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Effects of nifedipine on renal and cardiovascular responses to neuropeptide y in anesthetized rats
2021
Neuropeptide Y (NPY) acts via multiple receptor subtypes termed Y1, Y2 and Y5. While Y1 receptor-mediated effects, e.g., in the vasculature, are often sensitive to inhibitors of L-type Ca2+ channels such as nifedipine, little is known about the role of such channels in Y5-mediated effects such as diuresis and natriuresis. Therefore, we explored whether nifedipine affects NPY-induced diuresis and natriuresis. After pre-treatment with nifedipine or vehicle, anesthetized rats received infusions or bolus injections of NPY. Infusion NPY (1 µg/kg/min) increased diuresis and natriuresis, and this was attenuated by intraperitoneal injection of nifedipine (3 µg/kg). Concomitant decreases in heart ra…
Cannabinoid CB1 receptors in distinct circuits of the extended amygdala determine fear responsiveness to unpredictable threat.
2016
The brain circuits underlying behavioral fear have been extensively studied over the last decades. Although the vast majority of experimental studies assess fear as a transient state of apprehension in response to a discrete threat, such phasic states of fear can shift to a sustained anxious apprehension, particularly in face of diffuse cues with unpredictable environmental contingencies. Unpredictability, in turn, is considered an important variable contributing to anxiety disorders. The networks of the extended amygdala have been suggested keys to the control of phasic and sustained states of fear, although the underlying synaptic pathways and mechanisms remain poorly understood. Here, we…
Passive exposure to speech sounds induces long-term memory representations in the auditory cortex of adult rats
2016
AbstractExperience-induced changes in the functioning of the auditory cortex are prominent in early life, especially during a critical period. Although auditory perceptual learning takes place automatically during this critical period, it is thought to require active training in later life. Previous studies demonstrated rapid changes in single-cell responses of anesthetized adult animals while exposed to sounds presented in a statistical learning paradigm. However, whether passive exposure to sounds can form long-term memory representations remains to be demonstrated. To investigate this issue, we first exposed adult rats to human speech sounds for 3 consecutive days, 12 h/d. Two groups of …
GLRB allelic variation associated with agoraphobic cognitions, increased startle response and fear network activation: a potential neurogenetic pathw…
2017
Contains fulltext : 177350.pdf (Publisher’s version ) (Closed access) The molecular genetics of panic disorder (PD) with and without agoraphobia (AG) are still largely unknown and progress is hampered by small sample sizes. We therefore performed a genome-wide association study with a dimensional, PD/AG-related anxiety phenotype based on the Agoraphobia Cognition Questionnaire (ACQ) in a sample of 1370 healthy German volunteers of the CRC TRR58 MEGA study wave 1. A genome-wide significant association was found between ACQ and single non-coding nucleotide variants of the GLRB gene (rs78726293, P=3.3 x 10-8; rs191260602, P=3.9 x 10-8). We followed up on this finding in a larger dimensional AC…
Neuroprotective potential of antihyperglycemic drug metformin in streptozocin-induced rat model of sporadic Alzheimer's disease.
2020
Abstract The earliest hallmarks of sporadic Alzheimer's disease (sAD) are impaired glucose metabolism, chronic neuroinflammation, diminished synaptic plasticity and subsequent cognitive decline. The safest antidiabetic drug metformin has shown both glucose metabolism-improving and cognition-enhancing action in type 2 diabetes patients and diabetic model animals. However, metformin has not been previously studied in intracerebroventricular streptozocin (STZ)-induced model of sAD. Therefore, our aim was to assess the preventive action of metformin in sAD model-rats. Firstly, the actions of metformin (75 and 100 mg/kg) on cognitive functions and sociability were examined. Secondly, we wanted t…
Hyperammonemia alters the mismatch negativity in the auditory evoked potential by altering functional connectivity and neurotransmission
2020
Minimal hepatic encephalopathy (MHE) is a neuropsychiatric syndrome produced by central nervous system dysfunction subsequent to liver disease. Hyperammonemia and inflammation act synergistically to alter neurotransmission, leading to the cognitive and motor alterations in MHE, which are reproduced in rat models of chronic hyperammonemia. Patients with MHE show altered functional connectivity in different neural networks and a reduced response in the cognitive potential mismatch negativity (MMN), which correlates with attention deficits. The mechanisms by which MMN is altered in MHE remain unknown. The objectives of this work are as follows: To assess if rats with chronic hyperammonemia rep…
GABA-containing compound gammapyrone protects against brain impairments in Alzheimer's disease model male rats and prevents mitochondrial dysfunction…
2018
Neuroinflammation, oxidative stress, decreased glucose/energy metabolism, and disrupted neurotransmission are changes that occur early in sporadic Alzheimer's disease (AD), manifesting as mild cognitive impairment. Recently, the imbalanced function of the gamma-aminobutyric acid (GABA) system was identified as a critical factor in AD progression. Thus, maintaining balance among neurotransmitter systems, particularly the GABA system, can be considered a beneficial strategy to slow AD progression. The present study investigated the effects of the compound gammapyrone, a molecule containing three GABA moieties: "free" moiety attached to the position 4 of the 1,4-dihydropyridine (DHP) ring, and…
Angiotensin II type II receptors and colonic dysmotility in 2,4-dinitrofluorobenzenesulfonic acid-induced colitis in rats
2016
Background: Angiotensin II (Ang II), the main peptide of the renin-angiotensin system (RAS), has been suggested to be involved in inflammatory bowel diseases. Since RAS has emerged as gut motility regulator, and dysmotility is associated with intestinal inflammation, our objective was to investigate in rat 2,4-dinitrobenzenesulfonic acid (DNBS)-induced colitis the functionality of RAS and its contribution to colonic motor alterations. Methods: The effects of Ang II on the longitudinal colonic muscular contractility of control and DNBS-treated rats were characterized in vitro. Transcripts encoding for Ang II receptors were investigated by RT-PCR. Key Results: Inflamed preparations showed a l…
Dopamine, Noradrenaline and Serotonin Receptor Densities in the Striatum of Hemiparkinsonian Rats following Botulinum Neurotoxin-A Injection.
2017
Abstract Parkinson’s disease (PD) is characterized by a degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) that causes a dopamine (DA) deficit in the caudate-putamen (CPu) accompanied by compensatory changes in other neurotransmitter systems. These changes result in severe motor and non-motor symptoms. To disclose the role of various receptor binding sites for DA, noradrenaline, and serotonin in the hemiparkinsonian (hemi-PD) rat model induced by unilateral 6-hydroxydopamine (6-OHDA) injection, the densities of D1, D2/D3, α1, α2, and 5HT2A receptors were longitudinally visualized and measured in the CPu of hemi-PD rats by quantitative in vitro receptor autorad…
Effects of an Antimutagenic 1,4-Dihydropyridine AV-153 on Expression of Nitric Oxide Synthases and DNA Repair-related Enzymes and Genes in Kidneys of…
2016
Development of complications of diabetes mellitus (DM), including diabetic nephropathy, is a complex multi-stage process, dependent on many factors including the modification of nitric oxide (NO) production and an impaired DNA repair. The goal of this work was to study in vivo effects of 1,4-dihydropyridine AV-153, known as antimutagen and DNA binder, on the expression of several genes and proteins involved in NO metabolism and DNA repair in the kidneys of rats with a streptozotocin (STZ)-induced model of DM. Transcription intensity was monitored by means of real-time RT-PCR and the expression of proteins by immunohistochemistry. Development of DM significantly induced PARP1 protein express…