The mu opioid receptor system is altered in alcohol dependent (AD) subjects. Cortisol responses to opioid receptor antagonists are assumed to impart information about opioid receptor activity. In the present study we examined naloxone-induced cortisol responses in 18 healthy control (HC) and 25 recently detoxified AD subjects and then correlated the cortisol response with mu opioid receptor ava...

Placebo-induced expectancies have been shown to decrease pain in a manner reversible by opioid antagonists, but little is known about the central brain mechanisms of opioid release during placebo treatment. This study examined placebo effects in pain by using positron-emission tomography with [11C]carfentanil, which measures regional -opioid receptor availability in vivo. Noxious thermal stimul...

BACKGROUND Human affective responses appear to be regulated by limbic and paralimbic circuits. However, much less is known about the neurochemical systems engaged in this regulation. The mu-opioid neurotransmitter system is distributed in, and thought to regulate the function of, brain regions centrally implicated in affective processing. OBJECTIVE To examine the involvement of mu-opioid neur...

OBJECTIVES To review the definitions and scientific basis for opioid tolerance and dependence in neonates and older children; to assess objective methods for the clinical evaluation of opioid abstinence syndromes in this age group; and to suggest therapeutic strategies for the treatment of opioid abstinence in critically ill neonates and children. DATA SOURCES The published literature on opio...

Opioid analgesics are the mainstay in the treatment of moderate-to-severe pain, yet their use is frequently associated with adverse effects, the most common and debilitating being constipation. Opioid-induced motor stasis results from blockade of gastrointestinal peristalsis and fluid secretion, and reflects the action of the endogenous opioid system in the gut. Methylnaltrexone and alvimopan a...

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 1. Physiological Control of Gastrointestinal Motility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651 1.1 Stimulation of Gastrointestinal Contractions . . . . . . . . . . . . . . . ...

Biogenesis of various endogenous opioid peptides, anatomical distribution and the characteristics of multiple receptors with which they interact provides an opportunity for understanding the role of opioid systems and mechanism of opioid tolerance. Cellular and anatomical distribution of opioid receptor and their function is important for identification of neuronal systems and local network inv...

Opioid receptors mediate the strong analgesic and addictive actions of exogenous opiates, the prototype of which is morphine. The opioid system consists of a family of endogenous opioid peptides and three receptor types, m, d and k. It is widely distributed throughout the CNS and regulates a large diversity of physiological functions, including pain perception and mood control. The recent cloni...

μ-Opioid agonists mediate their analgesic effect through GPCRs that are generated via alternate splicing of the Oprm1 transcript. While the majority of μ-opioids interact with receptors comprising the canonical 7 transmembrane (7TM) domain, a recently identified class of μ-opioids appears to require a 6TM domain variant. In this issue of the JCI, Lu and colleagues provide an in vivo proof-of-co...