific to the odorants used during the enrichment period.


Asunto(s)
Discriminación en Psicología/fisiología , Odorantes , Reconocimiento en Psicología/fisiología , Olfato/fisiología , Análisis de Varianza , Animales , Conducta Animal , Habituación Psicofisiológica/fisiología , Masculino , Ratas , Ratas Sprague-Dawley , Tiempo de Reacción/fisiología , Umbral Sensorial/fisiología
10.
J Acquir Immune Defic Syndr ; 71(1): 94-101, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26371786

RESUMEN

INTRODUCTION: Pre-exposure prophylaxis (PrEP), taken as a single daily coformulated pill containing tenofovir -emtricitabine, is a promising intervention to reduce the likelihood of HIV acquisition in at-risk individuals, including men who have sex with men. Little is known about the acceptability of less than daily, intermittent PrEP regimens. METHODS: We conducted an online survey of North American men who have sex with men to characterize their sexual frequency and planning behaviors and correlate these with PrEP dosing preferences. RESULTS: Of the 3217 respondents who completed the survey, 46% reported engaging in unplanned condomless anal intercourse (CAI) at least once in previous 3 months and 8% reported engaging in CAI more than once per week. In multivariable analysis, reporting unplanned CAI was associated with lower educational level, identifying as homosexual/gay as compared with bisexual, being in a monogamous relationship, having a higher self-perceived risk of HIV acquisition, reporting higher income, engaging in CAI more than five times in the last 3 months, and not having visited a health care provider in the previous year. Frequent CAI (>1 time per week) was associated with being younger, identifying as homosexual/gay as compared with bisexual, being in a monogamous relationship, and having a higher self-perceived risk of HIV. Having only planned sex over the last 3 months was associated with a preference for event-based PrEP, whereas having frequent or unplanned CAI was associated with a preference for daily or time-driven PrEP regimens, respectively. CONCLUSION: Our findings suggest that preferences for different PrEP regimens are associated with the sexual frequency and planning behaviors of potential users.


Asunto(s)
Fármacos Anti-VIH/administración & dosificación , Infecciones por VIH/prevención & control , Homosexualidad Masculina , Aceptación de la Atención de Salud/estadística & datos numéricos , Profilaxis Pre-Exposición/métodos , Sexo Inseguro/estadística & datos numéricos , Adulto , Escolaridad , Conocimientos, Actitudes y Práctica en Salud , Homosexualidad Masculina/psicología , Homosexualidad Masculina/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Factores de Riesgo , Parejas Sexuales , Estados Unidos , Adulto Joven
11.
Sci Transl Med ; 8(370): 370ra181, 2016 12 21.
Artículo en Inglés | MEDLINE | ID: mdl-28003546

RESUMEN

Spinobulbar muscular atrophy (SBMA) is an X-linked neuromuscular disease caused by polyglutamine (polyQ) expansion in the androgen receptor (AR) gene. SBMA belongs to the family of polyQ diseases, which are fatal neurodegenerative disorders mainly caused by protein-mediated toxic gain-of-function mechanisms and characterized by deposition of misfolded proteins in the form of aggregates. The neurotoxicity of the polyQ proteins can be modified by phosphorylation at specific sites, thereby providing the rationale for the development of disease-specific treatments. We sought to identify signaling pathways that modulate polyQ-AR phosphorylation for therapy development. We report that cyclin-dependent kinase 2 (CDK2) phosphorylates polyQ-AR specifically at Ser96 Phosphorylation of polyQ-AR by CDK2 increased protein stabilization and toxicity and is negatively regulated by the adenylyl cyclase (AC)/protein kinase A (PKA) signaling pathway. To translate these findings into therapy, we developed an analog of pituitary adenylyl cyclase activating polypeptide (PACAP), a potent activator of the AC/PKA pathway. Chronic intranasal administration of the PACAP analog to knock-in SBMA mice reduced Ser96 phosphorylation, promoted polyQ-AR degradation, and ameliorated disease outcome. These results provide proof of principle that noninvasive therapy based on the use of PACAP analogs is a therapeutic option for SBMA.


Asunto(s)
Trastornos Musculares Atróficos/metabolismo , Péptidos/química , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Receptores Androgénicos/metabolismo , Animales , Proliferación Celular , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Quinasa 2 Dependiente de la Ciclina/metabolismo , Glutamina/metabolismo , Células HEK293 , Humanos , Ligandos , Potencial de la Membrana Mitocondrial , Ratones , Ratones Transgénicos , Células PC12 , Fosforilación , Desnaturalización Proteica , Pliegue de Proteína , Ratas , Ratas Sprague-Dawley , Transducción de Señal
12.
Neuron ; 63(3): 316-28, 2009 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-19679072

RESUMEN

Expansion of a polyglutamine tract in the androgen receptor (AR) causes spinal and bulbar muscular atrophy (SBMA). We previously showed that Akt-mediated phosphorylation of AR reduces ligand binding and attenuates the mutant AR toxicity. Here, we show that in culture insulin-like growth factor 1 (IGF-1) reduces AR aggregation and increases AR clearance via the ubiquitin-proteasome system through phosphorylation of AR by Akt. In vivo, SBMA transgenic mice overexpressing a muscle-specific isoform of IGF-1 selectively in skeletal muscle show evidence of increased Akt activation and AR phosphorylation and decreased AR aggregation. Augmentation of IGF-1/Akt signaling rescues behavioral and histopathological abnormalities, extends the life span, and reduces both muscle and spinal cord pathology of SBMA mice. This study establishes IGF-1/Akt-mediated inactivation of mutant AR as a strategy to counteract disease in vivo and demonstrates that skeletal muscle is a viable target tissue for therapeutic intervention in SBMA.


Asunto(s)
Regulación de la Expresión Génica/genética , Factor I del Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/metabolismo , Músculo Esquelético/metabolismo , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/patología , Atrofia Muscular/fisiopatología , Animales , Conducta Animal/efectos de los fármacos , Conducta Animal/fisiología , Línea Celular Transformada , Chlorocebus aethiops , Fosfatidilinositol 3-Quinasa Clase I , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Factor I del Crecimiento Similar a la Insulina/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Músculo Esquelético/efectos de los fármacos , Atrofia Muscular Espinal/mortalidad , Atrofia Muscular Espinal/terapia , Mutación/genética , Proteína Oncogénica v-akt/metabolismo , Péptidos/genética , Péptidos/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación/efectos de los fármacos , Fosforilación/genética , Receptores Androgénicos/genética , Receptores Androgénicos/metabolismo , Serina/metabolismo , Factores de Tiempo , Transfección/métodos , Expansión de Repetición de Trinucleótido/efectos de los fármacos , Expansión de Repetición de Trinucleótido/fisiología , Ubiquitina/metabolismo
13.
Exp Neurol ; 211(1): 67-84, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18316078

RESUMEN

Blockage of vasoactive intestinal peptide (VIP) receptors during early embryogenesis in the mouse has been shown to result in developmental delays in neonates, and social behavior deficits selectively in adult male offspring. Offspring of VIP deficient mothers (VIP +/-) also exhibited developmental delays, and reductions in maternal affiliation and play behavior. In the current study, comparisons among the offspring of VIP deficient mothers (VIP +/-) mated to VIP +/- males with the offspring of wild type (WT) mothers mated to VIP +/- males allowed assessment of the contributions of both maternal and offspring VIP genotype to general health measures, social behavior, fear conditioning, and spatial learning and memory in the water maze. These comparisons revealed few differences in general health among offspring of WT and VIP deficient mothers, and all offspring exhibited normal responses in fear conditioning and in the acquisition phase of spatial discrimination in the water maze. WT mothers produced offspring that were normal in all tests; the reduced VIP in their VIP +/- offspring apparently did not contribute to any defects in the measures under study. However, regardless of their own VIP genotype, all male offspring of VIP deficient mothers exhibited severe deficits in social approach behavior and reversal learning. The deficits in these behaviors in the female offspring of VIP deficient mothers were less severe than in their male littermates, and the extent of their impairment was related to their own VIP genotype. This study has shown that intrauterine conditions had a greater influence on behavioral outcome than did genetic inheritance. In addition, the greater prevalence of deficits in social behavior and the resistance to change seen in reversal learning in the male offspring of VIP deficient mothers indicate a potential usefulness of the VIP knockout mouse in furthering the understanding of neurodevelopmental disorders such as autism.


Asunto(s)
Discapacidades para el Aprendizaje/genética , Aprendizaje Inverso/fisiología , Caracteres Sexuales , Conducta Social , Péptido Intestinal Vasoactivo/deficiencia , Análisis de Varianza , Animales , Conducta Animal , Condicionamiento Psicológico/fisiología , Conducta Exploratoria/fisiología , Miedo/fisiología , Femenino , Habituación Psicofisiológica/genética , Masculino , Aprendizaje por Laberinto , Ratones , Ratones Noqueados , Vías Olfatorias/fisiología , Reflejo/genética , Conducta Espacial/fisiología , Factores de Tiempo
14.
Proc Natl Acad Sci U S A ; 103(36): 13543-8, 2006 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-16938883

RESUMEN

A number of electrophysiological experiments have shown that odor exposure alone, unaccompanied by behavioral training, changes the response patterns of neurons in the olfactory bulb. As a consequence of these changes, across mitral cells in the olfactory bulb, individual odors should be better discriminated because of previous exposure. We have previously shown that a daily 2-h exposure to odorants during 2 weeks enhances rats' ability to discriminate between chemically similar odorants. Here, we first show that the perception of test odorants is only modulated by enrichment with odorants that activate at least partially overlapping regions of the olfactory bulb. Second, we show that a broad activation of olfactory bulb neurons by daily local infusion of NMDA into both olfactory bulbs enhances the discrimination between chemically related odorants in a manner similar to the effect of daily exposure to odorants. Computational modeling of the olfactory bulb suggests that activity-dependent plasticity in the olfactory bulb can support the observed modulation in olfactory discrimination capability by enhancing contrast and synchronization in the olfactory bulb. Last, we show that blockade of NMDA receptors in the olfactory bulb impairs the effects of daily enrichment, suggesting that NMDA-dependent plasticity is involved in the changes in olfactory processing observed here.


Asunto(s)
Odorantes , Bulbo Olfatorio/fisiología , Olfato , Animales , Simulación por Computador , Condicionamiento Psicológico/fisiología , Discriminación en Psicología/fisiología , Masculino , Modelos Biológicos , N-Metilaspartato/metabolismo , N-Metilaspartato/farmacología , Neuronas Aferentes/fisiología , Bulbo Olfatorio/citología , Bulbo Olfatorio/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/metabolismo , Factores de Tiempo
15.
Eur J Neurosci ; 24(11): 3234-44, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17156384

RESUMEN

Cholinergic neuromodulation in the olfactory bulb has been hypothesized to regulate mitral cell molecular receptive ranges and the behavioral discrimination of similar odorants. We tested the effects of cholinergic modulation in the olfactory bulb of cannulated rats by bilaterally infusing cholinergic agents into the olfactory bulbs and measuring the rats' performances on separate spontaneous and motivated odor-discrimination tasks. Specifically, 6 microL/bulb infusions of vehicle (0.9% saline), the muscarinic antagonist scopolamine (7.6 mM and 38 mM), the nicotinic antagonist mecamylamine hydrochloride (3.8 mM and 19 mM), a combination of both antagonists, or the acetylcholinesterase inhibitor neostigmine (8.7 mM) were made 20 min prior to testing on an olfactory cross-habituation task or a rewarded, forced-choice odor-discrimination task. Spontaneous discrimination between chemically related odorants was abolished when nicotinic receptors were blocked in the olfactory bulb, and enhanced when the efficacy of cholinergic inputs was increased with neostigmine. Blocking muscarinic receptors reduced but did not abolish odor discrimination. Interestingly, no behavioral effects of modulating either nicotinic or muscarinic receptors were observed when rats were trained on a reward-motivated odor-discrimination task. Computational modeling of glomerular circuitry demonstrates that known nicotinic cholinergic effects on bulbar neurons suffice to explain these results.


Asunto(s)
Acetilcolina/metabolismo , Vías Aferentes/metabolismo , Fibras Colinérgicas/metabolismo , Bulbo Olfatorio/metabolismo , Olfato/fisiología , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Vías Aferentes/citología , Vías Aferentes/efectos de los fármacos , Animales , Fibras Colinérgicas/efectos de los fármacos , Fibras Colinérgicas/ultraestructura , Inhibidores de la Colinesterasa/farmacología , Masculino , Antagonistas Muscarínicos/farmacología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Antagonistas Nicotínicos/farmacología , Odorantes , Bulbo Olfatorio/citología , Bulbo Olfatorio/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores Muscarínicos/efectos de los fármacos , Receptores Muscarínicos/metabolismo , Receptores Nicotínicos/efectos de los fármacos , Receptores Nicotínicos/metabolismo , Núcleos Septales/citología , Núcleos Septales/efectos de los fármacos , Núcleos Septales/metabolismo , Olfato/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiología
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