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1.
Development ; 151(20)2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38895900

RESUMO

Tunicates are the sister group to the vertebrates, yet most species have a life cycle split between swimming larva and sedentary adult phases. During metamorphosis, larval neurons are replaced by adult-specific ones. The regulatory mechanisms underlying this replacement remain largely unknown. Using tissue-specific CRISPR/Cas9-mediated mutagenesis in the tunicate Ciona, we show that orthologs of conserved hindbrain and branchiomeric neuron regulatory factors Pax2/5/8 and Phox2 are required to specify the 'neck', a cellular compartment set aside in the larva to give rise to cranial motor neuron-like neurons post-metamorphosis. Using bulk and single-cell RNA-sequencing analyses, we characterize the transcriptome of the neck downstream of Pax2/5/8. We present evidence that neck-derived adult ciliomotor neurons begin to differentiate in the larva and persist through metamorphosis, contrary to the assumption that the adult nervous system is formed after settlement and the death of larval neurons during metamorphosis. Finally, we show that FGF signaling during the larval phase alters the patterning of the neck and its derivatives. Suppression of FGF converts neck cells into larval neurons that fail to survive metamorphosis, whereas prolonged FGF signaling promotes an adult neural stem cell-like fate.


Assuntos
Larva , Metamorfose Biológica , Animais , Larva/crescimento & desenvolvimento , Neurônios/metabolismo , Neurônios/citologia , Fatores de Crescimento de Fibroblastos/metabolismo , Fatores de Crescimento de Fibroblastos/genética , Regulação da Expressão Gênica no Desenvolvimento , Neurônios Motores/metabolismo , Neurônios Motores/citologia , Transdução de Sinais/genética , Ciona intestinalis/genética , Sobrevivência Celular , Transcriptoma/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Sistemas CRISPR-Cas/genética
2.
Dev Biol ; 500: 1-9, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37209936

RESUMO

ARL13B is a small GTPase enriched in cilia. Deletion of Arl13b in mouse kidney results in renal cysts and an associated absence of primary cilia. Similarly, ablation of cilia leads to kidney cysts. To investigate whether ARL13B functions from within cilia to direct kidney development, we examined kidneys of mice expressing an engineered cilia-excluded ARL13B variant, ARL13BV358A. These mice retained renal cilia and developed cystic kidneys. Because ARL13B functions as a guanine nucleotide exchange factor (GEF) for ARL3, we examined kidneys of mice expressing an ARL13B variant that lacks ARL3 GEF activity, ARL13BR79Q. We found normal kidney development with no evidence of cysts in these mice. Taken together, our results show that ARL13B functions within cilia to inhibit renal cystogenesis during mouse development, and that this function does not depend on its role as a GEF for ARL3.


Assuntos
Doenças Renais Císticas , Rim , Animais , Camundongos , Fatores de Ribosilação do ADP/genética , Fatores de Ribosilação do ADP/metabolismo , Cílios/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Rim/metabolismo , Doenças Renais Císticas/genética
3.
Eur J Neurosci ; 53(3): 841-851, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33617053

RESUMO

The hippocampus has been implicated in the processing and storage of aversive memories but the precise mechanisms by which these memories persist in time remain elusive. We have demonstrated that dopaminergic neurotransmission in the dorsal hippocampus regulates the long-term storage of both appetitive and aversive memories at a critical time point known as "late consolidation" (12 hr after the learning experience). This modulation appears to have opposite effects depending on the valence of the stimuli, with hippocampal dopamine release peaking immediately and 13-17 hr after a rewarding experience. Here, we determined the release pattern of hippocampal dopamine following an aversive experience, in order to better understand this opposite modulation process. We observed significant increases in dopamine levels at several times (6-8, 11-12, and 15 hr) after subjecting rats to a conditioned place aversion (CPA) task with the aversive agent lithium chloride (LiCl). Early pharmacological blockade of hippocampal DA receptors impaired CPA memory consolidation. In addition and consistent with previous findings showing that late post-training infusions of dopaminergic agents into the hippocampus modulate the long-term storage of aversive memories, we found that the photostimulation of dopaminergic VTA fibers in the dorsal hippocampus 11-12 hr after CPA training was enough to transform a short-lasting long-term memory into a long-lasting one. The fact that the persistence of an aversive memory can still be affected several hours after the learning experience opens new avenues to develop behavioral and pharmacological strategies for the treatment of a variety of mental disorders.


Assuntos
Dopamina , Consolidação da Memória , Animais , Aprendizagem da Esquiva , Hipocampo , Memória , Ratos , Transmissão Sináptica
4.
Dev Biol ; 437(2): 152-162, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29571613

RESUMO

Smoothened (Smo) is the essential transducer of Sonic hedgehog (Shh) signaling, which regulates cell fate and proliferation during embryogenesis. We identified a novel mouse mutant, cabbie (cbb), and found that its cause is a missense mutation in Smo. We showed the Smocbb mutation is insensitive to the Shh agonist SAG, perhaps due to the disruption of SAG binding. We characterized Smocbb for defects in craniofacial and skeletal development, as well as neural tube patterning, and revealed Smocbb affected processes that require the highest levels of Shh activity. Smo is normally enriched in cilia upon Shh stimulation; however, we detected inefficient enrichment of Smo in Smocbb mutants whether we stimulated with Shh or SAG. Taken together, our data suggest that the highest levels of vertebrate Hedgehog signaling activity require efficient Smo ciliary enrichment.


Assuntos
Cílios/metabolismo , Proteínas Hedgehog/metabolismo , Receptor Smoothened/genética , Animais , Padronização Corporal/genética , Técnicas de Cultura de Células , Camundongos , Mutação , Organogênese/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Vertebrados/metabolismo
5.
J Neurosci ; 35(8): 3460-9, 2015 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-25716845

RESUMO

The lateral habenula (LHb) is involved in reward and aversion and is reciprocally connected with dopamine (DA)-containing brain regions, including the ventral tegmental area (VTA). We used a multidisciplinary approach to examine the properties of DA afferents to the LHb in the rat. We find that >90% of VTA tyrosine hydroxylase (TH) neurons projecting to the LHb lack vesicular monoamine transporter 2 (VMAT2) mRNA, and there is little coexpression of TH and VMAT2 protein in this mesohabenular pathway. Consistent with this, electrical stimulation of LHb did not evoke DA-like signals, assessed with fast-scan cyclic voltammetry. However, electrophysiological currents that were inhibited by L741,742, a DA-D4-receptor antagonist, were observed in LHb neurons when DA uptake or degradation was blocked. To prevent DA activation of D4 receptors, we repeated this experiment in LHb slices from DA-depleted rats. However, this did not disrupt D4 receptor activation initiated by the dopamine transporter inhibitor, GBR12935. As the LHb is also targeted by noradrenergic afferents, we examined whether GBR12935 activation of DA-D4 receptors occurred in slices depleted of norepinephrine (NE). Unlike DA, NE depletion prevented the activation of DA-D4 receptors. Moreover, direct application of NE elicited currents in LHb neurons that were blocked by L741,742, and GBR12935 was found to be a more effective blocker of NE uptake than the NE-selective transport inhibitor nisoxetine. These findings demonstrate that NE is released in the rat LHb under basal conditions and that it activates DA-D4 receptors. Therefore, NE may be an important regulator of LHb function.


Assuntos
Habenula/metabolismo , Norepinefrina/farmacologia , Receptores de Dopamina D4/metabolismo , Animais , Dopamina/metabolismo , Dopamina/farmacologia , Agonistas de Dopamina/farmacologia , Antagonistas de Dopamina/farmacologia , Proteínas da Membrana Plasmática de Transporte de Dopamina/antagonistas & inibidores , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/fisiologia , Habenula/citologia , Habenula/fisiologia , Isoxazóis/farmacologia , Masculino , Norepinefrina/metabolismo , Piperazinas/farmacologia , Piperidinas/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Dopamina D4/antagonistas & inibidores , Área Tegmentar Ventral/citologia , Área Tegmentar Ventral/metabolismo , Área Tegmentar Ventral/fisiologia , Proteínas Vesiculares de Transporte de Monoamina/genética , Proteínas Vesiculares de Transporte de Monoamina/metabolismo
6.
Alcohol Clin Exp Res ; 40(2): 301-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26842249

RESUMO

BACKGROUND: Ethanol is widely known for its depressant effects; however, the underlying neurobiological mechanisms are not clear. Calcium-activated anion channels (CAACs) contribute to extracellular chloride levels and thus may be involved in regulating inhibitory mechanisms within the central nervous system. Therefore, we hypothesized that CAACs influence ethanol behavioral sensitivity by altering CAAC expression. METHODS: We assessed the role of CAACs in ethanol-induced loss of righting reflex (LORR) and locomotor activity using intracerebroventricular infusions of several nonselective CAAC blockers. CAAC expression was determined after ethanol exposure. RESULTS: Ethanol-induced LORR (4.0 g/kg, intraperitoneally [i.p.]) was significantly attenuated by all 4 CAAC blockers. Blocking CAACs did not impact ethanol's low-dose (1.5 g/kg, i.p.) locomotor-impairing effects. Biochemical analysis of CAAC protein expression revealed that cortical Bestrophin1 (Best1) and Tweety1 levels were reduced as early as 30 minutes following a single ethanol injection (3.5 g/kg, intraperitoneally [i.p.]) and remained decreased 24 hours later in P2 fractions. Cortical Best1 levels were also reduced following 1.5 g/kg. However, CAAC expression was unaltered in the striatum following a single ethanol exposure. Ethanol did not affect Tweety2 levels in either brain region. CONCLUSIONS: These results suggest that CAACs are a major target of ethanol in vivo, and the regulation of these channels contributes to select behavioral actions of ethanol.


Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Etanol/farmacologia , Hipnóticos e Sedativos/antagonistas & inibidores , Ácido 4,4'-Di-Isotiocianoestilbeno-2,2'-Dissulfônico/farmacologia , Animais , Western Blotting , Química Encefálica/efeitos dos fármacos , Canais de Cálcio/análise , Etanol/antagonistas & inibidores , Ácido Flufenâmico/farmacologia , Hipnóticos e Sedativos/farmacologia , Masculino , Atividade Motora/efeitos dos fármacos , Ácido Niflúmico/farmacologia , Nitrobenzoatos/farmacologia , Ratos , Ratos Sprague-Dawley , Reflexo de Endireitamento/efeitos dos fármacos
8.
bioRxiv ; 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-36798281

RESUMO

ARL13B is a small GTPase enriched in cilia. Deletion of Arl13b in mouse kidney results in renal cysts and an associated absence of primary cilia. Similarly, ablation of cilia leads to kidney cysts. To investigate whether ARL13B functions from within cilia to direct kidney development, we examined kidneys of mice expressing an engineered cilia-excluded ARL13B variant, ARL13BV358A. These mice retained renal cilia and developed cystic kidneys. Because ARL13B functions as a guanine nucleotide exchange factor (GEF) for ARL3, we examined kidneys of mice expressing an ARL13B variant that lacks ARL3 GEF activity, ARL13BR79Q. We found normal kidney development with no evidence of cysts in these mice. Taken together, our results show that ARL13B functions within cilia to inhibit renal cystogenesis during mouse development, and that this function does not depend on its role as a GEF for ARL3.

9.
bioRxiv ; 2023 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-37577625

RESUMO

Cilia are near ubiquitous small, cellular appendages critical for cell-to-cell communication. As such, they are involved in diverse developmental and homeostatic processes, including energy homeostasis. ARL13B is a regulatory GTPase highly enriched in cilia. Mice expressing an engineered ARL13B variant, ARL13BV358A which retains normal biochemical activity, display no detectable ciliary ARL13B. Surprisingly, these mice become obese. Here, we measured body weight, food intake, and blood glucose levels to reveal these mice display hyperphagia and metabolic defects. We showed that ARL13B normally localizes to cilia of neurons in specific brain regions and pancreatic cells but is excluded from these cilia in the Arl13bV358A/V358A model. In addition to its GTPase function, ARL13B acts as a guanine nucleotide exchange factor (GEF) for ARL3. To test whether ARL13B's GEF activity is required to regulate body weight, we analyzed the body weight of mice expressing ARL13BR79Q, a variant that lacks ARL13B GEF activity for ARL3. We found no difference in body weight. Taken together, our results show that ARL13B functions within cilia to control body weight and that this function does not depend on its role as a GEF for ARL3. Controlling the subcellular localization of ARL13B in the engineered mouse model, ARL13BV358A, enables us to define the cilia-specific role of ARL13B in regulating energy homeostasis.

10.
bioRxiv ; 2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37645866

RESUMO

Tunicates are the sister group to the vertebrates, yet most species have a life cycle split between swimming larva and sedentary adult phases. During metamorphosis, larval neurons are largely replaced by adult-specific ones. Yet the regulatory mechanisms underlying this neural replacement remain largely unknown. Using tissue-specific CRISPR/Cas9-mediated mutagenesis in the tunicate Ciona, we show that orthologs of conserved hindbrain and branchiomeric neuron regulatory factors Pax2/5/8 and Phox2 are required to specify the "Neck", a compartment of cells set aside in the larva to give rise to cranial motor neuron-like neurons in the adult. Using bulk and single-cell RNAseq analyses, we also characterize the transcriptome of the Neck downstream of Pax2/5/8. Surprisingly, we find that Neck-derived adult ciliomotor neurons begin to differentiate in the larva, contrary to the long-held assumption that the adult nervous system is formed only after settlement and the death of larval neurons during metamorphosis. Finally, we show that manipulating FGF signaling during the larval phase alters the patterning of the Neck and its derivatives. Suppression of FGF converts Neck cells into larval neurons that fail to survive metamorphosis, while prolonged FGF signaling promotes an adult neural stem cell-like fate instead.

11.
Alcohol Clin Exp Res ; 35(7): 1246-55, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21410484

RESUMO

BACKGROUND: Tolerance to the behavioral and subjective effects of alcohol (ethanol) is thought to be a major predictive factor for the development of alcoholism. Evidence from rodent models has supported this view with those animals most likely to develop tolerance generally drinking and preferring ethanol more so than those resistant to it. Despite this evidence, very little is known about the behavioral relationships between ethanol-induced tolerance and consumption. The goal of this study was to evaluate the development of tolerance to the ataxic effects of ethanol using a mouse model of binge-like intake dubbed "Drinking in the Dark" (DID; Physiol Behav 2005, 84:53-63). We hypothesized that mice would become tolerant to the ataxic effects of ethanol as this behavior is known to be altered at the blood ethanol concentrations reached using this model (≥80 mg/dl). METHODS: To evaluate this, we gave daily DID ethanol or water access sessions to male C57BL/6J (B6) mice and monitored ataxia (and in some cases locomotion) at various time points. RESULTS: In general, mice given 14 consecutive days of ethanol access displayed tolerance to the ataxic effects of ethanol compared to water-drinking controls. These effects were coupled with alterations in locomotor behavior and in some cases differences in ethanol pharmacokinetics. CONCLUSIONS: Thus, we can conclude that tolerance to the behavioral effects of binge-like ethanol intake might play a key role in the daily maintenance of this behavior and that these effects may be evidence of important neuroadaptations involved in the development of alcoholism.


Assuntos
Ataxia/induzido quimicamente , Escuridão , Tolerância a Medicamentos , Etanol/intoxicação , Modelos Animais , Atividade Motora/efeitos dos fármacos , Consumo de Bebidas Alcoólicas/fisiopatologia , Consumo de Bebidas Alcoólicas/psicologia , Animais , Ataxia/fisiopatologia , Ataxia/psicologia , Tolerância a Medicamentos/fisiologia , Etanol/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/fisiologia
12.
Curr Biol ; 31(2): R80-R82, 2021 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-33497637

RESUMO

Recent work has resolved the established links between ß-arrestin 2 and the BBSome in controlling ciliary GPCR localization by showing that ß-arrestin 2 regulates the addition of K63-linked ubiquitin chains to tag proteins for removal from the cilia via the BBSome.


Assuntos
Cílios , Proteínas , Biologia
13.
Mol Biol Cell ; 32(8): 800-822, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33596093

RESUMO

ELMOD2 is a GTPase-activating protein with uniquely broad specificity for ARF family GTPases. We previously showed that it acts with ARL2 in mitochondrial fusion and microtubule stability and with ARF6 during cytokinesis. Mouse embryonic fibroblasts deleted for ELMOD2 also displayed changes in cilia-related processes including increased ciliation, multiciliation, ciliary morphology, ciliary signaling, centrin accumulation inside cilia, and loss of rootlets at centrosomes with loss of centrosome cohesion. Increasing ARL2 activity or overexpressing Rootletin reversed these defects, revealing close functional links between the three proteins. This was further supported by the findings that deletion of Rootletin yielded similar phenotypes, which were rescued upon increasing ARL2 activity but not ELMOD2 overexpression. Thus, we propose that ARL2, ELMOD2, and Rootletin all act in a common pathway that suppresses spurious ciliation and maintains centrosome cohesion. Screening a number of markers of steps in the ciliation pathway supports a model in which ELMOD2, Rootletin, and ARL2 act downstream of TTBK2 and upstream of CP110 to prevent spurious release of CP110 and to regulate ciliary vesicle docking. These data thus provide evidence supporting roles for ELMOD2, Rootletin, and ARL2 in the regulation of ciliary licensing.


Assuntos
Cílios/metabolismo , Proteínas do Citoesqueleto/metabolismo , Fatores de Ribosilação do ADP/metabolismo , Fatores de Ribosilação do ADP/fisiologia , Animais , Linhagem Celular , Centrossomo/metabolismo , Cílios/fisiologia , Citocinese , Proteínas do Citoesqueleto/fisiologia , Fibroblastos/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Humanos , Camundongos , Microtúbulos/metabolismo , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/fisiologia , Transdução de Sinais
14.
Wiley Interdiscip Rev Dev Biol ; 9(6): e377, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32084300

RESUMO

Cilia are microtubule-based, cell-surface projections whose machinery is evolutionarily conserved. In vertebrates, cilia are observed on almost every cell type and are either motile or immotile. Immotile sensory, or primary cilia, are responsive to extracellular ligands and signals. Cilia can be thought of as compartments, functionally distinct from the cell that provides an environment for signaling cascades. Hedgehog is a critical developmental signaling pathway which is functionally linked to primary cilia in vertebrates. The major components of the vertebrate Hedgehog signaling pathway dynamically localize to the ciliary compartment and ciliary membrane. Critically, G-protein coupled receptor (GPCR) Smoothened, the obligate transducer of the pathway, is enriched and activated in the cilium. While Smoothened is the most intensely studied ciliary receptor, many GPCRs localize within cilia. Understanding the link between Smoothened and cilia defines common features, and distinctions, of GPCR signaling within the primary cilium. This article is categorized under: Signaling Pathways > Global Signaling Mechanisms Signaling Pathways > Cell Fate Signaling.


Assuntos
Cílios/genética , Proteínas Hedgehog/genética , Receptores Acoplados a Proteínas G/genética , Receptor Smoothened/genética , Animais , Cílios/patologia , Humanos , Transdução de Sinais , Vertebrados/genética
15.
Elife ; 92020 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-32129762

RESUMO

ARL13B is a regulatory GTPase highly enriched in cilia. Complete loss of Arl13b disrupts cilia architecture, protein trafficking and Sonic hedgehog signaling. To determine whether ARL13B is required within cilia, we knocked in a cilia-excluded variant of ARL13B (V358A) and showed it retains all known biochemical function. We found that ARL13BV358A protein was expressed but could not be detected in cilia, even when retrograde ciliary transport was blocked. We showed Arl13bV358A/V358A mice are viable and fertile with normal Shh signal transduction. However, in contrast to wild type cilia, Arl13bV358A/V358A cells displayed short cilia and lacked ciliary ARL3 and INPP5E. These data indicate that ARL13B's role within cilia can be uncoupled from its function outside of cilia. Furthermore, these data imply that the cilia defects upon complete absence of ARL13B do not underlie the alterations in Shh transduction, which is unexpected given the requirement of cilia for Shh transduction.


Assuntos
Fatores de Ribosilação do ADP/genética , Fatores de Ribosilação do ADP/metabolismo , Cílios/metabolismo , Proteínas Hedgehog/metabolismo , Transdução de Sinais , Sequência de Aminoácidos , Animais , Sequência de Bases , Sistemas CRISPR-Cas , Desenvolvimento Embrionário/genética , Edição de Genes , Expressão Gênica , Camundongos , Camundongos Knockout , Mutação , Fenótipo
16.
Cell Rep ; 29(11): 3356-3366.e3, 2019 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-31825820

RESUMO

The small GTPase Arl13b is enriched in primary cilia and regulates Sonic hedgehog (Shh) signaling. During neural development, Shh controls patterning and proliferation through a canonical, transcription-dependent pathway that requires the primary cilium. Additionally, Shh controls axon guidance through a non-canonical, transcription-independent pathway whose connection to the primary cilium is unknown. Here we show that inactivation of Arl13b results in defective commissural axon guidance in vivo. In vitro, we demonstrate that Arl13b functions autonomously in neurons for their Shh-dependent guidance response. We detect Arl13b protein in axons and growth cones, far from its well-established ciliary enrichment. To test whether Arl13b plays a non-ciliary function, we used an engineered, cilia-localization-deficient Arl13b variant and found that it was sufficient to mediate Shh axon guidance in vitro and in vivo. Together, these results indicate that, in addition to its ciliary role in canonical Shh signaling, Arl13b plays a cilia-independent role in Shh-mediated axon guidance.


Assuntos
Fatores de Ribosilação do ADP/metabolismo , Orientação de Axônios , Cílios/metabolismo , Proteínas Hedgehog/metabolismo , Animais , Células Cultivadas , Cones de Crescimento/metabolismo , Camundongos , Transdução de Sinais
17.
Dev Psychobiol ; 50(6): 566-78, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18683190

RESUMO

Animal models of prenatal ethanol exposure are necessary to more fully understand the effects of ethanol on the developing embryo/fetus. However, most models employ procedures that may produce additional maternal stress beyond that produced by ethanol alone. We employed a daily limited-access ethanol intake model called Drinking in the Dark (DID) to assess the effects of voluntary maternal binge-like ethanol intake on the developing mouse. Evidence suggests that binge exposure may be particularly harmful to the embryo/fetus, perhaps due to the relatively higher blood ethanol concentrations achieved. Pregnant females had mean daily ethanol intakes ranging from 4.2 to 6.4 g/kg ethanol over gestation, producing blood ethanol concentrations ranging from 115 to 182 mg/dL. This level of ethanol intake produced behavioral alterations among adolescent offspring that disappeared by adulthood, including altered sensitivity to ethanol's hypnotic actions. The DID model may provide a useful tool for studying the effects of prenatal ethanol exposure in mice.


Assuntos
Consumo de Bebidas Alcoólicas/sangue , Alcoolismo/sangue , Escuridão , Etanol/administração & dosagem , Etanol/sangue , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Animais , Ansiedade/induzido quimicamente , Ansiedade/diagnóstico , Comportamento Animal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Ritmo Circadiano , Modelos Animais de Doenças , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Masculino , Comportamento Materno/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal/sangue , Reflexo/efeitos dos fármacos , Distribuição por Sexo , Água/administração & dosagem
18.
PLoS One ; 11(7): e0158885, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27387668

RESUMO

Electrical stimulation of the lateral hypothalamus can motivate feeding or can serve as a reward in its own right. It remains unclear whether the same or independent but anatomically overlapping circuitries mediate the two effects. Electrical stimulation findings implicate medial forebrain bundle (MFB) fibers of passage in both effects, and optogenetic studies confirm a contribution from fibers originating in the lateral hypothalamic area and projecting to or through the ventral tegmental area. Here we report that optogenetic activation of ventral tegmental fibers from cells of origin in more anterior or posterior portions of the MFB failed to induce either reward or feeding. The feeding and reward induced by optogenetic activation of fibers from the lateral hypothalamic cells of origin were influenced similarly by variations in stimulation pulse width and pulse frequency, consistent with the hypothesis of a common substrate for the two effects. There were, however, several cases where feeding but not self-stimulation or self-stimulation but not feeding were induced, consistent with the hypothesis that distinct but anatomically overlapping systems mediate the two effects. Thus while optogenetic stimulation provides a more selective tool for characterizing the mechanisms of stimulation-induced feeding and reward, it does not yet resolve the question of common or independent substrates.


Assuntos
Estimulação Elétrica , Região Hipotalâmica Lateral/fisiologia , Hipotálamo/fisiologia , Recompensa , Autoestimulação/fisiologia , Área Tegmentar Ventral/fisiologia , Animais , Impulso (Psicologia) , Neurônios GABAérgicos/metabolismo , Masculino , Feixe Prosencefálico Mediano , Vias Neurais/fisiologia , Neurônios/metabolismo , Optogenética , Ratos , Ratos Sprague-Dawley
19.
Neuropsychopharmacology ; 40(11): 2614-22, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25881115

RESUMO

The OPRM1 A118G polymorphism is the most widely studied µ-opioid receptor (MOR) variant. Although its involvement in acute alcohol effects is well characterized, less is known about the extent to which it alters responses to opioids. Prior work has shown that both electrophysiological and analgesic responses to morphine but not to fentanyl are moderated by OPRM1 A118G variation, but the mechanism behind this dissociation is not known. Here we found that humanized mice carrying the 118GG allele (h/mOPRM1-118GG) were less sensitive than h/mOPRM1-118AA littermates to the rewarding effects of morphine and hydrocodone but not those of other opioids measured with intracranial self-stimulation. Reduced morphine reward in 118GG mice was associated with decreased dopamine release in the nucleus accumbens and reduced effects on GABA release in the ventral tegmental area that were not due to changes in drug potency or efficacy in vitro or receptor-binding affinity. Fewer MOR-binding sites were observed in h/mOPRM1-118GG mice, and pharmacological reduction of MOR availability unmasked genotypic differences in fentanyl sensitivity. These findings suggest that the OPRM1 A118G polymorphism decreases sensitivity to low-potency agonists by decreasing receptor reserve without significantly altering receptor function.


Assuntos
Analgésicos Opioides/farmacologia , Núcleo Accumbens/metabolismo , Receptores Opioides mu/metabolismo , Recompensa , Área Tegmentar Ventral/metabolismo , Animais , Modelos Animais de Doenças , Dopamina/metabolismo , Células HEK293 , Humanos , Masculino , Camundongos Transgênicos , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Antagonistas de Entorpecentes/farmacologia , Núcleo Accumbens/efeitos dos fármacos , Polimorfismo de Nucleotídeo Único , Receptores Opioides mu/genética , Autoestimulação , Técnicas de Cultura de Tecidos , Área Tegmentar Ventral/efeitos dos fármacos , Ácido gama-Aminobutírico/metabolismo
20.
Alcohol ; 48(5): 463-70, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24874150

RESUMO

Adolescent rats display reduced sensitivity to many dysphoria-related effects of alcohol (ethanol) including motor ataxia and sedative hypnosis, but the underlying neurobiological factors that contribute to these differences remain unknown. The cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) pathway, particularly the type II regulatory subunit (RII), has been implicated in ethanol-induced molecular and behavioral responses in adults. Therefore, the current study examined cerebral cortical PKA in adolescent and adult ethanol responses. With the exception of early adolescence, PKA RIIα and RIIß subunit levels largely did not differ from adult levels in either whole cell lysate or P2 synaptosomal expression. However, following acute ethanol exposure, PKA RIIß P2 synaptosomal expression and activity were increased in adults, but not in adolescents. Behaviorally, intracerebroventricular administration of the PKA activator Sp-cAMP and inhibitor Rp-cAMP prior to ethanol administration increased adolescent sensitivity to the sedative-hypnotic effects of ethanol compared to controls. Sp-cAMP was ineffective in adults whereas Rp-cAMP suggestively reduced loss of righting reflex (LORR) with paralleled increases in blood ethanol concentrations. Overall, these data suggest that PKA activity modulates the sedative/hypnotic effects of ethanol and may potentially play a wider role in the differential ethanol responses observed between adolescents and adults.


Assuntos
Subunidade RIIbeta da Proteína Quinase Dependente de AMP Cíclico/metabolismo , Etanol/farmacologia , Envelhecimento , Animais , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Subunidade RIIalfa da Proteína Quinase Dependente de AMP Cíclico/biossíntese , Masculino , Ratos Sprague-Dawley , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
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