The long-term inhibition by strychnine of glycine receptor activity in neurons provokes the receptor's selective intracellular accumulation and disappearance from synapses. This could result either from a disruption of the postsynaptic anchoring of the receptor or from an arrest of its exocytic transport. In this study we combined biochemical and fluorescence microscopy analyses to determine on a short time scale the fate of the strychnine-inactivated glycine receptor. Quantification of the cellular content of receptor showed that the rapid accumulation depends on protein synthesis. Cell surface biotinylation of neurons demonstrated that strychnine did not accelerate the turnover rate of the receptor. Labeling of endosomes indicated that, in strychnine-treated cells, the accumulated receptor is not blocked in the endosomal transport pathway. Taken together, these results indicate that strychnine does not destabilize the postsynaptic receptor but triggers its disappearance from synapses by a nondegradative sequestration of newly synthesized molecules in a nonendocytic compartment.
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http://dx.doi.org/10.1006/mcne.2001.1074 | DOI Listing |
Neurogenetics
January 2025
Department of Biochemistry, College of Medicine, University of Lagos, Lagos State, Nigeria.
Schizophrenia (SZ) is a complex, chronic mental disorder characterized by positive symptoms (such as delusions and hallucinations), negative symptoms (including anhedonia, alogia, avolition, and social withdrawal), and cognitive deficits (affecting attention, processing speed, verbal and visuospatial learning, problem-solving, working memory, and mental flexibility). Extensive animal and clinical studies have emphasized the NMDAR hypofunction hypothesis of SZ. Glycine plays a crucial role as an agonist of NMDAR, enhancing the receptor's affinity for glutamate and supporting normal synaptic function and plasticity, that is, signal transmission between neurons.
View Article and Find Full Text PDFInt J Neuropsychopharmacol
January 2025
Neurocrine Biosciences, Inc., San Diego, CA.
Hypofunction of the N-methyl-D-aspartate receptor (NMDAR) has been proposed to underlie the pathophysiology of schizophrenia, suggesting that promoting NMDAR activity may alleviate the negative or cognitive symptoms associated with schizophrenia. To circumvent excitotoxicity that may accompany direct agonism of the glutamate binding site on the NMDAR, therapeutic trials have focused on targeting the glycine binding site on the NMDAR. Direct administration of either glycine or D-serine, both of which are endogenous coagonists at the NMDAR glycine site, has yielded mixed outcomes across an array of clinical trials investigating different doses or patient populations.
View Article and Find Full Text PDFMol Med Rep
March 2025
Department of Orthopedics, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China.
Aseptic loosening (AL) of artificial hip joints is the most common complication following hip replacement surgery. A total of eight patients diagnosed with AL following total hip arthroplasty (THA) undergoing total hip replacement and eight control patients diagnosed with avascular necrosis of femoral head (ANFH) or femoral neck fracture undergoing THA were enrolled. The samples of the AL group were from synovial tissue surrounding the lining/head/neck of the prosthesis, and the samples of the control group were from the synovium in the joint cavity.
View Article and Find Full Text PDFNeuropsychiatr Dis Treat
December 2024
Department of Medicine and Surgery, Kore University of Enna, Enna (EN), Italy.
Vet Sci
November 2024
Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou 225012, China.
Pigeon Newcastle disease (ND) is the most common viral infectious disease in the pigeon industry, caused by pigeon paramyxovirus type 1 (PPMV-1), a variant of chicken-origin Newcastle disease virus (NDV). Previous studies have identified significant amino acid differences between PPMV-1 and chicken-origin NDV at positions 347 and 349 in the hemagglutinin-neuraminidase (HN) protein, with PPMV-1 predominantly exhibiting glycine (G) at position 347 and glutamic acid (E) at position 349, while most chicken-origin NDVs show E at position 347 and aspartic acid (D) at position 349. However, the impact of these amino acid substitutions remains unclear.
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