Glutamate is a classical excitotoxin of the central nervous system (CNS), but extensive work demonstrates neuroprotective roles of this neurotransmitter in developing CNS. Mechanisms of glutamate-mediated neuroprotection are still under scrutiny. In this study, we investigated mediators of glutamate-induced neuroprotection, and tested whether this neurotransmitter controls programmed cell death in the developing retina. The protective effect of N-methyl-d-aspartate (NMDA) upon differentiating cells of retinal explants was completely blocked by a neutralizing antibody to brain-derived neurotrophic factor (BDNF), but not by an antibody to neurotrophin-4 (NT-4). Consistently, chronic activation of NMDA receptor increased the expression of BDNF and trkB mRNA, as well as BDNF protein content, but did not change the content of NT-4 mRNA in retinal tissue. Furthermore, we showed that in vivo inactivation of NMDA receptor by intraperitoneal injections of MK-801 increased natural cell death of specific cell populations of the post-natal retina. Our results show that chronic activation of NMDA receptors in vitro induces a BDNF-dependent neuroprotective state in differentiating retinal cells, and that NMDA receptor activation controls programmed cell death of developing retinal neurons in vivo.
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http://dx.doi.org/10.1111/j.1471-4159.2005.03360.x | DOI Listing |
Front Med (Lausanne)
December 2024
Social Determinants of Health Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Background: Alzheimer's disease (AD) is a chronic, progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired reasoning. It is the leading cause of dementia in older adults, marked by the pathological accumulation of amyloid-beta plaques and neurofibrillary tangles. These pathological changes lead to widespread neuronal damage, significantly impacting daily functioning and quality of life.
View Article and Find Full Text PDFArch Razi Inst
June 2024
Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Gastrointestinal dysfunction is a severe and common complication in diabetic patients. Some evidence shows that gamma-aminobutyric acid (GABA) and glutamate contribute to diabetic gastrointestinal abnormalities. Therefore, we examined the impact of prolonged treatment with insulin and magnesium supplements on the expression pattern of GABA type A (GABA-A), GABA-B, and N-methyl-D-aspartate (NMDA) glutamate receptors as well as nitric oxide synthase 1 (NOS-1) in the stomach of type 2 diabetic rats.
View Article and Find Full Text PDFNeuropharmacology
December 2024
Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, ul. Mickiewicza 2A, 15-222 Białystok, Poland.
Although angiotensin 1-7 (Ang 1-7) and its role as a part of the "protective" axis of the renin-angiotensin system are well described in the literature, the mechanisms of its angiotensin II-like pressor and tachycardic effects following its acute central administration are not fully understood. It was the aim of the present study to examine which receptors contribute to the aforementioned cardiovascular effects. Ang 1-7 and antagonists for glutamate, GABA, vasopressin, thromboxane A (TP), α-adrenergic, and P2X purinoceptors or modulators of oxidative stress were injected into the paraventricular nucleus of the hypothalamus (PVN) of urethane-anesthetized male Wistar rats.
View Article and Find Full Text PDFJ Biol Chem
December 2024
Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center; Memphis, 38163. Electronic address:
Familial Alzheimer's disease (FAD) is frequently associated with mutations in the amyloid precursor protein (APP), which are thought to lead to cognitive deficits by impairing NMDA receptor (NMDAR)-dependent forms of synaptic plasticity. Given the reliance of synaptic plasticity on NMDAR-mediated Ca entry, shaping of NMDAR activity by APP and/or its disease-causing variants could provide a basis for understanding synaptic plasticity impairments associated with FAD. A region of APP (residues 639-644 within APP695) processed by the γ-secretase complex, which generates amyloid β (Aβ) peptides, is a hotspot for FAD mutations.
View Article and Find Full Text PDFArch Pharm (Weinheim)
January 2025
Department of Pharmacognosy, University Institute of Pharma Sciences, Chandigarh University, Mohali, Punjab, India.
Alzheimer's disease (AD) is a prevalent neurological illness that affects over 80% of aged adults globally in cases of dementia. Although the exact pathophysiological causes of AD remain unclear, its pathogenesis is primarily driven by several distinct biochemical alterations: (i) the accumulation of toxic Aβ plaques, (ii) the hyperphosphorylation of tau proteins, (iii) oxidative stress resulting in cell death, and (iv) an imbalance between the two main neurotransmitters, glutamate and acetylcholine (ACh). Currently, there are very few medications available and no treatment.
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