RESUMO
Central nervous system neurons communicate via fast synaptic transmission mediated by ligand-gated ion channel (LGIC) receptors and slower neuromodulation mediated by G protein-coupled receptors (GPCRs). These receptors influence many neuronal functions, including presynaptic neurotransmitter release. Presynaptic LGIC and GPCR activation by locally released neurotransmitters influences neuronal communication in ways that modify effects of somatic action potentials. Although much is known about presynaptic receptors and their mechanisms of action, less is known about when and where these receptor actions alter release, especially in vivo. This Review focuses on emerging evidence for important local presynaptic receptor actions and ideas for future studies in this area.
Assuntos
Comunicação Celular , Receptores Pré-Sinápticos , Potenciais de Ação , Humanos , Neurônios , Transmissão SinápticaRESUMO
PURPOSE: This study aimed to assess the acceptability, relevance, and effectiveness of a patient acuity tool (PAT) among part-time and full-time RNs. METHODS: A pre- and post-test intervention was used to evaluate a PAT among part-time and full-time RNs on a 28-bed telemetry unit at a Magnet®-designated hospital. An eight-item PAT questionnaire measured nurse acceptability. Relevance was evaluated using the RN Opinion of Relevance of Concepts of the PAT Questionnaire, and effectiveness was evaluated using the RN Opinion of Effectiveness of the PAT Questionnaire. RESULTS: A total of 22/33 (66.6%) RNs participated and completed the PAT questionnaire that measured nurse acceptability of the PAT assessment process. Statistically significant differences were demonstrated between two out of eight variables pre-post intervention; "the way we currently evaluate patient acuity assists the charge nurse in making nurse-patient assignments" (t 3.070, df 22, P = .006), "the way we currently evaluate patient acuity is an accurate assessment of acuity" (t 2.390, df 22, P = .026). CONCLUSION: Acuity tools should be specific for a nursing unit and adapt to staffing and patient needs, which can include a change in a patient's condition, unexpected discharges and/or admissions, and psychosocial components.
Assuntos
Recursos Humanos de Enfermagem Hospitalar , Humanos , Recursos Humanos de Enfermagem Hospitalar/psicologia , Gravidade do Paciente , Estudantes , Hospitais , Inquéritos e Questionários , Admissão e Escalonamento de PessoalRESUMO
Introduction: Coronavirus disease 2019 (COVID-19) has forced health care systems to rethink the optimal delivery of health care services and has dramatically increased demand for general medicine providers (internal medicine, family medicine, emergency medicine), while simultaneously reducing demand for many subspecialty services. At Kaiser Permanente, we implemented a program wherein health care providers drawn from multiple disciplines perform daily telemedicine check-ins on COVID-19 patients, allowing us to both maintain social distancing and make use of providers in specialties who otherwise may have had lower in-clinic volumes. Methods: Kaiser Permanente patients testing positive for COVID-19 between March and October 2020 were referred to our program. Physicians and nurses (RNs) were invited to participate in our program and were trained using Microsoft Teams™ meetings. Patients receive daily phone calls by a physician or RN. Select patients receive portable pulse oximeter devices based on standardized criteria incorporating age and comorbidities. When patients are determined to be clinically stable, they are discharged back to their primary care physician for ongoing management. Results: Descriptive results for the virtual home care program (VHCP) are reported through October 2020, though these results do not represent a planned statistical analysis. Forty-two percent of the patients were male, 43% were black, and 30% were Hispanic. The most common comorbidities of patients in our program were obesity (body mass index >30 kg/m2; 35%), followed by hypertension (32%) and diabetes mellitus (19%). Then, 8.2% of patients ultimately required hospital admission. Mortality rate for patients in our program was 1.33%. Discussion: Our program was able to provide virtual care for thousands of COVID-19 positive Kaiser members in the Washington, DC, and Baltimore Metro regions. We did so by utilizing physicians and RNs from specialties experiencing a decrease in clinic volume attributable to the COVID-19 pandemic. The experiences of our program may be valuable to clinicians wishing to establish similar programs of their own.
Assuntos
COVID-19 , Telemedicina , Atenção à Saúde , Humanos , Masculino , Pandemias , SARS-CoV-2RESUMO
When a patient is admitted to a hospital, admission assessments are completed in the electronic medical record. There is minimal information about who the person is, what they liked to be called, favorite activity, and or past occupation to view. A communication board is visible to all caring for the patient. This pre-post design evaluated whether using "All About Me Board" (AAMB) could change workplace climate perception among 25 registered nurses (RN)s in a 28 bed medical surgical unit. RNs were asked to participate in a Person Centered Climate Questionnaire and were provided education about purpose and use of the AAMB, which were placed in each patient's room. Having the AAMB placed and visible in patient rooms provided healthcare providers personal information to assist in planning care with patients and family. Survey results were favorable in supporting a workplace environment where patients were empowered to participate in planning their care.
Assuntos
Cuidados de Enfermagem , Hospitais , Humanos , Assistência Centrada no Paciente , Inquéritos e Questionários , Local de TrabalhoRESUMO
The health care settings of today are rapidly evolving in form and function, challenging nurse executives to adopt, adapt, and develop new ways to lead and find professional fulfillment in their roles. The organizational design of many health care settings has changed from a functional to a matrix structure to facilitate more effective and efficient operations. While the structures and reporting relationship of contemporary nurse executives may have changed significantly, the primary responsibility of championing the advancement of the profession of nursing remains essential. The mastery of change management methods is critical for the nurse executive to successfully lead in today's dynamic health care settings. A well-developed and actualized nursing professional practice model is a foundational tool for the nurse executive to employ to advance the profession of nursing in any health care setting or structure. This article describes how a nurse executive used change management methods and principles to lead the development of a new network-wide unifying nursing professional practice model in a highly matrixed health care setting.
Assuntos
Enfermeiros Administradores , Atenção à Saúde , Humanos , Liderança , Prática ProfissionalRESUMO
Dynamic regulation of synaptic transmission at cortical inputs to the dorsal striatum is considered critical for flexible and efficient action learning and control. Presynaptic mechanisms governing the properties and plasticity of glutamate release from these inputs are not fully understood, and the corticostriatal synaptic processes that support normal action learning and control remain unclear. Here we show in male and female mice that conditional deletion of presynaptic proteins RIM1αß (RIM1) from excitatory cortical neurons impairs corticostriatal synaptic transmission in the dorsolateral striatum. Key forms of presynaptic G-protein-coupled receptor-mediated short- and long-term striatal plasticity are spared following RIM1 deletion. Conditional RIM1 KO mice show heightened novelty-induced locomotion and impaired motor learning on the accelerating rotarod. They further show heightened self-paced instrumental responding for food and impaired learning of a habitual instrumental response strategy. Together, these findings reveal a selective role for presynaptic RIM1 in neurotransmitter release at prominent basal ganglia synapses, and provide evidence that RIM1-dependent processes help to promote the refinement of skilled actions, constrain goal-directed behaviors, and support the learning and use of habits.SIGNIFICANCE STATEMENT Our daily functioning hinges on the ability to flexibly and efficiently learn and control our actions. How the brain encodes these capacities is unclear. Here we identified a selective role for presynaptic proteins RIM1αß in controlling glutamate release from cortical inputs to the dorsolateral striatum, a brain structure critical for action learning and control. Behavioral analysis of mice with restricted genetic deletion of RIM1αß further revealed roles for RIM1αß-dependent processes in the learning and refinement of motor skills and the balanced expression of goal-directed and habitual actions.
Assuntos
Córtex Cerebral/fisiologia , Corpo Estriado/fisiologia , Proteínas de Ligação ao GTP/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Animais , Gânglios da Base/fisiologia , Condicionamento Operante/fisiologia , Comportamento Exploratório/fisiologia , Feminino , Proteínas de Ligação ao GTP/deficiência , Proteínas de Ligação ao GTP/genética , Ácido Glutâmico/fisiologia , Hábitos , Aprendizagem/fisiologia , Deficiências da Aprendizagem/genética , Deficiências da Aprendizagem/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Destreza Motora/fisiologia , Proteínas do Tecido Nervoso/deficiência , Proteínas do Tecido Nervoso/genética , Plasticidade Neuronal , Técnicas de Patch-Clamp , Células Piramidais/fisiologia , Receptores Acoplados a Proteínas G/fisiologia , Teste de Desempenho do Rota-Rod , Transmissão Sináptica/fisiologiaRESUMO
BACKGROUND: Optimizing early education in gynecological procedures utilizing an Enhanced Recovery after Surgery (ERAS) program and a bundle concept may optimize patient outcomes after surgery. PURPOSE: Evaluate whether an ERAS bundle compared to standard education can affect length of stay, 30 day readmission, and patient satisfaction among patients undergoing gynecologic surgery. DESIGN: Prospective, comparative, randomized design SETTING: 28 bed Medical Surgical Unit SAMPLE/INTERVENTION: 50 patients undergoing hysterectomy, 25 who received post-operative evidence based bundle/standard education, and 25 who received standard education packet. Bundle components included 1) early mobilization, 2) early transition to oral pain medication, 3) early feeding, and 4) chewing gum. A follow-up phone call was made in two to three days following discharge for both groups utilizing teach-back. RESULTS: 84% (nâ¯=â¯21) patients in the bundle group were discharged in one day. There were no 30 day readmissions for both groups. Twenty two (88%) participants met the bundle components 100% of the time. For the indicator "walking helped with recovery" 100% (nâ¯=â¯25) responded "very good to excellent" for bundle group and 96% (nâ¯=â¯24) responded "very good to excellent" for standard group. Twenty three (92%) of the bundle group felt that that overall nursing care received was very good to excellent and 24 (96%) of the general group felt that overall nursing care received was very good to excellent. CONCLUSION: Optimizing peri-operative education using a bundle approach to provide evidence based interventions can minimize risk and enhance early recovery for females undergoing gynecological surgery.
Assuntos
Procedimentos Cirúrgicos em Ginecologia/efeitos adversos , Procedimentos Cirúrgicos em Ginecologia/educação , Tempo de Internação/estatística & dados numéricos , Alta do Paciente/estatística & dados numéricos , Educação de Pacientes como Assunto/métodos , Readmissão do Paciente/estatística & dados numéricos , Complicações Pós-Operatórias/prevenção & controle , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Procedimentos Cirúrgicos em Ginecologia/estatística & dados numéricos , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Recuperação de Função FisiológicaRESUMO
Metabotropic glutamate (mGlu) receptors play important roles in regulating CNS function and are known to function as obligatory dimers. Although recent studies have suggested heterodimeric assembly of mGlu receptors in vitro, the demonstration that distinct mGlu receptor proteins can form heterodimers or hetero-complexes with other mGlu subunits in native tissues, such as neurons, has not been shown. Using biochemical and pharmacological approaches, we demonstrate here that mGlu2 and mGlu4 form a hetero-complex in native rat and mouse tissues which exhibits a distinct pharmacological profile. These data greatly extend our current understanding of mGlu receptor interaction and function and provide compelling evidence that mGlu receptors can function as heteromers in intact brain circuits.
Assuntos
Encéfalo/fisiologia , Receptores de Glutamato Metabotrópico/fisiologia , Regulação Alostérica/efeitos dos fármacos , Regulação Alostérica/fisiologia , Animais , Encéfalo/efeitos dos fármacos , Células Cultivadas , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/fisiologia , Agonistas de Aminoácidos Excitatórios/química , Agonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas de Aminoácidos Excitatórios/química , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Multimerização Proteica , Ratos , Ratos Sprague-Dawley , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Receptores de Glutamato Metabotrópico/químicaAssuntos
Acidentes por Quedas/prevenção & controle , Acidentes por Quedas/estatística & dados numéricos , Cuidados Críticos/normas , Hospitais/normas , Guias de Prática Clínica como Assunto , Gestão da Segurança/estatística & dados numéricos , Gestão da Segurança/normas , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição de RiscoAssuntos
Embalagem de Medicamentos/métodos , Tratamento Farmacológico/enfermagem , Insulina/administração & dosagem , Erros de Medicação/prevenção & controle , Gestão da Segurança/organização & administração , Adolescente , Adulto , Registros Eletrônicos de Saúde , Humanos , Pessoa de Meia-Idade , Pesquisa em Avaliação de Enfermagem , Recursos Humanos de Enfermagem Hospitalar/psicologia , Recursos Humanos de Enfermagem Hospitalar/estatística & dados numéricos , Estados Unidos , Adulto JovemRESUMO
Elephant movement patterns in relation to surface water demonstrate that they are a water-dependent species. Thus, there has been interest in using surface water management to mitigate problems associated with localized elephant overabundance. However, the physiological mechanisms underlying the elephant's water dependence remain unclear. Although thermoregulation is likely an important driver, the relationship between thermoregulation, water use and climate has not been quantified. We measured skin surface temperature of and cutaneous water loss from 13 elephants (seven African, 3768±642 kg; six Asian, 3834±498 kg) and determined the contribution of evaporative cooling to their thermal and water budgets across a range of air temperatures (8-33°C). We also measured respiratory evaporative water loss and resting metabolic heat production on a subset of elephants (N=7). The rate of cutaneous evaporative water loss ranged between 0.31 and 8.9 g min(-1) m(-2) for Asian elephants and 0.26 and 6.5 g min(-1) m(-2) for African elephants. Simulated thermal and water budgets using climate data from Port Elizabeth, South Africa, and Okaukuejo, Namibia, suggested that the 24-h evaporative cooling water debt incurred in warm climates can be more than 4.5 times that incurred in mesic climates. This study confirms elephants are obligate evaporative coolers but suggests that classification of elephants as water dependent is insufficient given the importance of climate in determining the magnitude of this dependence. These data highlight the potential for a physiological modeling approach to predicting the utility of surface water management for specific populations.
Assuntos
Regulação da Temperatura Corporal/fisiologia , Clima , Elefantes/fisiologia , Água/metabolismo , África , Animais , Ásia , Epiderme/fisiologia , Feminino , Masculino , Permeabilidade , Dinâmica Populacional , Respiração , Temperatura , Perda Insensível de ÁguaRESUMO
Dopamine transmission in the striatum is a critical mediator of the rewarding and reinforcing effects of commonly misused psychoactive drugs. G protein-coupled receptors (GPCRs) that bind a variety of neuromodulators including dopamine, endocannabinoids, acetylcholine and endogenous opioid peptides regulate dopamine release by acting on several components of dopaminergic circuitry. Striatal dopamine release can be driven by both somatic action potential firing and local mechanisms that depend on acetylcholine released from striatal cholinergic interneurons. GPCRs that primarily regulate somatic firing of dopamine neurons via direct effects or modulation of synaptic inputs are likely to affect distinct aspects of behaviour and psychoactive drug actions compared with those GPCRs that primarily regulate local acetylcholine-dependent dopamine release in striatal regions. This review will highlight mechanisms by which GPCRs modulate dopaminergic transmission and the relevance of these findings to psychoactive drug effects on physiology and behaviour.
RESUMO
The successful employment of morphogenic regulator genes, Zm-Baby Boom (ZmBbm) and Zm-Wuschel2 (ZmWus2), for Agrobacterium-mediated transformation of maize (Zea mays L.) and sorghum (Sorghum bicolor L.) has been reported to improve transformation by inducing rapid somatic embryo formation. Here, we report two morphogenic gene-mediated wheat transformation methods, either with or without morphogenic and marker gene excision. These methods yield independent-transformation efficiency up to 58% and 75%, respectively. In both cases, the tissue culture duration for generating transgenic plants was significantly reduced from 80 to nearly 50 days. In addition, the transformation process was significantly simplified to make the procedure less labor-intensive, higher-throughput, and more cost-effective by eliminating the requirement for embryonic axis excision, bypassing the necessity for prolonged dual-selection steps for callus formation, and obviating the prerequisite of cytokinin for shoot regeneration. Furthermore, we have demonstrated the flexibility of the methods and generated high-quality transgenic events across multiple genotypes using herbicide (phosphinothricin, ethametsulfuron)- and antibiotic (G418)-based selections.
RESUMO
Three captive-born (5-day-old, 8-day-old, and 4-yr-old) Asian elephants (Elephas maximus) and one captive-born 22-yr-old African elephant (Loxodonta africana) from three private elephant facilities and one zoo in the United States presented with depression, anorexia, and tachycardia as well as gastrointestinal signs of disease including abdominal distention, decreased borborygmi, tenesmus, hematochezia, or diarrhea. All elephants showed some evidence of discomfort including agitation, vocalization, or postural changes. One animal had abnormal rectal findings. Nonmotile bowel loops were seen on transabdominal ultrasound in another case. Duration of signs ranged from 6 to 36 hr. All elephants received analgesics and were given oral or rectal fluids. Other treatments included warm-water enemas or walking. One elephant underwent exploratory celiotomy. Three animals died, and the elephant taken to surgery was euthanized prior to anesthetic recovery. At necropsy, all animals had severe, strangulating intestinal lesions.
Assuntos
Elefantes , Obstrução Intestinal/veterinária , Animais , Animais Recém-Nascidos , Evolução Fatal , Feminino , Obstrução Intestinal/patologia , MasculinoRESUMO
The prefrontal cortex (PFC) is intimately associated with behavioral characteristics of alcohol use disorders, including high motivation to drink and difficulty with moderation. Thus, continued mechanistic research investigating PFC cells and targets altered by ethanol experiences should inform translational efforts to craft new, efficacious treatments. Inhibitory interneurons expressing parvalbumin (PV-INs) comprise only a minor fraction of cells within the PFC, yet these cells are indispensable for coordinating PFC ensemble function, oscillatory activity, and subcortical output. Based on this, PV-INs represent an exciting target for the rational design of breakthrough treatments for alcohol use disorders. Here, we assessed experience-dependent physiological adaptations via ethanol place conditioning. By manipulating the timing of administration relative to conditioning sessions, equivalent ethanol exposure can form either rewarding or aversive memories in different individuals. Here, we found that female mice and male mice on a C57BL/6J background display conditioned place preference (CPP) or aversion (CPA) to an intoxicating dose of ethanol (2 g/kg, intraperitoneal [i.p.]) without overt differences between sexes. Ethanol reward learning was associated with decreased PV-IN excitability in deep layer prelimbic PFC, whereas PV-INs from CPA mice were not different from controls. Furthermore, PV-INs from mice in the CPP group, but not the CPA group, displayed potentiated excitatory synaptic strength that emerged during 1 week of abstinence. Taken together, these findings illustrate that synaptic and intrinsic adaptations associated with ethanol can depend on an individual's experience. These studies provide further context and support for PFC PV-INs as intriguing targets for modulating alcohol associations.
Assuntos
Alcoolismo , Parvalbuminas , Animais , Etanol/farmacologia , Feminino , Interneurônios/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Parvalbuminas/metabolismo , Córtex Pré-Frontal/metabolismo , RecompensaRESUMO
UNLABELLED: In the previous work, we reported a method that utilized imaging data collected from 60 to 120 min following [(18) F]fallypride administration to estimate the distribution volume ratio DVR' (DVR' â DVR; DVR = 1 + BP(ND) , where BP(ND) is a measure of receptor density, DA D2 in this case). In this work, we use this method to assess the effects of isoflurane anesthesia on [(18) F]fallypride DVR'. METHODS: Rats were injected with [(18) F]fallypride either unconsciously under â¼1.5% isoflurane via the tail vein (Group 1) or consciously via a catheter inserted either in the jugular vein (Group 2) or the tail vein (Group 3). After about 1 h of free access to food and water the rats were anesthetized with 1.5% isoflurane and imaged in a microPET for 60 min. The rats that were injected consciously (Groups 2 and 3) were placed in a rat restrainer during [(18) F]fallypride injection. They were habituated in that restrainer for 3 days prior to the experiment day to minimize restraint-related stress. For comparison, a control group of rats was imaged for 120 min simultaneously with the administration of [(18) F]fallypride i.v. while under 1.5% isoflurane. The DVR' estimates from the 60 min acquisitions were compared with the DVR' from the last 60 min of the 120 min acquisitions (after neglecting the first 60 min). In addition, the striatal time-activity curves were fit with a 2-tissue + plasma compartment model using an arbitrary simulated plasma input function to obtain k(3) /k(4) (≈ BP(ND) ) for the 60 and 120 min acquisitions. RESULTS: Isoflurane anesthesia caused a significant reduction, up to 22%, in the DVR' estimates, which were 15.7 ± 0.3 (mean ± SE) for the controls, 17.7 ± 0.3 for Group 1, 19.2 ± 0.4 for Group 2, and 18.8 ± 0.7 for Group 3. The compartmental model fit produced similar results, â¼30% reduction in k(3) /k(4) for the 120-min acquisitions compared with the 60-min acquisitions (initial conscious uptake of the radiotracer). CONCLUSION: The results of this study demonstrate that isoflurane anesthesia significantly decreases striatal [(18) F]fallypride BP(ND) in rats. Of similar importance, this work demonstrates the effectiveness of delayed scans following radiotracer injection and the implication that different types of studies can be conducted simultaneously with this method, including studies of behavioral and environmental impact on brain receptors.
Assuntos
Anestesia por Inalação , Benzamidas , Radioisótopos de Flúor , Isoflurano/farmacologia , Tomografia por Emissão de Pósitrons/métodos , Pirrolidinas , Receptores de Dopamina D2/metabolismo , Anestesia por Inalação/métodos , Animais , Masculino , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/fisiologia , Compostos Radiofarmacêuticos , Ratos , Ratos Sprague-Dawley , Receptores de Dopamina D2/agonistasRESUMO
Phenotypic studies of mice lacking metabotropic glutamate receptor subtype 7 (mGluR7) suggest that antagonists of this receptor may be promising for the treatment of central nervous system disorders such as anxiety and depression. Suzuki et al. (J Pharmacol Exp Ther 323:147-156, 2007) recently reported the in vitro characterization of a novel mGluR7 antagonist called 6-(4-methoxyphenyl)-5-methyl-3-(4-pyridinyl)-isoxazolo[ 4,5-c]pyridin-4(5H)-one (MMPIP), which noncompetitively inhibited the activity of orthosteric and allosteric agonists at mGluR7. We describe that MMPIP acts as a noncompetitive antagonist in calcium mobilization assays in cells coexpressing mGluR7 and the promiscuous G protein G alpha(15). Assessment of the activity of a small library of MMPIP-derived compounds using this assay reveals that, despite similar potencies, compounds exhibit differences in negative cooperativity for agonist-mediated calcium mobilization. Examination of the inhibitory activity of MMPIP and analogs using endogenous G(i/o)-coupled assay readouts indicates that the pharmacology of these ligands seems to be context-dependent, and MMPIP exhibits differences in negative cooperativity in certain cellular backgrounds. Electrophysiological studies reveal that, in contrast to the orthosteric antagonist (2S)-2-amino-2-[(1S,2S)-2-carboxyclycloprop-1-yl]-3-(xanth-9-yl) propanoic acid (LY341495), MMPIP is unable to block agonist-mediated responses at the Schaffer collateral-CA1 synapse, a location at which neurotransmission has been shown to be modulated by mGluR7 activity. Thus, MMPIP and related compounds differentially inhibit coupling of mGluR7 in different cellular backgrounds and may not antagonize the coupling of this receptor to native G(i/o) signaling pathways in all cellular contexts. The pharmacology of this compound represents a striking example of the potential for context-dependent blockade of receptor responses by negative allosteric modulators.
Assuntos
Antagonistas de Aminoácidos Excitatórios/farmacologia , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Receptores de Glutamato Metabotrópico/fisiologia , Regulação Alostérica/efeitos dos fármacos , Regulação Alostérica/fisiologia , Animais , Linhagem Celular , Cricetinae , Regulação para Baixo/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologiaRESUMO
Muscarinic acetylcholine receptors (mAChRs) provide viable targets for the treatment of multiple central nervous system disorders. We have used cheminformatics and medicinal chemistry to develop new, highly selective M4 allosteric potentiators. VU10010, the lead compound, potentiates the M4 response to acetylcholine 47-fold while having no activity at other mAChR subtypes. This compound binds to an allosteric site on the receptor and increases affinity for acetylcholine and coupling to G proteins. Whole-cell patch clamp recordings revealed that selective potentiation of M4 with VU10010 increases carbachol-induced depression of transmission at excitatory but not inhibitory synapses in the hippocampus. The effect was not mimicked by an inactive analog of VU10010 and was absent in M4 knockout mice. Selective regulation of excitatory transmission by M4 suggests that targeting of individual mAChR subtypes could be used to differentially regulate specific aspects of mAChR modulation of function in this important forebrain structure.
Assuntos
Hipocampo/efeitos dos fármacos , Agonistas Muscarínicos/farmacologia , Antagonistas Muscarínicos/farmacologia , Receptor Muscarínico M4/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Transmissão Sináptica/efeitos dos fármacos , Regulação Alostérica , Sítio Alostérico , Animais , Células CHO , Cálcio/metabolismo , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Eletrofisiologia , Hipocampo/metabolismo , Humanos , Ligantes , Camundongos , Camundongos Knockout , Estrutura Molecular , Agonistas Muscarínicos/química , Antagonistas Muscarínicos/química , Ligação Proteica , Células Piramidais/efeitos dos fármacos , Células Piramidais/metabolismo , Ensaio Radioligante , Ratos , Receptor Muscarínico M4/agonistas , Receptor Muscarínico M4/antagonistas & inibidores , Receptor Muscarínico M4/genética , Bibliotecas de Moléculas Pequenas/química , Relação Estrutura-AtividadeRESUMO
Metabotropic glutamate (mGlu) receptors are family C G protein-coupled receptors (GPCRs) that modulate neuronal excitability and synaptic transmission throughout the nervous system. Owing to recent advances in development of subtype-selective allosteric modulators of mGlu receptors, individual members of the mGlu receptor family have been proposed as targets for treating a variety of neurological and psychiatric disorders, including substance use disorders. In this chapter, we highlight preclinical evidence that allosteric modulators of mGlu receptors could be useful for reducing alcohol consumption and preventing relapse in alcohol use disorder (AUD). We begin with an overview of the preclinical models that are used to study mGlu receptor involvement in alcohol-related behaviors. Alcohol exposure causes adaptations in both expression and function of various mGlu receptor subtypes, and pharmacotherapies aimed at reversing these adaptations have the potential to reduce alcohol consumption and seeking. Positive allosteric modulators (PAMs) of mGlu2 and negative allosteric modulators of mGlu5 show particular promise for reducing alcohol intake and/or preventing relapse. Finally, this chapter discusses important considerations for translating preclinical findings toward the development of clinically useful drugs, including the potential for PAMs to avoid tolerance issues that are frequently observed with repeated administration of GPCR agonists.