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ROLE OF THE ADRENERGIC PATHWAYS OF THE LATERAL HYPOTHALAMUS ON WATER-INTAKE AND PRESSER RESPONSE INDUCED BY THE CHOLINERGIC ACTIVATION OF THE MEDIAL SEPTAL AREA IN RATS

Callera, J. C.; Saad, W. A.; Camargo, LAD; Renzi, A.; Deluca, L. A.; Menani, Jose Vanderlei
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 153-155
ENG
Relevância na Pesquisa
46.25%
In the present experiments, we investigated a possible involvement of noradrenergic receptors of the lateral hypothalamus (LH) in the water intake and presser response induced by cholinergic stimulation of the medial septal area (MSA) in rats. The cholinergic agonist carbachol (2 nmol) injected into the MSA induced water intake and presser response. The injection of an alpha(2)-adrenergic agonist, clonidine (20 and 40 nmol), but not of an alpha(1)-adrenergic agonist, phenylephrine (80 and 160 nmol), into the LH inhibits the water intake induced by carbachol injected into the MSA. The injection of clonidine or phenylephrine into the LH produced no change in the MAP increase induced by carbachol injected into the MSA. The present results suggest that adrenergic pathways involving the LH are important for the water intake: but not for the presser response, induced by cholinergic activation of the MSA.

EFFECT OF CHOLINERGIC STIMULATION OF THE AMYGDALOID COMPLEX ON WATER AND SALT INTAKE

Saad, W. A.; Bengtson, R. M.; Menani, Jose Vanderlei; Camargo, LAA; Renzi, A.; Silveira, JEN
Fonte: Associação Brasileira de Divulgação Científica (ABRADIC) Publicador: Associação Brasileira de Divulgação Científica (ABRADIC)
Tipo: Artigo de Revista Científica Formato: 915-920
ENG
Relevância na Pesquisa
56.27%
The effect of carbachol (80 nmol/mul) injection into the amygdaloid nuclear complex (AMG) on sodium appetite and water intake was studied in male Holtzman rats weighing 240-270 g. Twenty-five satiated rats and 38 water-deprived rats were used in the experiment on water intake. In the experiment on sodium intake, 19 rats were injected with atropine + carbachol and 9 rats with hexamethonium + carbachol. After carbachol injection into the AMG, water intake decreased in rats submitted to 30 h of water deprivation (10.28 +/- 1.04 ml/120 min vs 0.69 +/- 0.22 ml/120 min). The decrease in water intake was blocked by prior local injection of a tropine (20 nmol/1 mul)(11.66 +/- 1.46 ml/120 min vs 0.69 +/- 0.22 ml/120 min), but not of hexamethonium (30 nmol/1 mul), into the AMG. In water-deprived animals, carbachol injection into the AMG caused a decrease in sodium chloride intake (6.16 +/- 1.82 ml/h vs 0.88 +/- 0.54 ml/h) which was blocked by previous injection of hexamethonium but not of a tropine. These results suggest that the cholinergic system of the AMG plays a role in the control of water and salt intake.

Cholinergic stimulation with pyridostigmine reduces the QTc interval in coronary artery disease

Castro,R.R.T.; Porphirio,G.; Serra,S.M.; Nóbrega,A.C.L.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2002 EN
Relevância na Pesquisa
46.44%
Parasympathetic dysfunction is an independent risk factor in patients with coronary artery disease; thus, cholinergic stimulation is a potential therapeutic measure that may be protective by acting on ventricular repolarization. The purpose of the present study was to determine the effects of pyridostigmine bromide (PYR), a reversible anticholinesterase agent, on the electrocardiographic variables, particularly QTc interval, in patients with stable coronary artery disease. In a randomized double-blind crossover placebo-controlled study, simultaneous 12-lead electrocardiographic tracings were obtained at rest from 10 patients with exercise-induced myocardial ischemia before and 2 h after the oral administration of 45 mg PYR or placebo. PYR increased the RR intervals (pre: 921 ± 27 ms vs post: 1127 ± 37 ms; P<0.01) and, in contrast with placebo, decreased the QTc interval (pre: 401 ± 3 ms vs post: 382 ± 3 ms; P<0.01). No other electrocardiographic variables were modified (PR segment, QT interval, QT and QTc dispersions). Cholinergic stimulation with PYR caused bradycardia and reduced the QTc interval without important side effects in patients with coronary disease. These effects, if confirmed in studies over longer periods of administration...

Extracellular calcium and cholinergic stimulation of isolated canine parietal cells.

Soll, A H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1981 EN
Relevância na Pesquisa
46.53%
The role of calcium gating in cholinergic stimulation of the function of parietal cells was studied using cells isolated from canine fundic mucosa by treatment with collagenase and EDTA and enriched by velocity separation in an elutriator rotor. Monitoring the accumulation of [14C[ aminopyrine as an index of parietal cell response, stimulation by carbachol, but not by histamine, was highly dependent upon the concentration of extracellular calcium. Incubation of parietal cells in 0-.1 mM calcium, rather than the usual 1.8 mM concentration, reduced the response to 100 microM carbachol by 92 +/- 2%, whereas histamine stimulation was impaired by 28 +/- 5%. A similar reduction in extracellular calcium suppressed the response to gastrin (100 nM) by 67 +/- 7%. The impairment of cholinergic stimulation found at low extracellular calcium concentrations was rapidly reversed with the readdition of calcium. Lanthanum, which blocks calcium movement across membranes, caused a similar pattern of effects on secretagogue stimulation of aminopyrine accumulation, with 100 microM lanthanum suppressing carbachol stimulation by 83 +/- 2%. This concentration of lanthanum suppressed gastrin stimulation by 40 +/- 7% and histamine stimulation by only 12 +/- 9%. Carbachol...

Cholinergic Stimulation of Norepinephrine Release in Man: EVIDENCE OF A SYMPATHETIC POSTGANGLIONIC AXONAL LESION IN DIABETIC ADRENERGIC NEUROPATHY

Leveston, Steven A.; Shah, Suresh D.; Cryer, Philip E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1979 EN
Relevância na Pesquisa
46.48%
Amplification of endogenous cholinergic activity—produced by the intravenous injection of edrophonium, an acetylcholinesterase inhibitor which does not enter the central nervous system, into normal subjects—resulted in significant and briefly sustained increments in the plasma concentrations of norepinephrine (153±15−234±29 pg/ml, P < 0.01) and epinephrine (16±3−34±5 pg/ml, P < 0.01) measured with a single-isotope derivative method. These increments were not attributable to reflex responses to hemodynamic changes and similar increments in plasma norepinephrine occurred in adrenalectomized (epinephrine deficient) patients. Thus, cholinergic activation results in direct stimulation of sympathetic postganglionic neurons, with augmented norepinephrine release, and of the adrenal medullae, with augmented epinephrine release, in man. Four diabetic patients with hypoadrenergic postural hypotension exhibited blunted sympathetic postganglionic neural responses, and normal adrenomedullary responses, to cholinergic stimulation (and to standing) indicative of the presence of a sympathetic postganglionic axonal lesion in diabetic adrenergic neuropathy. Nondiabetic patients with hypoadrenergic postural hypotension due to documented or probable central nervous system lesions exhibited normal responses to cholinergic stimulation produced in this fashion demonstrating the presence of intact sympathetic postganglionic neurons and adrenal medullae in these patients and providing further support for the conceptual soundness of this approach to the study of human adrenergic physiology and pathophysiology.

Central cholinergic stimulation causes adrenal epinephrine release.

Kennedy, B; Janowsky, D S; Risch, S C; Ziegler, M G
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1984 EN
Relevância na Pesquisa
46.44%
Cholinergic drugs administered into the cerebral ventricles of animals selectively stimulate the adrenal medulla. However, the effects of central cholinergic stimulation on the sympathoadrenal system have not been studied in man. We stimulated central cholinergic activity in man by administering the cholinesterase inhibitor physostigmine to subjects pretreated with peripheral cholinergic blocking agents. A dose of 0.022 mg/kg physostigmine dramatically increased plasma epinephrine levels and slightly increased norepinephrine levels, which is consistent with selective adrenomedullary stimulation. A smaller dose of physostigmine increased epinephrine but did not alter norepinephrine levels. Subjects had increased pulse rates and blood pressures, and felt anxious while they had high plasma epinephrine levels.

Cooling effects on nitric oxide production by rabbit ear and femoral arteries during cholinergic stimulation.

Fernández, N; Monge, L; García-Villalón, A L; García, J L; Gómez, B; Diéguez, G
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1994 EN
Relevância na Pesquisa
46.44%
1. Ear (cutaneous) and femoral (deep) arteries from rabbit were perfused at 37 degrees C and 24 degrees C (cooling) and the production of nitrite, as an index of nitric oxide production, was measured under basal conditions and cholinergic stimulation. 2. In both types of arteries under control conditions, the basal production of nitrite was similar at 24 degrees C and 37 degrees C. Compared with the control conditions, the basal production of nitrite was significantly lower in ear and femoral arteries without endothelium or treated with NG-nitro-L-arginine methyl ester (L-NAME, 10(-4) M) but it was similar in those treated with atropine (10(-6) M). 3. At 37 degrees C, methacholine (10(-7)-10(-5) M) increased the production of nitrite in ear and femoral arteries; this increase persisted during 30-60 min and was practically abolished by L-NAME (10(-4) M), atropine (10(-6) M), or removal of the endothelium. In ear arteries the total nitrite production to activation with methacholine was higher at 24 degrees C than at 37 degrees C due to this production persisted increased for a longer period (> 150 min), whereas in femoral arteries it was lower at 24 degrees C than at 37 degrees C. 4. It is suggested that: (a) the endothelium of rabbit ear and femoral arteries produce nitric oxide under basal conditions...

Influence of gender and the oestrous cycle on in vitro contractile responses of the rat urinary bladder to cholinergic stimulation

Longhurst, Penelope A; Levendusky, Mark
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/2000 EN
Relevância na Pesquisa
46.34%
Experiments were done to determine the influence of gender and the oestrous cycle on rat urinary bladder contractility in response to cholinergic stimulation.Bladder strips from female rats responded to high frequency stimulation with smaller contractile responses than did strips from males, and to low concentrations of carbachol with greater responses. The decreased responsiveness of bladder strips from female rats to electrical field stimulation can be primarily attributed to the rats in the oestrous stage of the oestrous cycle.Bladder strips from female rats in all stages of the oestrous cycle were more sensitive to carbachol than those from males, but there were no differences in sensitivity to electrical field stimulation.The contractile responses of strips from both male and female rats to carbachol were antagonized by muscarinic antagonists with the following rank order of affinity (pA2) estimates: 4-DAMP>>pirenzepine>methoctramine, suggesting that the receptor mediating contraction was the M3 subtype. There were no differences in pA2 values between bladder strips from male and female rats.The data indicate that responsiveness of bladder strips to electrical field stimulation and carbachol is altered in female rats in the oestrous stage of the oestrous cycle. Furthermore...

Male sex hormones promote vagally mediated reflex airway responsiveness to cholinergic stimulation

Card, Jeffrey W.; Voltz, James W.; Ferguson, Catherine D.; Carey, Michelle A.; DeGraff, Laura M.; Peddada, Shyamal D.; Morgan, Daniel L.; Zeldin, Darryl C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.4%
A sex disparity in airway responsiveness to cholinergic stimulation has been observed in laboratory mice in that males are considerably more responsive than females, but the basis for this difference is unclear. In this report, we demonstrate that male sex hormones promote murine airway responsiveness to cholinergic stimulation via vagus nerve-mediated reflex mechanisms. In tissue bath preparations, no sex-based differences were observed in the contractile responses of isolated tracheal and bronchial ring segments to carbachol, indicating that the mechanism(s) responsible for the in vivo sex difference is (are) absent ex vivo. Bilateral cervical vagotomy was found to abolish in vivo airway responsiveness to methacholine in male mice, whereas it did not alter the responses of females, suggesting a regulatory role for male sex hormones in promoting reflex airway constriction. To test this possibility, we next studied mice with altered circulating male sex hormone levels. Castrated male mice displayed airway responsiveness equivalent to that observed in intact females, whereas administration of exogenous testosterone to castrated males restored responsiveness, albeit not to the level observed in intact males. Administration of exogenous testosterone to intact female mice similarly enhanced responsiveness. Importantly...

Cholinergic stimulation blocks endothelial cell activation and leukocyte recruitment during inflammation

Saeed, Rubina W.; Varma, Santosh; Peng-Nemeroff, Tina; Sherry, Barbara; Balakhaneh, David; Huston, Jared; Tracey, Kevin J.; Al-Abed, Yousef; Metz, Christine N.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 04/04/2005 EN
Relevância na Pesquisa
46.53%
Endothelial cell activation plays a critical role in regulating leukocyte recruitment during inflammation and infection. Based on recent studies showing that acetylcholine and other cholinergic mediators suppress the production of proinflammatory cytokines via the α7 nicotinic acetylcholine receptor (α7 nAChR) expressed by macrophages and our observations that human microvascular endothelial cells express the α7 nAChR, we examined the effect of cholinergic stimulation on endothelial cell activation in vitro and in vivo. Using the Shwartzman reaction, we observed that nicotine (2 mg/kg) and the novel cholinergic agent CAP55 (12 mg/kg) inhibit endothelial cell adhesion molecule expression. Using endothelial cell cultures, we observed the direct inhibitory effects of acetylcholine and cholinergic agents on tumor necrosis factor (TNF)-induced endothelial cell activation. Mecamylamine, an nAChR antagonist, reversed the inhibition of endothelial cell activation by both cholinergic agonists, confirming the antiinflammatory role of the nAChR cholinergic pathway. In vitro mechanistic studies revealed that nicotine blocked TNF-induced nuclear factor–κB nuclear entry in an inhibitor κB (IκB)α- and IκBɛ-dependent manner. Finally, with the carrageenan air pouch model...

Cholinergic stimulation enhances cytosolic calcium ion accumulation in mouse hippocampal CA1 pyramidal neurones during short action potential trains

Beier, Steven M; Barish, Michael E
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em 01/07/2000 EN
Relevância na Pesquisa
46.34%
Acetylcholine is a regulatory cofactor for numerous activity-dependent processes of central nervous system development and plasticity in which increases in cytosolic calcium ion concentration ([Ca2+]cyto) couple membrane excitation to cellular changes. We examined how cholinergic receptor activation affects temporal and spatial aspects of increases in [Ca2+]cyto during short trains of action potentials in hippocampal CA1 pyramidal neurones. Membrane-impermeant Ca2+-sensitive dye was introduced into the cytosol during whole-cell recordings, and Ca2+-dependent fluorescence was recorded from somatic, nuclear and proximal dendrite regions with high temporal resolution.In all neuronal compartments, the cholinergic agonist carbachol (5 μM) increased resting [Ca2+]cyto and the maximum [Ca2+]cyto attained during a short action potential train. Carbachol also slowed the recovery of [Ca2+]cyto towards resting levels. The largest increases in peak cytosolic Ca2+ concentration (Δ[Ca2+]cyto) were seen in the dendrite and apical cell body, while relaxations of the carbachol-induced increase in Δ[Ca2+]cyto showed greater prolongation in the nucleus and basal cell body.Most significantly, the difference between Ca2+ signals recorded before and during exposure to carbachol consistently showed a monotonic rise and smooth fall in all cell compartments...

Shotgun proteomics implicates extracellular matrix proteins and protease systems in neuronal development induced by astrocyte cholinergic stimulation

Moore, Nadia H.; Costa, Lucio G.; Shaffer, Scott A; Goodlett, David R.; Guizzetti, Marina
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.34%
Astrocytes play an important role in neuronal development through the release of soluble factors that affect neuronal maturation. Shotgun proteomics followed by Gene Ontology analysis was used in this study to identify proteins present in the conditioned medium of primary rat astrocytes. 133 secreted proteins were identified, the majority of which were never before reported to be produced by astrocytes. Extracellular proteins were classified based on their biological and molecular functions; most of the identified proteins were involved in neuronal development. Semi-quantitative proteomic analysis was carried out to identify changes in the levels of proteins released by astrocytes after stimulation with the cholinergic agonist carbachol, as we have previously reported that carbachol-treated astrocytes elicit neuritogenesis in hippocampal neurons through the release of soluble factors. Carbachol up-regulated the secretion of 15 proteins and down-regulated the release of 17 proteins. Changes in the levels of four proteins involved in neuronal differentiation (thrombospondin-1, fibronectin, plasminogen activator inhibitor-1, and plasminogen activator urokinase) were verified by Western blot or ELISA. In conclusion, this study identified a large number of proteins involved in neuronal development in the astrocyte secretome and implicated extracellular matrix proteins and protease systems in neuronal development induced by astrocyte cholinergic stimulation.

Cholinergic stimulation of the immune system protects against lethal infection by Salmonella enterica serovar Typhimurium

Fernandez-Cabezudo, Maria J; Lorke, Dietrich E; Azimullah, Sheikh; Mechkarska, Milena; Hasan, Mohammed Y; Petroianu, Georg A; al-Ramadi, Basel K
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em /07/2010 EN
Relevância na Pesquisa
46.27%
The cholinergic nervous system has been demonstrated to attenuate the inflammatory response during sepsis via the inhibitory action of acetylcholine (ACh) on macrophages. These findings were largely based on experimental sepsis models using endotoxin as the inducing agent. Herein, however, we report that the specific inhibition of acetylcholinesterase (AChE) renders animals more resistant to infection by a virulent strain of Salmonella enterica serovar Typhimurium, a Gram-negative enteric pathogen. Inhibition of AChE was induced by a subchronic exposure to paraoxon, a potent anti-cholinesterase metabolite of the organophosphorous compound parathion. Our findings indicate that inhibition of AChE enhanced survival of infected mice in a dose-dependent fashion and this correlated with efficient control of bacterial proliferation in target organs. Immunologically, inhibition of AChE enabled the animals to mount a more effective inflammatory anti-microbial response, and to secrete higher levels of interleukin-12, a key T helper type 1-promoting cytokine. The ACh-induced enhancement in resistance to infection was abrogated by co-administration of an oxime which can reactivate AChE. Hence, in a model of Gram-negative bacterial infection, cholinergic stimulation is shown to enhance the anti-microbial immune response leading to effective control of bacterial proliferation and enhanced animal survival.

Cholinergic enhancement of perceptual learning : behavioral, physiological, and neuro-pharmacological study in the rat primary visual cortex

Kang, Jun-Il
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
EN
Relevância na Pesquisa
46.78%
Les cortices sensoriels sont des régions cérébrales essentielles pour la perception. En particulier, le cortex visuel traite l’information visuelle en provenance de la rétine qui transite par le thalamus. Les neurones sont les unités fonctionnelles qui transforment l'information sensorielle en signaux électriques, la transfèrent vers le cortex et l'intègrent. Les neurones du cortex visuel sont spécialisés et analysent différents aspects des stimuli visuels. La force des connections entre les neurones peut être modulée par la persistance de l'activité pré-synaptique et induit une augmentation ou une diminution du signal post-synaptique à long terme. Ces modifications de la connectivité synaptique peuvent induire la réorganisation de la carte corticale, c’est à dire la représentation de ce stimulus et la puissance de son traitement cortical. Cette réorganisation est connue sous le nom de plasticité corticale. Elle est particulièrement active durant la période de développement, mais elle s’observe aussi chez l’adulte, par exemple durant l’apprentissage. Le neurotransmetteur acétylcholine (ACh) est impliqué dans de nombreuses fonctions cognitives telles que l’apprentissage ou l’attention et il est important pour la plasticité corticale. En particulier...

Exocytosis in secretory cells of rat lacrimal gland. Peroxidase release from lobules and isolated cells upon cholinergic stimulation

Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 01/09/1976 EN
Relevância na Pesquisa
46.56%
Release of peroxidase from secretory cells of rat lacrimal gland upon cholinergic stimulation was studied in vitro with single lobules and isolated cells (lacrimocytes). Isolated lobules, kept in Eagle's medium, remain structurally intact and reaction product of peroxidase is confined to cisternae of rough endoplasmic reticulum, elements of the Golgi apparatus, and all secretory granules. Morphologically, exocytosis occurs by membrane fusion and discharge of granule content. The highest rate of peroxidase released from lobules is observed at 10(- 4) M carbamylcholine. The specific activity of peroxidase released into the medium is fourfold higher as compared to the lobules. Release of peroxidase is suppressed by atropine when added before or after the addition of carbamylcholine. At 4 degrees C, no peroxidase release occurs upon cholinergic stimulation. The exocytotic release of peroxidase is dependent on energy supply, as indicated by substantial inhibition (at 37 degrees C) under anoxic conditions or in the presence of dinitrophenol, KCN, or carboxyatractyloside. Furthermore, the process is sensitive to colchicine and vinblastine. Isolated lacrimocytes, consiting of 95% secretory acinar cells, are prepared by digestion with collagenase...

Pharmacological Mechanisms of Cortical Enhancement Induced by the Repetitive Pairing of Visual/Cholinergic Stimulation

Kang, Jun-Il; Huppé-Gourgues, Frédéric; Vaucher, Elvire
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 29/10/2015 EN
Relevância na Pesquisa
46.34%
Repetitive visual training paired with electrical activation of cholinergic projections to the primary visual cortex (V1) induces long-term enhancement of cortical processing in response to the visual training stimulus. To better determine the receptor subtypes mediating this effect the selective pharmacological blockade of V1 nicotinic (nAChR), M1 and M2 muscarinic (mAChR) or GABAergic A (GABAAR) receptors was performed during the training session and visual evoked potentials (VEPs) were recorded before and after training. The training session consisted of the exposure of awake, adult rats to an orientation-specific 0.12 CPD grating paired with an electrical stimulation of the basal forebrain for a duration of 1 week for 10 minutes per day. Pharmacological agents were infused intracortically during this period. The post-training VEP amplitude was significantly increased compared to the pre-training values for the trained spatial frequency and to adjacent spatial frequencies up to 0.3 CPD, suggesting a long-term increase of V1 sensitivity. This increase was totally blocked by the nAChR antagonist as well as by an M2 mAChR subtype and GABAAR antagonist. Moreover, administration of the M2 mAChR antagonist also significantly decreased the amplitude of the control VEPs...

Cholinergic Stimulation Enhances Bayesian Belief Updating in the Deployment of Spatial Attention

Vossel, Simone; Bauer, Markus; Mathys, Christoph; Adams, Rick A.; Dolan, Raymond J.; Stephan, Klaas E.; Friston, Karl J.
Fonte: Society for Neuroscience Publicador: Society for Neuroscience
Tipo: Artigo de Revista Científica
Publicado em 19/11/2014 EN
Relevância na Pesquisa
46.38%
The exact mechanisms whereby the cholinergic neurotransmitter system contributes to attentional processing remain poorly understood. Here, we applied computational modeling to psychophysical data (obtained from a spatial attention task) under a psychopharmacological challenge with the cholinesterase inhibitor galantamine (Reminyl). This allowed us to characterize the cholinergic modulation of selective attention formally, in terms of hierarchical Bayesian inference. In a placebo-controlled, within-subject, crossover design, 16 healthy human subjects performed a modified version of Posner's location-cueing task in which the proportion of validly and invalidly cued targets (percentage of cue validity, % CV) changed over time. Saccadic response speeds were used to estimate the parameters of a hierarchical Bayesian model to test whether cholinergic stimulation affected the trial-wise updating of probabilistic beliefs that underlie the allocation of attention or whether galantamine changed the mapping from those beliefs to subsequent eye movements. Behaviorally, galantamine led to a greater influence of probabilistic context (% CV) on response speed than placebo. Crucially, computational modeling suggested this effect was due to an increase in the rate of belief updating about cue validity (as opposed to the increased sensitivity of behavioral responses to those beliefs). We discuss these findings with respect to cholinergic effects on hierarchical cortical processing and in relation to the encoding of expected uncertainty or precision.

Role of the adrenergic pathways of the lateral hypothalamus on water intake and pressor response induced by the cholinergic activation of the medial septal area in rats

Callera, João Carlos; Saad, Wilson Abrão; Camargo, Luiz Antonio de Arruda; Renzi, Antonio; Luca Junior, Laurival Antonio de; Menani, José Vanderlei
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 153-155
ENG
Relevância na Pesquisa
46.28%
In the present experiments, we investigated a possible involvement of noradrenergic receptors of the lateral hypothalamus (LH) in the water intake and pressor response induced by cholinergic stimulation of the medial septal area (MSA) in rats. The cholinergic agonist carbachol (2 nmol) injected into the MSA induced water intake and pressor response. The injection of an α2-adrenergic agonist, clonidine (20 and 40 nmol), but not of an α1-adrenergic agonist, phenylephrine (80 and 160 nmol), into the LH inhibits the water intake induced by carbachol injected into the MSA. The injection of clonidine or phenylephrine into the LH produced no change in the MAP increase induced by carbachol injected into the MSA. The present results suggest that adrenergic pathways involving the LH are important for the water intake, but not for the pressor response, induced by cholinergic activation of the MSA. © 1994.

Nuclear calcium signaling evoked by cholinergic stimulation in hippocampal CA1 pyramidal neurons

Power, John; Sah, Pankaj
Fonte: Society for Neuroscience Publicador: Society for Neuroscience
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.53%
The cholinergic system is thought to play an important role in hippocampal-dependent learning and memory. However, the mechanism of action of the cholinergic system in these actions in not well understood. Here we examined the effect of muscarinic receptor stimulation in hippocampal CA1 pyramidal neurons using whole-cell recordings in acute brain slices coupled with high-speed imaging of intracellular calcium. Activation of muscarinic acetylcholine receptors by synaptic stimulation of cholinergic afferents or application of muscarinic agonist in CA1 pyramidal neurons evoked a focal rise in free calcium in the apical dendrite that propagated as a wave into the soma and invaded the nucleus. The calcium rise to a single action potential was reduced during muscarinic stimulation. Conversely, the calcium rise during trains of action potentials was enhanced during muscarinic stimulation. The enhancement of free intracellular calcium was most pronounced in the soma and nuclear regions. In many cases, the calcium rise was distinguished by a clear inflection in the rising phase of the calcium transient, indicative of a regenerative response. Both calcium waves and the amplification of action potential-induced calcium transients were blocked the emptying of intracellular calcium stores or by antagonism of inositol 1...

Role of the medial septal area on the cardiovascular, fluid and electrolytic responses to angiotensin II and cholinergic activation into the subfornical organ in rats

Colombari, D. S. de Almeida; Haibara, A. S.; Camargo, L. A. de Arruda; Saad, W. A.; Renzi, Antonio; Deluca, L. A.; Menani, José Vanderlei
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 249-254
ENG
Relevância na Pesquisa
46.31%
In the present study we investigated the effect of electrolytic lesion of the medial septal area (MSA) on the pressor and dipsogenic response to cholinergic activation and angiotensin II (ANGII) injection into the subfornical organ (SFO) in rats. In addition the effect of MSA lesion on the natriuresis, kaliuresis and diuresis after cholinergic activation of the SFO was also investigated. Sham- and MSA-lesioned rats with a stainless steel cannula implanted into the SFO was used. The injection of ANGII (12 ng) into the SFO in sham rats produced pressor (24 ± 2 mmHg) and dipsogenic (9.6 ± 1.1 ml/h) responses. MSA lesion, both acute (2-6 days) and chronic (15-19 days), reduced the pressor (14 ± 2 mmHg) and dipsogenic (2.7 ± 1 ml/h) responses to ANGII into SFO. The injection of the cholinergic agonist carbachol (2 nmol) into the SFO in sham rats produced pressor (48 ± 4 mmHg), dipsogenic (10 ± 1.2 ml/h), natriuretic (457 ± 58 μEq/2 h) and kaliuretic (249 ± 16 μEq/2 h) responses. Acute, but not chronic MSA lesion reduced the pressor (27 ± 3 mmHg), natriuretic (198 ± 55 μEq/2 h) and kaliuretic (128 ± 16 μEq/2 h) responses to carbachol into SFO. No change in the dipsogenic response to carbachol into the SFO was observed in MSA-lesioned rats. Antidiuresis after carbachol was observed only in MSA-lesioned rats. The present results show that the MSA plays a role on the pressor...