Publications by authors named "Keele N"

Students are required to complete supervised practice hours prior to becoming Registered Dietitians and Physician Assistants. Research suggests that environmental and social factors affect dietetic interns' diets during their internship, although these factors have not been studied among physician assistant interns. This cross-sectional study utilized an online survey to compare dietetic interns' ( = 81) and physician assistant interns' ( = 79) fruit and vegetable intake, food security, barriers to healthy eating, and empowerment for making healthy dietary choices during an internship.

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The purpose of this study was to develop an in situ model for dark cutting beef. Iodoacetic acid (IAA) was injected at different concentrations (0, 0.625, 1.

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Females are more likely to develop post-traumatic stress disorder (PTSD) than males. Also, symptoms of PTSD frequently precede alcohol abuse in females. Stressful, threat-related stimuli are evaluated by the amygdala, which is critical for establishing the emotional salience of environmental stimuli.

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Hyperactivation of the amygdala is implicated in anxiety and mood disorders, but the precise underlying mechanisms are unclear. We previously reported that depletion of serotonin (5-hydroxytryptamine, 5-HT) in the basolateral nucleus of the amygdala (BLA) using the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) potentiated learned fear and increased glutamate receptor (Glu) expression in BLA. Here we investigated the hypothesis that CaMKII facilitates anxiety-like behavior and increased Glu/AMPA receptor subunit A1 (GluA1) expression following depletion of 5-HT in the BLA.

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Our previous experiments demonstrated that systemic depletion of serotonin (5-hydroxytryptamine, 5-HT), similar to levels reported in patients with emotional disorders, enhanced glutamateric activity in the lateral nucleus of the amygdala (LA) and potentiated fear behaviors. However, the effects of isolated depletion of 5-HT in the LA, and the molecular mechanisms underlying enhanced glutamatergic activity are unknown. In the present study, we tested the hypothesis that depletion of 5-HT in the LA induces increased fear behavior, and concomitantly enhances glutamate receptor (GluR) expression.

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Deficits in serotonin (5-hydroxytryptamine, 5-HT) neurotransmission are implicated in abnormal emotional behaviors such as aggression, anxiety, and depression. However, the specific 5-HT receptor mechanisms involved are not well understood. The role of 5-HT receptors in fear potentiated startle, (FPS) was examined in rats chronically treated with -chlorophenylalanine (PCPA) to reduce brain 5-HT.

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Selective serotonin reuptake inhibitors (SSRIs) represent a class of pharmaceuticals previously reported in aquatic ecosystems. SSRIs are designed to treat depression and other disorders in humans, but are recognized to elicit a variety of effects on aquatic organisms, ranging from neuroendocrine disruption to behavioral perturbations. However, an understanding of the relationships among mechanistic responses associated with SSRI targets and ecologically important behavioral responses of fish remains elusive.

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The amygdala is a key limbic structure strongly implicated in both epilepsy and anxiety disorders. Epilepsy-like mechanisms involve an increased glutamatergic activity, whereas disturbances in serotonin [5-hydroxytryptamine (5-HT)] systems are associated with anxiety-like behavior. Previous studies suggest that low 5-HT increases amygdala excitability, but the molecular mechanisms are not well characterized.

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Temporal lobe epilepsy may be associated with emotional difficulties such as depression and anxiety. Because the amygdala is involved in both epilepsy and emotion, common neural mechanisms in this temporal lobe structure may underlie the emotional disturbances observed in people with epilepsy. The neurotransmitter serotonin (5-hydroxytryptamine, or 5-HT) is implicated in many psychopathologies, and 5-HT also modulates amygdala excitability.

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Neuronal hyperexcitability in limbic areas, especially the amygdala, is a significant underlying mechanism associated with complex partial seizures (CPS). CPS may be comorbid with emotional disturbances, especially major mood disorders, anxiety, and aggression. Anticonvulsant medications such as phenytoin are also mood-stabilizing, and have been used for treatment of behavioral dyscontrol in impulsive aggressive individuals.

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Phenytoin is a widely used anticonvulsant drug that also reduces aggressive behavior. Aggression in humans and animals is often associated with low serotonin levels. This study examined the anti-aggressive properties of phenytoin in rodent isolation-induced aggression using a resident-intruder test to quantify aggression.

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Autoantibodies to alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors may contribute to chronic hyperexcitability syndromes and neurodegeneration, but their origin is unclear. We examined LP-BM5 murine leukemia virus-infected mice, which manifest excitotoxic brain lesions and hypergammaglobulinemia, for the presence of AMPA-receptor Ab's. Endogenous IgG accumulated upon neurons in the neocortex and caudate/putamen of infected mice and interacted with native and recombinant AMPA-receptor subunits with the following relative abundance: GluR3 > or = GluR1 > GluR2 = GluR4, as determined by immunoprecipitation.

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Postsynaptic metabotropic glutamate (mGlu) receptor-activated inward current mediated by Na(+)-Ca(2+) exchange was compared in basolateral amygdala (BLA) neurons from brain slices of control (naïve and sham-operated) and amygdala-kindled rats. In control neurons, the mGlu agonist, quisqualate (QUIS; 1-100 microM), evoked an inward current not associated with a significant change in membrane slope conductance, measured from current-voltage relationships between -110 and -60 mV, consistent with activation of the Na(+)-Ca(2+) exchanger. Application of the group I selective mGlu receptor agonist (S)-3,5-dihydroxyphenylglycine [(S)-DHPG; 10-1000 microM] or the endogenous agonist, glutamate (10-1000 microM), elicited the exchange current.

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Differential effects of metabotropic glutamate receptor antagonists on bursting activity in the amygdala. Metabotropic glutamate receptors (mGluRs) are implicated in both the activation and inhibition of epileptiform bursting activity in seizure models. We examined the role of mGluR agonists and antagonists on bursting in vitro with whole cell recordings from neurons in the basolateral amygdala (BLA) of amygdala-kindled rats.

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Long-lasting modifications of synaptic transmission can be induced in the amygdala by electrical stimulation as done in the long-term potentiation (LTP) model of learning and memory and the kindling model of epilepsy. The present study reports for the first time a long-lasting potentiation (LLP) of synaptic transmission that is induced pharmacologically by the activation of group III metabotropic glutamate receptors (mGluRs) in basolateral amygdala (BLA) neurons. In whole cell voltage-clamp mode, BLA neurons were recorded in brain slices from control rats and rats with amygdala-kindled seizures.

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1. Inward currents evoked by metabotropic glutamate receptor (mGlu) agonists quisqualate and 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) were characterized in the basolateral nucleus of the amygdala. Currents were recorded with whole-cell patch electrodes in the presence of D-2-amino-5-phosphonovaleric acid (D-APV, 50 microM), 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX, 30 microM) and tetrodotoxin (TTX, 1 microM).

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Modulation of excitatory synaptic transmission by presynaptic metabotropic glutamate receptors (mGluRs) was examined in brain slices from control rats and rats with amygdala-kindled seizures. Using whole-cell voltage-clamp and current-clamp recordings, this study shows for the first time that in control and kindled basolateral amygdala neurons, two pharmacologically distinct presynaptic mGluRs mediate depression of synaptic transmission. Moreover, in kindled neurons, agonists at either group II- or group III-like mGluRs exhibit a 28- to 30-fold increase in potency and suppress synaptically evoked bursting.

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1. Metabotropic glutamate receptor (mGluR)-agonist-induced hyperpolarizations and corresponding outward currents were analyzed in basolateral amygdala (BLA) neurons in rat brain slice preparations with current-clamp and single-electrode voltage-clamp recording to characterize the mGluR subtype(s) and the ion channel(s) mediating this response. 2.

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1. Intracellular recordings were made from neurons of the basolateral amygdala (BLA) in in vitro slice preparations to determine long-term differences in metabotropic glutamate receptor (mGluR) agonist-induced membrane responses in control and amygdala-kindled rats. 2.

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Glutamatergic excitatory postsynaptic potentials (EPSPs) in the basolateral amygdala (BLA) are reduced in amplitude following agonist activation of presynaptic metabotropic glutamate receptors (mGluR). In this study, the effect of a presumed mGluR antagonist, (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG), was investigated on the EPSP recorded intracellularly in BLA neurons. Superfusion of MCPG (500 microM) significantly reduced the amplitude of evoked EPSPs.

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The metabotropic glutamate receptor (mGluR) antagonist, (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG; 500 microM), was tested on intracellularly recorded epileptiform activity induced by 4-aminopyridine (4-AP) in amygdala neurons. Superfusing 4-AP (1 mM) produced interictal spiking followed by ictal bursting. MCPG prevented the progressive transition from interictal spiking to ictal bursting but affected neither induction of interictal spiking nor maintenance of ongoing ictal bursting.

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