RESUMO
BACKGROUND: Breast cancer accounts for 7% of female cancer deaths, usually attributable to metastasis. While surgery is a mainstay of treatment, perioperative interventions may influence risk of metastasis during breast tumour resection. Amide local anaesthetics influence cancer cell biology via numerous mechanisms in vitro, but in vivo data is lacking. We aimed to test the hypothesis that perioperative lidocaine reduces pulmonary metastasis after inhalation and i.v. anaesthesia in the 4T1 murine breast cancer model. METHODS: 4T1 Cancer cells were injected into the mammary fat-pad of immunocompetent BALB/c female mice. After 7 days, the resultant tumour was excised under either sevoflurane or ketamine/xylazine anaesthesia with or without perioperative i.v. lidocaine (1.5 mg kg-1 bolus followed by 25 min infusion 2 mg kg-1 h-1). Fourteen days post-surgery, posthumous lung and liver specimens were examined for metastasis. Pro-inflammatory and pro-metastatic cytokines were profiled in post-mortem serum from a small number of the mice. RESULTS: Primary tumour diameter was similar between groups. Lidocaine reduced lung metastatic colony count vs sevoflurane alone; median (inter-quartile range) 0 (0-2) compared with 22.5 (0-481), P=0.02 and reduced the proportion of animals with pulmonary metastasis (28.5% compared with 52.5%, P=0.04). In mice receiving ketamine-xylazine, lidocaine did not decrease the overall colony count: 60 (26-123) compared with 23.5 (0-225), P=0.43, but increased the proportion of animals with pulmonary metastasis (100% compared with 50%, P<0.01). Post-mortem serum analysis demonstrated reduced pro-inflammatory and angiogenic cytokine expression in animals without metastasis which received lidocaine with sevoflurane. CONCLUSIONS: In this 4T1 murine model of breast cancer, lidocaine decreased pulmonary metastasis when combined with sevoflurane anaesthesia, perhaps via anti-inflammatory and anti-angiogenic effects. It had no such effect in mice given ketamine anaesthesia.
Assuntos
Agonistas alfa-Adrenérgicos , Anestésicos Dissociativos , Anestésicos Inalatórios , Anestésicos Locais/farmacologia , Ketamina , Lidocaína/farmacologia , Neoplasias Mamárias Experimentais/patologia , Neoplasias Mamárias Experimentais/cirurgia , Metástase Neoplásica/prevenção & controle , Sevoflurano , Xilazina , Animais , Linhagem Celular Tumoral , Citocinas/sangue , Feminino , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C , Neovascularização Patológica/patologia , Neovascularização Patológica/prevenção & controleRESUMO
In the present study, our aim was to investigate whether the novel highly selective 5-hydroxytryptamine6 (5-HT6) receptor antagonist SLV can ameliorate impairments in cognition and social interaction with potential relevance for both schizophrenia and Alzheimer's disease (AD). SLV sub-chronically - treated Wistar rats reared in isolation showed significantly enhanced prepulse inhibition (PPI) and object recognition performance when compared to vehicle - treated rats. In the isolated rats, also a significant reduction in expression of hippocampal neural cell adhesion molecule polysialylation (NCAM-PSA) was found which was ameliorated following treatment with SLV (30mg/kg). The social engagement deficit in rats exposed in utero (on gestational day 12.5) to valproic acid (VPA) was reversed by treatment with SLV (30mg/kg). SLV (20 and 30mg/kg, p.o.) fully reversed MK-801 - induced deficits in the ORT and also scopolamine - induced deficits in both the Object Recognition Task (ORT) and Object Location Task (OLT) in Wistar rats. In addition, a combination of sub-optimal doses of SLV and donepezil attenuated scopolamine-induced ORT deficits. Furthermore, SLV (10mg/kg, p.o.) reversed spontaneous alternation deficits in the T-maze induced by MK-801 administration in Swiss mice and in aged C57Bl/6J mice. SLV additionally improved T-Maze spatial learning and passive avoidance learning in Sprague-Dawley rats with amyoid-beta (Aß) injections into the hippocampus. In contrast, no benefits were found with SLV or the tested reference compounds (donepezil and RVT-101) on cognitive performance of 12months old Tg2576 mice. Also, in the social recognition task, an absence of cognitive enhancing properties was observed with SLV on "normal forgetting" in Wistar rats. Finally, analysis of spontaneous inhibitory postsynaptic currents (sIPSCs) frequency recorded from pyramidal cells revealed a reduction in the presence of 1µM of SLV. In conclusion, SLV was investigated in several rodent animal models and found to be effective at a least effective dose (LED) of 20mg/kg and 10mg/kg (p.o.) in the rat and the mouse, respectively.
Assuntos
Comportamento Animal/efeitos dos fármacos , Disfunção Cognitiva/tratamento farmacológico , Hipocampo/efeitos dos fármacos , Potenciais Pós-Sinápticos Inibidores/efeitos dos fármacos , Aprendizagem em Labirinto/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal/tratamento farmacológico , Inibição Pré-Pulso/efeitos dos fármacos , Células Piramidais/efeitos dos fármacos , Receptores de Serotonina , Reconhecimento Psicológico/efeitos dos fármacos , Antagonistas da Serotonina/farmacologia , Percepção Social , Fatores Etários , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Antagonistas da Serotonina/administração & dosagemRESUMO
Processing of information for long-term storage requires specific patterns of activity that lead to modification of synapse structure and eventual change in neural connectivity pattern. Morphological change associated with memory consolidation is reliant on neural cell adhesion molecule (NCAM) function and that of its polysialylated variant (NCAM PSA). Across species and paradigms, a transient frequency increase of polysialylated neurons in the hippocampal dentate has been found necessary for memory consolidation, however, recent studies suggest that NCAM PSA may serve to suppress memory formation in certain paradigms. As intraventricular infusions of NCAM blocking antibodies have been used successfully to demonstrate its time-dependent role at the 6 h post-training period of memory consolidation, we employed the same procedure to demonstrate a functional requirement for NCAM PSA in the consolidation of two commonly used behavioral paradigms: avoidance conditioning and spatial learning in Wistar rats. Anti-PSA was found to significantly induce amnesia of the passive avoidance response when infused at the 10 h post-training time, a period coincident with the learning-associated increase in dentate polysialylated cell frequency. Moreover, the amnesia became apparent at the 48 h recall time and was not apparent at the 24 h post-training time, suggesting a possible role in memory reconsolidation. A similar anti-PSA action was observed following water maze training in aged animals but was not apparent in young animals, an effect suggested to be due to inadequate antibody saturation of the polysialylated cell population. These studies confirm the requirement for NCAM PSA in memory consolidation and separate it from that of NCAM.
Assuntos
Anticorpos/farmacologia , Aprendizagem da Esquiva/efeitos dos fármacos , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/fisiopatologia , Molécula L1 de Adesão de Célula Nervosa/imunologia , Ácidos Siálicos/imunologia , Comportamento Espacial/efeitos dos fármacos , Fatores Etários , Animais , Comportamento Animal/efeitos dos fármacos , Hipocampo/citologia , Injeções Intraventriculares/métodos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Neurônios/metabolismo , Ratos , Ratos Wistar , Tempo de Reação/efeitos dos fármacosRESUMO
Polysialylation of neural cell adhesion molecule (NCAM PSA) modulates cell-cell homophilic binding and signalling during brain development and the remodelling of discrete brain regions in the adult. Following learning, a transient increase in the frequency of polysialylated neurones occurs in the dentate gyrus of the hippocampal formation, and this has been correlated with the selective retention and/or elimination of synapses that are transiently overproduced during memory consolidation. We now demonstrate that protein kinase C delta (PKCdelta) negatively regulates polysialyltransferase activity in the rat brain during development and also in the hippocampus during memory consolidation, where its down-regulation in the Golgi membrane fraction coincides with the transient increase in NCAM PSA expression. Decreased expression of PKCdelta was also observed in the hippocampus of rats reared in a complex environment and this directly contrasted the significant increase in frequency of hippocampal polysialylated neurones observed in these animals. These effects were isoform-specific as no change in total PKC enzyme activity was detected during memory consolidation and complex environment rearing had no effect on the hippocampal expression of PKCalpha, beta, gamma or epsilon. By sequential immunoprecipitation and immunoblot analysis, phosphorylation of polysialyltransferase protein(s) was (were) demonstrated to occur on both serine and tyrosine residues and this was associated with decreased enzyme activity. Moreover, a similar experimental approach revealed the degree of PKCdelta co-precipitation with polysialyltransferase protein(s) to be inversely correlated with polysialyltransferase activity. These findings support in vitro evidence indicating PKCdelta to regulate polysialyltransferase activity and NCAM polysialylation state.
Assuntos
Química Encefálica , Encéfalo/enzimologia , Isoenzimas/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Molécula L1 de Adesão de Célula Nervosa , Moléculas de Adesão de Célula Nervosa/biossíntese , Moléculas de Adesão de Célula Nervosa/metabolismo , Proteína Quinase C/fisiologia , Processamento de Proteína Pós-Traducional/fisiologia , Ácidos Siálicos/biossíntese , Ácidos Siálicos/metabolismo , Animais , Aprendizagem da Esquiva/fisiologia , Adesão Celular , Divisão Celular , Giro Denteado/metabolismo , Meio Ambiente , Ativação Enzimática , Glicosilação/efeitos dos fármacos , Complexo de Golgi/enzimologia , Hipocampo/metabolismo , Membranas Intracelulares/enzimologia , Masculino , Memória/fisiologia , Rememoração Mental/fisiologia , Camundongos , Neuroblastoma/patologia , Fosforilação , Fosfosserina/análise , Fosfotirosina/análise , Proteína Quinase C-delta , Ratos , Ratos Wistar , Tempo de Reação/fisiologia , Sialiltransferases/química , Sialiltransferases/metabolismo , Frações Subcelulares/enzimologia , Células Tumorais CultivadasRESUMO
2-N-Pentyl-4-pentynoic acid [pentyl-4-yn-valproic acid (VPA)] is an analogue of valproic acid that induces neuritogenesis and increases neural cell adhesion molecule (NCAM) prevalence in cultured neural cells. As memory consolidation involves synapse growth, aided by cell adhesion molecule function, we determined whether or not pentyl-4-yn-VPA had cognition-enhancing properties. Pentyl-4-yn-VPA (16-85 mg/kg) significantly improved water maze learning and task retention when given prior to each training session. Acute administration of pentyl-4-yn-VPA also influenced memory consolidation processes as, when given at 3 h post-passive avoidance training, the amnesia induced by scopolamine given 6 h post-training was prevented in a dose-dependent manner. Chronic administration of pentyl-4-yn-VPA (16.8 or 50.4 mg/kg) also significantly reduced escape latencies in the water maze task, 24 h following the last drug administration. This improved spatial learning was accompanied by enhanced neuroplasticity as the expression of NCAM polysialylated neurons in the infragranular zone of the dentate gyrus and in layer II of the perirhinal and piriform cortex was increased significantly following chronic drug treatment. The cognition-enhancing qualities of pentyl-4-yn-VPA, combined with its ability to attenuate the age-related loss of the NCAM polysialylation state, suggest that it may effectively slow the onset of cognitive decline.
Assuntos
Aprendizagem da Esquiva/fisiologia , Aprendizagem em Labirinto/fisiologia , Moléculas de Adesão de Célula Nervosa/metabolismo , Plasticidade Neuronal/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Lobo Temporal/efeitos dos fármacos , Ácido Valproico/farmacologia , Envelhecimento , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Linhagem Celular , Frequência Cardíaca/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Rim/anatomia & histologia , Rim/efeitos dos fármacos , Fígado/anatomia & histologia , Fígado/efeitos dos fármacos , Pulmão/anatomia & histologia , Pulmão/efeitos dos fármacos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Antagonistas Muscarínicos/farmacologia , Moléculas de Adesão de Célula Nervosa/química , Neurônios/metabolismo , Ligação Proteica , Ensaio Radioligante , Ratos , Ratos Wistar , Escopolamina/farmacologia , Lobo Temporal/metabolismo , Ácido Valproico/análogos & derivadosRESUMO
Transient and time-dependent modulations of neural cell adhesion molecule (NCAM) polysialylation in the dentate gyrus of the rodent hippocampus are a feature of spatial and nonspatial forms of learning. In the hippocampal formation, polysialic acid immunoreactivity was localized to granule-like cells and their mossy fibre axons. We now demonstrate the latter to extend to the CA3 region where apparent recurrent and Schaffer collaterals were labelled. The axons of the CA1 pyramidal cell layer were immunopositive, as was the subiculum that they innervate. Layers I and III of the entorhinal cortex stained intensely for polysialic acid; however, these were not visible in the more lateral aspect of this region and were replaced by a single band of immunopositive neurons that extended to include the perirhinal and piriform cortices. After Morris water maze training, the number of polysialylated neurons within the entorhinal cortex exhibited a two- to threefold increase at the 10-12-h posttraining time with respect to that observed immediately after training. This increase was task specific, as no change was observed in freely swimming animals or those required to locate a visible platform. These results suggest the presence of a corticohippocampal pathway involved in the eventual consolidation of memory.
Assuntos
Moléculas de Adesão Celular Neuronais/metabolismo , Hipocampo/metabolismo , Aprendizagem em Labirinto/fisiologia , Ácidos Siálicos/metabolismo , Lobo Temporal/metabolismo , Fatores Etários , Animais , Especificidade de Anticorpos , Córtex Entorrinal/química , Córtex Entorrinal/metabolismo , Hipocampo/química , Masculino , Vias Neurais/fisiologia , Polissacarídeos/análise , Polissacarídeos/imunologia , Polissacarídeos/metabolismo , Ratos , Ratos Wistar , Ácidos Siálicos/análise , Ácidos Siálicos/imunologia , Comportamento Espacial/fisiologia , Lobo Temporal/química , Fatores de TempoRESUMO
The neural cell adhesion molecule (NCAM) mediates cell adhesion and signal transduction through trans-homophilic- and/or cis-heterophilic-binding mechanisms. Intraventricular infusions of anti-NCAM have revealed a functional requirement of NCAM for the consolidation of memory in rats and chicks in a specific interval 6-8 h after training. We have now extended these studies to a synthetic peptide ligand of NCAM (C3) with an affinity for the IgI domain and the capability of inhibiting NCAM-mediated neurite outgrowth in vitro. Intraventricular administration of a single 5 microg bolus of C3 strongly inhibited recall of a passive avoidance response in adult rats, when given during training or in the 6-8-h posttraining period. The effect of C3 on memory consolidation was similar to that obtained with anti-NCAM as the amnesia was not observed until the 48-h recall time. The unique amnesic action of C3 during training could be related to disrupted NCAM internalization following training. In the 3-4-h posttraining period NCAM 180, the synapse-associated isoform, was down-regulated in the hippocampal dentate gyrus. This effect was mediated by ubiquitination and was prevented by C3 administration during training. These findings indicate NCAM to be involved in both the acquisition and consolidation of a passive avoidance response in the rat. Moreover, the study provides the first in vivo evidence for NCAM internalization in learning and identifies a synthetic NCAM ligand capable of modulating memory processes in vivo.
Assuntos
Aprendizagem da Esquiva/fisiologia , Endocitose/fisiologia , Imunoglobulina G/metabolismo , Moléculas de Adesão de Célula Nervosa/química , Moléculas de Adesão de Célula Nervosa/metabolismo , Animais , Sítios de Ligação/efeitos dos fármacos , Sítios de Ligação/imunologia , Química Encefálica/fisiologia , Complemento C3/metabolismo , Complemento C3/farmacologia , Condicionamento Psicológico/fisiologia , Injeções Intraventriculares , Ligantes , Masculino , Memória/fisiologia , Moléculas de Adesão de Célula Nervosa/imunologia , Neurônios/química , Neurônios/enzimologia , Ratos , Ratos Wistar , Tioléster Hidrolases/metabolismo , Ubiquitina Tiolesterase , Ubiquitinas/metabolismoRESUMO
Tacrine, one of the drugs available for Alzheimer's disease based on the cholinergic approach, suffers from considerable toxicity. Many analogues of tacrine have been prepared which retain the pharmacologically rich aminopyridine or aminoquinoline motifs. The current research was undertaken to produce an acetylcholinesterase inhibitor by employing 11-aminobenzoquinolizidines (4) and 10-aminobenzoindolizidines (5) as templates. Thus, we aimed to achieve three goals relative to tacrine: eliminate the pyridine and quinoline moieties and render the molecule less flat. Overall, the compounds we prepared were poorer inhibitors of acetylcholinesterase compared to tacrine. The single exception was compound 6f which exhibited an effect comparable to that of tacrine, but only at a dose of the order of 10(-3) M. However, despite the poor acetylcholinesterase inhibition by 6b, this compound proved to be an effective anti-amnesic agent at 45 mg/kg dose.
Assuntos
Nootrópicos/síntese química , Nootrópicos/farmacologia , Quinolizinas/síntese química , Quinolizinas/farmacologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Isomerismo , Espectroscopia de Ressonância Magnética , Masculino , Espectrometria de Massas , Nootrópicos/química , Quinolizinas/química , Ratos , Ratos Wistar , Tempo de Reação , Relação Estrutura-AtividadeRESUMO
Tacrine, one of the drugs available for Alzheimer's disease based on the cholinergic approach, suffers from considerable toxicity. Many analogues of tacrine has been prepared which retain the pharmacologically rich aminopyridine or aminoquinoline motifs. The current research is a continuation of our efforts in the area of 11-aminobenzoquinolizidines (4) and 10-aminobenzoindolizidines (5) (cf. ref9). A serendipitous discovery led us to the biologically active open chain analogue 9, and we proceeded to elaborate on this molecule. Overall, the compounds we prepared were poor inhibitors of acetylcholinesterase as compared to tacrine. The single exception was compound 20 which exhibited an effect comparable to that of tacrine, but only at a dose in the order of 10(-3) M. However, despite the poor acetylcholinesterase inhibition by 9, this compound was found to be an effective antiamnesic agent.