Chronic opioid exposure induces neuroadaptative changes in several brain systems. Amongst others the alpha adrenergic system appears to be extremely sensitive to opioid exposure and has, therefore, been proposed to play a key role in opiate withdrawal symptoms. In order to better understand the influence of the noradrenergic system in opioid withdrawal and be able to develop new therapeutic strategies, we studied the effect of pre-treatment with the alpha2 agonist (clonidine) and alpha2 antagonist (yohimbine) on naloxone-precipitated withdrawal in opiate-dependent rats. As is already known clonidine pre-treatment significantly enhances autonomic and behavioural signs of opioid withdrawal whereas yohimbine significantly attenuates them with dose-related effect. We also tested the effect of clonidine (0.1 mg/kg) during naloxone-precipitated opiate withdrawal in rats pre-treated with yohimbine (5 mg/kg) and we observed that yohimbine pre-treatment potentiates clonidine efficiency in decreasing opiate withdrawal signs. This study supports the possibility of using a noradrenergic antagonist in order to regulate adrenoreceptors chronically exposed to opioids, therefore interfering with the intensity of naloxone-precipitated opiate withdrawal and potentiating later effectiveness of noradrenergic agonists like clonidine. These results may have various applications in clinical opiate detoxification protocols and are discussed through an up-/down- regulation of adrenoreceptors.
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http://dx.doi.org/10.1017/S1461145705006024 | DOI Listing |
Bioorg Chem
January 2025
School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China. Electronic address:
An alternative approach for the management of acute and chronic pains involves prolonging the half-life of endogenous opiates, such as enkephalins that are released in response to nociceptive stimuli. This can be achieved through the inhibition of enzymatic pathways responsible for the hydrolysis of these peptides, particularly targeting Aminopeptidase N (APN) and Neutral Endopeptidase (NEP). In this study, we designed and synthesized a series of dual enkephalinase inhibitors (DENKIs) targeting both APN and NEP as novel analgesic treatments.
View Article and Find Full Text PDFElife
January 2025
Department of Pharmaceutical Sciences, University of Kentucky, Lexington, United States.
Reversing opioid overdoses in rats using a drug that does not enter the brain prevents the sudden and severe withdrawal symptoms associated with therapeutics that target the central nervous system.
View Article and Find Full Text PDFJAMA Netw Open
January 2025
San Francisco Department of Public Health, San Francisco, California.
Importance: The rise of high-potency opioids such as fentanyl makes buprenorphine initiation challenging due to the risks of precipitated withdrawal, prompting the exploration of strategies, such as low-dose initiation (LDI) of buprenorphine. However, no comparative studies on LDI outcomes exist.
Objective: To evaluate outpatient outcomes associated with 2 LDI protocols of buprenorphine among individuals with opioid use disorder (OUD) using fentanyl.
Nat Commun
January 2025
Department of Pharmaceutical Sciences, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, US.
The opioid crisis, driven by synthetic opioids like fentanyl, demands innovative solutions. The opioid antidote naloxone has a short action ( ~ 1 hour), requiring repeated doses. To address this, we present a new and simple naloxone prodrug delivery system repurposing a hydrophilic derivative of acoramidis, a potent transthyretin ligand.
View Article and Find Full Text PDFPrehosp Emerg Care
January 2025
Medical College of Wisconsin, Department of Emergency Medicine.
Objectives: Medication for opioid use disorder (MOUD) reduces morbidity and mortality for patients with opioid use disorder (OUD). Recent administrative and legislative changes have made MOUD possible in the prehospital setting. We use an implementation science framework to outline the Reach of a fire department EMS-based Mobile Integrated Health (MIH) prehospital MOUD program.
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