Administration of methionine enkephalin (ICV) to rats for 5 days resulted in the development of physical dependence as exemplified by a hypothermic response which peaked 2-8 hours after initiation of withdrawal. Twenty-four hours post-withdrawal, opioid receptor binding was determined in the striatum using a selective delta receptor ligand. These studies revealed a decreased in the number of receptors. Bmax decreased from 193 +/- 20.4 fmoles/mg protein in controls to 136 +/- 9.7 fmoles/mg protein in enkephalin treated rats. This difference is significant at p less than 0.001. Existing evidence suggests that this decrease in binding is predominantly due to a decrease in delta receptors. Hence, the present findings indicate that delta receptor down-regulation in vivo may be an important mechanism in the adaptive response to chronic exposure to an endogenous opioid peptide.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0361-9230(86)90123-1 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Green Synthesis of Tetrahydropyrazino[2,1-a:5,4-a']diisoquinolines as SARS-CoV-2 Entry Inhibitors.
ACS Omega
January 2025
Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan.
A class of tetrahydropyrazino[2,1-a:5,4-a']diisoquinoline derivatives were synthesized under environmentally friendly conditions using water as the solvent. The 3-D structures of some synthesized compounds were determined by X-ray diffraction. Since naturally occurring isoquinoline alkaloids have significant antiviral activities against a wide range of viruses, including coronaviruses, the synthesized compounds were assayed for their inhibitory activities against SARS-CoV-2.
View Article and Find Full Text PDFDesign, synthesis, and biological evaluation of imidazolidinone derivatives as potent PPARα/δ agonists for the treatment of cholestatic liver diseases.
Eur J Med Chem
January 2025
Jiangsu Key Laboratory of Drug Discovery for Metabolic Disease, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China. Electronic address:
Cholestatic liver disease (CLD) represents a significant and growing public health concern, and there is a lack of effective therapeutic drug in clinical practice. Peroxisome proliferator-activator receptors α/δ (PPARα/δ) are regarded as potential therapeutic targets for CLD. In this study, a series of novel imidazolidinone PPARα/δ agonists were developed, and the preferred compound 8 displayed potent and well-balanced agonistic activity.
View Article and Find Full Text PDFSpecific selection of stimulation-responsive γδ T-cells utilizing a short-term activation assay.
Methods Cell Biol
January 2025
Institute of Immunology, Christian-Albrechts University and University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany. Electronic address:
T cells expressing the γδ T-cell receptor (TCR) represent a numerically small proportion of total T cells. Unlike αβ T cells they are activated by non-peptide antigens independently of MHC-presentation. γδ T cells have been recognized as a favorable prognostic marker across different tumor entities.
View Article and Find Full Text PDFMuscarinic cannabinoid suppression of excitation, a novel form of coincidence detection.
Pharmacol Res
January 2025
Gill Institute for Neuroscience; Dept. of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405. Electronic address:
Δ-tetrahydrocannabinol (THC), the chief psychoactive ingredient of cannabis, acts in the brain primarily via cannabinoid CB1 receptors. These receptors are implicated in several forms of synaptic plasticity - depolarization-induced suppression of excitation (DSE), metabotropic suppression of excitation (MSE), long term depression (LTD) and activation-dependent desensitization. Cultured autaptic hippocampal neurons express all of these, illustrating the rich functional and temporal heterogeneity of CB1 at a single set of synapses.
View Article and Find Full Text PDFThe histamine pathway is a target to treat hepatic experimental erythropoietic protoporphyria.
Cell Mol Gastroenterol Hepatol
January 2025
Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA. Electronic address:
Background & Aims: Erythropoietic protoporphyria (EPP) is caused by mutations in ferrochelatase which inserts iron into protoporphyrin-IX (PP-IX) to generate heme. EPP is characterized by PP-IX accumulation, skin photosensitivity, cholestasis, and end-stage liver disease. Despite available drugs that address photosensitivity, treatment of EPP-related liver disease remains an unmet need.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!