(in English): The aim of the work was to perform in-depth analysis of M2KO mice both at baseline and upon a challenge with a cold stress and to explore the role of opposing receptors (i.e. adrenoceptors) in adaptation to lacking M2-receptors in the heart. We have performed receptor binding studies, study of receptor gene expression, echocardiography, telemetric monitoring of heart rate, body temperature and activity, heart rate variability and biorhythm analysis, analysis of heart rate response to the application of drugs (carbachol, atropine, isoprenaline, propranolol), assessment of adenylyl cyclase and NO synthase activity, measurement of catecholamine blood concentration and gene expression of catecholamine-synthesizing enzymes. We have found that the disruption of M2-receptor gene caused a compensatory decrease of cardiostimulatory β1-adrenoceptors and β2-adrenoceptors with corresponding down-regulation of the gene expression, M3-receptors were down-regulated as well. Missing M2-receptors were functionally replaced by the main cardioinhibitory β3-adrenoceptors that were up-regulated, not by cardioinhibitory M4-receptors. β3-adrenoceptors were found to signal through adenylyl cyclase instead of NO synthase. All these changes were found in the left ventricle only, so heterologous regulation is...

Orientadores: Antonio Carlos Boschero, Kleber Luiz de Araujo e Souza / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-13T04:48:49Z (GMT). No. of bitstreams: 1 Paula_FlaviaMariaMourade_M.pdf: 2651405 bytes, checksum: 255d59533f2d09ff678a30dd27fdc45f (MD5) Previous issue date: 2009 / Resumo: INGAP (Islet Neogenesis Associated Protein), um peptídeo primeiramente dentificado em hamsters, cujo pâncreas foi previamente embrulhado em papel celofane, tem como função principal induzir neogênese e diferenciação de células beta pancreáticas, além de melhorar a secreção de insulina induzida por glicose e aminoácidos. Existem poucas informações a respeito dos mecanismos intracelulares desencadeados pelo INGAP em células beta. Assim, este trabalho teve como objetivo estudar tais mecanismos em 2 linhagens de células beta pancreáticas produtoras de insulina, denominadas RINm5F e MIN6. Para isso foi utilizado o INGAP-PP (INGAP104-118) constituído por uma seqüência de 15 aminoácidos e que mantém as mesmas propriedades da molécula do INGAP. Durante o procedimento experimental foi realizado um "screening" dos elementos responsivos a alguns fatores de transcrição. A expressão de algumas proteínas como receptor muscarínico M3, p85, AKT, p70S6k, PCNA e NF?B foi analisada, assim como a secreção de insulina estimulada por glicose, a mobilização de cálcio intracelular e a medida de viabilidade celular. A exposição das células MIN6 ao INGAP-PP aumentou a secreção de insulina induzida por glicose assim como a mobilização intracelular de cálcio. INGAP-PP ativou os fatores de transcrição c-Myc, SRE e em especial o NF?B nas duas linhagens celulares. A viabilidade celular também foi aumentada nas células expostas ao INGAP-PP a qual foi acompanhada de aumento na expressão de PCNA, proteína diretamente relacionada com a progressão do ciclo celular. Ainda, a expressão protéica do receptor muscarínico M3 foi aumentada na presença de INGAP-PP. Esse efeito foi bloqueado pela pré-exposição das células a um inibidor farmacológico do NF?B. Pode-se concluir que a ativação moderada do c-Myc e o aumento na expressão de PCNA estão relacionados com o aumento na viabilidade celular. Adicionalmente, conclui-se que a ativação moderada do NF?B induzida pelo INGAP-PP controla direta ou indiretamente a expressão do receptor M3 e tal processo pode estar relacionado sinergicamente com o aumento na proliferação celular. / Abstract: The pentadecapeptide comprising the 104-118 aminoacid sequence of the ilotropin-derived Reg3- related islet neogenesis associated protein (INGA-PP) has been implicated in pancreatic beta-cell neogenesis and enhancement of the insulin secretion in pancreatic islets. There is little information regarding the mechanism of action of the polypeptide. The aim of this study was to investigate intracellular pathways by which INGAP-PP signs insulin-producing cells. The results show that INGAP-PP increased the insulin secretion and induced mobilization of intracellular calcium in MIN6 cells. INGAP-PP exposure activated c-Myc, serum response element (SRE) and particularly nuclear factor kappa B (NF?B) in both MIN6 and RINm5F insulin-producing cells. There was an increase in the proliferation rate of viable cells that was accompanied by an increase in the proliferating cell nuclear antigen (PCNA) protein expression following INGAP-PP treatment. In addition, INGAP-PP increased the expression of the muscarinic M3 receptor subtype. This effect was impaired by blocking NF?B signaling pathway. Cells incubated in the presence of foetal calf serum (FCS) also showed increased M3 receptor expression. In conclusion, these data show that activation of c-Myc signaling pathway and increased PCNA expression might be involved in the increased proliferation rate of insulin-producing cells following incubation with INGAP-PP. NF?B signaling plays an essential role in controlling the expression of the acetylcholine M3 receptor. / Mestrado / Fisiologia / Mestre em Biologia Funcional e Molecular

Sabendo-se que o sistema colinérgico muscarínico modula funções cognitivas, propomos estudar as toxinas muscarínicas isoladas do veneno da M. lemniscatus, MT-Mlα e MT-Mlβ, sobre o processo de aprendizado e memória. Ratos Wistar machos foram injetados por via intrahipocampal com MT-Mlα, MT-Mlβ ou solução de Ringer (SRg). Após um período de sete dias de treino no Labirinto Aquático de Morris (LAM), os ratos receberam uma das toxinas ou SRg (dia da inoculação) e 20 min e 24 h após a inoculação foram testados no LAM. A MT-Mlα reduziu o tempo de permanência no quadrante do dia anterior, indicando interferência na evocação da memória. Por outro lado, a MT-Mlβ causou um efeito facilitatório quanto à recuperação da localização da plataforma. A ansiedade foi avaliada no Labirinto em Cruz Elevado, o treino foi feito após 30 min da injeção e o teste 24 h após. O tratamento com a MT-Mlβ mostrou ter um efeito ansiogênico, o que pode ter contribuído para o efeito facilitatório sobre a memória, pois sabe-se que a ansiedade até certo nível, pode favorecer o desempenho cognitivo. / Knowing that the muscarinic cholinergic system modulates cognitive functions, we propose to study the muscarinic toxins isolated from the venom of M. lemniscatus, MT-Mlα and MT-Mlβ, on the process of learning and memory. Male Wistar rats were injected by intrahippocampal pathway with MT-Mlα, MT-Mlβ or Ringer\'s solution (SRG). After a period of seven days training in Morris Water Maze (MWM), rats received a toxin or SRG (Inoculation day) and 20 min and 24 h after inoculation were tested in LAM. The MT-Mlα reduced the time spent in the quadrant of the previous day, indicating interference in the evocation of memory. On the other hand, the MT-Mlβ caused a facilitatory effect in recovering the location of the plataform. Anxiety was assessed in the Elevated Plus Maze, the training was done at 30 min after injection and 24 h after the test. Treatment with MT-Mlβ shown to have an anxiogenic effect, which may have contributed to the facilitatory effect on memory, since it is known that anxiety to a certain level can help cognitive performance.

Eventuais alterações no substrato anatômico miocárdico, no sistema nervoso autônomo (SNA) cardíaco intrínseco, envolvendo os plexos ganglionares (PG) comumente presentes em organizações de gordura epicárdicas denominadas fatpads (FP) ou a expressão dos receptores muscarínicos, poderiam ser responsáveis pela gênese e manutenção da fibrilação atrial (FA). Com o objetivo de analisar a relação entre fibrilação atrial permanente (FAP) e possíveis alterações anatômicas e micromorfológicas do coração, do SNA cardíaco intrínseco e da expressão dos receptores muscarínicos miocárdicos, foram estudados 13 corações de autópsias de portadores de FAP e cardiopatia crônica definida (grupo I) e 13 casos pareados pela mesma doença cardíaca, porém sem esta arritmia (grupo II). Foram analisados a anatomia da drenagem venosa do átrio esquerdo (AE), peso do coração, espessura do septo ventricular e diâmetro dos FP epicárdicos. Foram ressecadas duas amostras no átrio direito (AD1 e AD2), três no átrio esquerdo - no trajeto médio da VoAe (AE1), na junção da veia pulmonar superior esquerda (AE2) e na aurícula (AE3), três em FPs, atrial esquerdo superior (FP1), atrial direito posterior (FP 2) e no atrial esquerdo póstero-medial (FP 3) e uma amostra do septo ventricular (SIV), como controle. As alterações estruturais das fibras miocárdicas, as espessuras do epicárdio, endocárdio e miocárdio e o percentual de colágeno intersticial no miocárdio foram analisados através de histomorfometria computadorizada sob coloração de tricrômio de Masson. O SNA cardíaco intrínseco foi analisado através imuno-histoquímica para S-100 e tirosina-hidroxilase quanto a: quantidade e área das fibras nervosas, quantidade e área média de fibras simpáticas, quantidade e área média de fibras parassimpáticas e proporção de fibras simpáticas/parassimpáticas. A expressão miocárdica dos receptores muscarínicos 1 a 5 (M1 a M5) foi avaliada pela proporção positiva no miocárdio nos cortes AD1, AE1, AE2 e FP1. Não houve diferenças entre os grupos quanto às variáveis anatômicas e ao percentual de colágeno intersticial. A análise do SNA revelou fibras nervosas com menor área no grupo I, redução do número de fibras nervosas totais e parassimpáticas nos cortes AD1 e SIV, aumento de fibras totais e parassimpáticas AE2 e FP2 e aumento do número de fibras simpáticas nos cortes AD2, AE1, AE2 e AE3. Quanto à expressão dos receptores muscarínicos, houve aumento significante na porcentagem positiva para M1 em todas as regiões, exceto na AE1 (média de todos os cortes, grupo I 5,84 e grupo II 2,92, p=0,002); o M2 e M3 apenas junto ao FP1 (M2 grupo I 5,67 e grupo II 3,63, p=0,037; M3 grupo I 30,95 e grupo II 20,13, p=0,026) e o M4 foi aumentado no grupo I na região AE1 (grupo I 9,90 e grupo II 4,45, p=0,023); não houve alteração estatisticamente significante no M5. A anatomia e a disposição das fibras musculares atriais, bem como a fibrose intersticial não parecem estar relacionadas à FAP nos grupos estudados. Alterações no número de fibras nervosas bem como e alterações na expressão dos receptores muscarínicos atriais, especialmente o M1, particularmente em regiões próximas aos PG, parecem estar relacionadas à FAP, indicando a importância da modulação autonômica nesta arritmia / Possible changes in myocardial substrate, in the intrinsic cardiac autonomic nervous system (ANS), involving the ganglionated plexus (GP) present in fat-pads (FP) or the expression of muscarinic receptors could be responsible for the genesis and maintenance of atrial fibrillation (AF). Aiming to analyze the relationship between permanent atrial fibrillation (pAF) and possible anatomical and micromorphological heart changes, intrinsic cardiac ANS and expression of myocardial muscarinic receptors, 13 hearts from autopsies of patients with PAF and chronic heart disease (group I) were studied; and 13 cases matched by the same heart disease, but without this arrhythmia (group II). It was analyzed the anatomy of the venous drainage of the left atrium (LA), heart weight, ventricular septal thickness and diameter of epicardial FP. Two samples were taken in the right atrium (RA1 and RA2), three in the left atrium - in the middle portion of the left atrium oblique vein (LaOv LA1), at the junction of left superior pulmonary vein (LA2) and in the auricle (LA3), three FPs, left atrial superior (FP 1), right atrial posterior (FP 2) and the left atrial posteromedial (FP 3) and one sample of the ventricular septum (VS), as control. The structural changes of the myocardial fibers, thickness of the epicardium, endocardium and myocardium, and the percentage of interstitial collagen in the myocardium were analyzed by computerized histomorphometry on Masson trichrome staining. The intrinsic cardiac ANS was analyzed through immunohistochemistry for S-100 and tyrosine hydroxylase regarding the: amount and area of nerve fibers, amount and average area of sympathetic fibers, number and average area of parasympathetic fibers and sympathetic/parasympathetic fiber proportion. The myocardial expression of muscarinic receptors 1-5 (M1 to M5) was evaluated by positive ratio in the myocardium in sections RA1, LA1, LA2 and FP1. There were no differences between groups regarding the anatomical variant and the percentage of interstitial collagen. Analysis of the ANS revealed nerve fibers with the smallest area in group I, reduction in the number of total and parasympathetic nerve fibers of sections RA1 and VS, increase of total and parasympathetic fibers LA2 and FP2 and increased numbers of sympathetic fibers in sections RA2, LA1, LA2 and LA3. Regarding the expression of muscarinic receptors, there was a significantly increase in the positive percentage for M1 in all regions except for LA1 (average of all the sections, group I 5.84 and group II 2.92, p = 0.002), M2 and M3 just adjacent to the FP1 (M2 Group I 5.67 and Group II 3.63, p = 0.037; M3 Group I 30.95 and Group II 20.13, p = 0.026) and the M4 was increased in group I in the region LA1 (group I 9.90 and group II 4.45, p = 0.023) and there was no statistically significant change in the M5. The anatomy and arrangement of atrial muscle fibers, as well as the interstitial fibrosis did not appear to be related to PAF in both studied groups. Changes in the number of nerve fibers as well as changes in expression of atrial muscarinic receptors, specially the M1, particularly in regions close to the GP appear to be related to pAF, indicating the importance of autonomic modulation in this arrhythmia

(in English): The aim of the work was to perform in-depth analysis of M2KO mice both at baseline and upon a challenge with a cold stress and to explore the role of opposing receptors (i.e. adrenoceptors) in adaptation to lacking M2-receptors in the heart. We have performed receptor binding studies, study of receptor gene expression, echocardiography, telemetric monitoring of heart rate, body temperature and activity, heart rate variability and biorhythm analysis, analysis of heart rate response to the application of drugs (carbachol, atropine, isoprenaline, propranolol), assessment of adenylyl cyclase and NO synthase activity, measurement of catecholamine blood concentration and gene expression of catecholamine-synthesizing enzymes. We have found that the disruption of M2-receptor gene caused a compensatory decrease of cardiostimulatory β1-adrenoceptors and β2-adrenoceptors with corresponding down-regulation of the gene expression, M3-receptors were down-regulated as well. Missing M2-receptors were functionally replaced by the main cardioinhibitory β3-adrenoceptors that were up-regulated, not by cardioinhibitory M4-receptors. β3-adrenoceptors were found to signal through adenylyl cyclase instead of NO synthase. All these changes were found in the left ventricle only, so heterologous regulation is...

Cholinergic enzymes and muscarinic receptors in nuclei of rat medulla oblongata were examined after unilateral vagotomy to determine their association with efferent vagal neurons. Vagotomy caused an ipsilateral depletion of acetylcholinesterase from the dorsal motor nucleus of the vagus (DNV) and the nucleus ambiguus (NA). Choline acetyltransferase activity was reduced in ipsilateral DNV, nucleus tractus solitarius and rostral NA. Muscarinic receptor localization by autoradiography with [3H]quinuclidinyl benzilate (QNB) revealed marked intranuclear variations in receptor density. Vagotomy had no effect on the QNB binding pattern. Loss of cholinergic enzymes is a consistent response of motor and preganglionic autonomic neurons to axotomy. Depletion of muscarinic receptors is an additional component of axon reaction in brain stem motoneurons. Accordingly, previous studies have shown a decrease in neurotransmitter-related proteins after axotomy of motoneurons. In the present study, cholinergic enzymes were depleted from axotomized vagal neurons but receptors were not. It is concluded that muscarinic receptors in the DNV and NA are not associated with vagal efferent neurons.

The intrinsic cardiac plexus represents a major peripheral integration site for neuronal, hormonal, and locally produced neuromodulators controlling efferent neuronal output to the heart. This study examined the interdependence of norepinephrine, muscarinic agonists, and ANG II, to modulate intrinsic cardiac neuronal activity. Intracellular voltage recordings from whole-mount preparations of the guinea pig cardiac plexus were used to determine changes in active and passive electrical properties of individual intrinsic cardiac neurons. Application of either adrenergic or muscarinic agonists induced changes in neuronal resting membrane potentials, decreased afterhyperpolarization duration of single action potentials, and increased neuronal excitability. Adrenergic responses were inhibited by removal of extracellular calcium ions, while muscarinic responses were inhibited by application of TEA. The adrenergic responses were heterogeneous, responding to a variety of receptor-specific agonists (phenylephrine, clonidine, dobutamine, and terbutaline), although α-receptor agonists produced the most frequent responses. Application of ANG II alone produced a significant increase in excitability, while application of ANG II in combination with either adrenergic or muscarinic agonists produced a much larger potentiation of excitability. The ANG IIinduced modulation of firing was blocked by the angiotensin type 2 (AT 2) receptor inhibitor PD 123319 and was mimicked by the AT 2 receptor agonist CGP-42112A. AT 1 receptor blockade with telmasartin did not alter neuronal responses to ANG II. These data demonstrate that ANG II potentiates both muscarinically and adrenergically mediated activation of intrinsic cardiac neurons, doing so primarily via AT 2 receptor-dependent mechanisms. These neurohumoral interactions may be fundamental to regulation of neuronal excitability within the intrinsic cardiac nervous system.

The lateral prefrontal cortex (LPFC) and the anterior cingulate cortex (ACC) are two key regions of the frontal executive control network. Ascending cholinergic pathways differentially innervate these two functionally distinct cortices to modulate arousal and motivational signaling for higher-order functions. The action of acetylcholine (ACh) in sensory cortices is constrained by layer, anatomical cell type, and subcellular localization of distinct receptors, but little is known about the nature and organization of frontal-cholinergic circuitry in primates. In this dissertation, we characterized the anatomical localization of muscarinic acetylcholine receptors (mAChRs), m1 and m2–the predominant subtypes in the cortex–and their expression profiles on distinct cell types and pathways in ACC and LPFC of the rhesus monkey, using immunohistochemistry, anatomical tract-tracing, whole cell patch-clamp recordings, and single nucleus RNA sequencing. In the first series of studies (Chapter 2), we used immunohistochemistry and high-resolution confocal microscopy to reveal regional differences in m1 and m2 receptor localization on excitatory pyramidal and inhibitory neuron subpopulations and subcellular compartments in ACC (A24) versus LPFC (A46) of adult rhesus monkeys (Macaca mulatta; aged 7-11 yrs; 4 males and 2 females). The ACC exhibited a greater proportion of m2+ inhibitory neurons and a greater density of presynaptic m2+ receptors localized on inhibitory (VGAT+) terminations on pyramidal neurons compared to the LPFC. This result suggests a greater cholinergic suppression of GABAergic neurotransmission in ACC. In a second set of experiments (Chapter 3), we examined the heterogeneity of m1 and m2 laminar expression in functionally distinct ACC areas A24, A25, and A32. These differ in their connections with higher order cortical areas and limbic structures, such as the amygdala (AMY). The density of m1+ and/or m2 expressing (m1+/m2+) pyramidal neurons was significantly greater in A24 compared to A25 and to A32, while A25 exhibited a significantly greater density of m2+VGAT+ terminals. In addition, we examined the substrates for cholinergic modulation of long-range cortico-limbic processing using bidirectional neural tracers to label one specific subtype, the AMY-targeting projection neurons in these ACC areas. Compared to A24 and A32, the limbic ventral A25 had a greater density of m1+/m2+ AMY-targeting pyramidal neurons across upper layers 2-3 and deep layers 5-6, suggesting stronger cholinergic modulation of amygdalar outputs. Lastly (Chapter 4), we assessed the functional effects of cholinergic modulation on excitatory and inhibitory synaptic activity as well as the molecular signatures related to m1 and m2 receptor expression. In experiments using in vitro whole-cell patch-clamp recordings of layer 3 pyramidal neurons in ACC and LPFC, we found that application of the cholinergic agonist carbachol (CCh) significantly decreased the frequency of excitatory postsynaptic currents (EPSCs) to a greater extent in ACC A24 than in LPFC A46. Using single nucleus RNA sequencing, we found that enriched m1 and m2 transcriptional profiles in distinct cell-types and frontal areas (ACC A24 and LPFC A46) had differentially expressed genes associated with down-stream signaling cascades related to synaptic signaling and plasticity. Together, these data reveal the anatomical, functional, and transcriptomic neural substrates of diverse cholinergic modulation of local excitatory and inhibitory circuits and long-range cortico-limbic pathways in functionally-distinct ACC and LPFC frontal areas that are important for cognitive-emotional integration.

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