In this study, the effects of subcutaneous (SC) injection of pilocarpine (a cholinomimetic agent) and atropine (a muscarinic receptors antagonist) were investigated on a tonic model of orofacial pain in rats. The contribution of the endogenous analgesic opioid system was assessed using naloxone (an opioid receptors antagonist). Tonic orofacial pain was induced by SC injection of a diluted forma...

Introduction: Some evidence demonstrates endogenous inhibitory pathways of pain involved in the interphase (phase between early and later phase) of the formalin test. We previously showed that swimming stress modulates the pain-related behaviors during the interphase of the formalin test. In this study, we evaluated the role of the endogenous opioid system in modulating nociceptive responses of...

The opioid systems play an important role in mediating both physical pain and negative affects (eg, the pain of social isolation). From an evolutionary perspective, it is not surprising that the neurocircuitry and neurochemistry of physical pain would overlap with that involved in complex social emotions. Exposure to trauma as well as a range of gene variants in the opioid system may be associa...

Opioid drugs like morphine and fentanyl are the gold standard for treating moderate to severe acute and chronic pain. However, opioid drug use can be limited by serious side effects, including constipation, tolerance, respiratory suppression, and addiction. For more than 100 years, we have tried to develop opioids that decrease or eliminate these liabilities, with little success. Recent advance...

The NOP receptor (nociceptin/orphanin FQ opioid peptide receptor) is the most recently discovered member of the opioid receptor family and, together with its endogenous ligand, N/OFQ, make up the fourth members of the opioid receptor and opioid peptide family. Because of its more recent discovery, an understanding of the cellular and behavioral actions induced by NOP receptor activation are les...

www.aafp.org/afp Volume 82, Number 6 ◆ September 15, 2010 Methylnaltrexone (Relistor) is labeled for the treatment of opioid-induced constipation in patients with advanced illness who have not responded to laxative therapies.1 As a selective antagonist of peripheral mu-opioid receptors, methylnaltrexone inhibits opioidinduced gastrointestinal (GI) hypomotility without central nervous system eff...

chronic pain is a prevalent and debilitating condition, conveying immense human burden. suffering from chronic pain is not only caused by painful symptomatology, but also through a wide range of psychopathological and physical consequences, including depression and anxiety disorders, impaired sleep and cognition, cardiovascular morbidity and impaired sexual function, all contributing to diminis...

The Drug Addiction Treatment Act of 2000 (DATA 2000) was established to create a new paradigm for medication-assisted treatment of persons with opiate addiction in the United States. Before enactment of DATA 2000, the use of opioid medications to treat patients with opioid addiction was permissible only in federally approved treatment programs, ie, "methadone clinics." The only medications perm...

The opioid receptors (ORs) are known to be distributed widely in the central nervous system (CNS) and in peripheral sensory and autonomic nerves. Activation of ORs by endogenous and exogenous ligands results in a multitude of physiological functions and behaviors, e.g. pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, and many more...

INTRODUCTION Zinc chelators were shown to facilitate some opioid-withdrawal signs in animals. Zinc deficiency, which affects more than 15% the world's population, is also common among opioid consumers and opioid-treated animals exhibit misbalances of zinc distribution. AIM The present study focuses on how zinc ions interfere with opioid dependence/addiction and analgesia, trying to preliminar...