Selectins and integrins but not platelet-endothelial cell adhesion molecule-1 regulate opioid inhibition of inflammatory pain.

1. Control of inflammatory pain can result from activation of opioid receptors on peripheral sensory nerves by opioid peptides secreted from leukocytes in response to stress (e.g.

Endogenous peripheral antinociception in early inflammation is not limited by the number of opioid-containing leukocytes but by opioid receptor expression.

Endogenous inhibition of inflammatory pain is mediated by leukocytes that secrete opioid peptides upon exposure to stress (cold water swim stress, CWS) or after local injection of corticotropin releasing factor (CRF). Since in early inflammation few opioid-containing leukocytes are detected and since peripheral opioid-mediated antinociception is low we examined whether antinociception could be augmented by increased recruitment of opioid-containing polymorphonuclear cells (PMN). Rats were intraplantarly (i.

Infraspinatus muscle atrophy in professional baseball players.

Background: Infraspinatus muscle atrophy has been observed in athletes who stress their upper extremities in an overhead fashion. The majority of such case reports have been in volleyball players, with far fewer cases reported in baseball players.

Hypothesis: Infraspinatus muscle atrophy occurs to a notable degree in professional baseball players.

Mobilization of opioid-containing polymorphonuclear cells by hematopoietic growth factors and influence on inflammatory pain.

Background: Leukocytes can control inflammatory pain by secretion of opioid peptides, stimulated by cold-water swimming or local injection of corticotropin-releasing factor, and subsequent activation of opioid receptors on peripheral sensory neurons. This study investigated whether mobilization of polymorphonuclear cells (PMN) by granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) enhances immigration of opioid-containing PMN and peripheral opioid analgesia in rats with Freund complete adjuvant-induced hind paw inflammation.

Methods: In circulating PMN of rats treated with G-CSF+SCF and sham-treated rats, opioid peptide content was measured by radioimmunoassay.

Involvement of corticotropin-releasing hormone receptor subtypes 1 and 2 in peripheral opioid-mediated inhibition of inflammatory pain.

In painful inflammation, exogenous as well as endogenous corticotropin-releasing hormone (CRH) can release opioid peptides (mainly beta-endorphin) from various types of immune cells and produce antinociception by activating opioid receptors on peripheral sensory nerve endings. CRH mediates its central effects through two high-affinity membrane receptors, the CRH receptor subtypes 1 and 2. It is unclear at present whether the peripheral antinociceptive effects of CRH are mediated through CRH receptor 1 (CRH R1) or CRH receptor 2 (CRH R2).

Subcellular pathways of beta-endorphin synthesis, processing, and release from immunocytes in inflammatory pain.

The opioid peptide beta-endorphin (END) as well as mRNA for its precursor proopiomelanocortin (POMC) are found not only in the pituitary gland, but also within various types of immune cells infiltrating inflamed sc tissue. During stressful stimuli END is released and interacts with peripheral opioid receptors to inhibit pain. However, the subcellular pathways of POMC processing and END release have not yet been delineated in inflammatory cells.

Characterization of mu opioid receptor binding and G protein coupling in rat hypothalamus, spinal cord, and primary afferent neurons during inflammatory pain.

Peripheral analgesic effects of opioids are pronounced under inflammatory conditions, e.g., arthritis; however, little is known about adaptive changes of micro opioid receptor binding and G protein coupling in the peripheral versus central nervous system.

Different mechanisms of intrinsic pain inhibition in early and late inflammation.

Neuroimmune interactions control pain through activation of opioid receptors on sensory nerves by immune-derived opioid peptides. Here we evaluate mechanisms of intrinsic pain inhibition at different stages of Freund's adjuvant-induced inflammation of the rat paw. We use immunohistochemistry and paw pressure testing.

Thoracic epidural anesthesia attenuates hemorrhage-induced impairment of intestinal perfusion in rats.

Background: During hemorrhagic hypotension, sympathetic vasoconstriction crucially contributes to gut mucosal damage. Sympathetic blockade by thoracic epidural anesthesia has been shown to increase mucosal microvascular perfusion and to improve survival after severe hemorrhage in laboratory animals. This study investigates the effects of thoracic epidural anesthesia on intestinal microvascular perfusion during hemorrhagic hypotension in rats.

Attacking pain at its source: new perspectives on opioids.

The treatment of severe pain with opioids has thus far been limited by their unwanted central side effects. Recent research promises new approaches, including opioid analgesics acting outside the central nervous system, targeting of opioid peptide-containing immune cells to peripheral damaged tissue, and gene transfer to enhance opioid production at sites of injury.

Muscle flap salvage of spine wounds with soft tissue defects or infection.

Study Design: This retrospective study was designed to analyze the results of 22 patients treated for postoperative soft tissue defects of the spine.

Objective: To demonstrate the utility of flaps in the salvage of spine wounds.

Summary Of Background Data: In the literature, the treatment of postoperative spine infections is with serial débridement, antibiotic irrigation catheters, drains, and occasional removal of spinal implants.

Cytokines and peripheral analgesia.

Tissue damage causes an inflammatory response in which cytokines contribute to a painful state. Local inflammation also leads to an enhanced expression of opioid peptides such as END within immune cells of inflamed tissue. These endogenous substances can be released by "releasing factors" such as CRF and IL-4 via activation of their receptors on the cell surface of inflammatory cells.

Modulation of peripheral endogenous opioid analgesia by central afferent blockade.

Background: Peripheral tissue injury causes a migration of opioid peptide-containing immune cells to the inflamed site. The subsequent release and action of these peptides on opioid receptors localized on peripheral sensory nerve terminals causes endogenous analgesia. The spinal application of opioid drugs blocks the transmission of nociceptive information from peripheral injury.

Opioid control of inflammatory pain regulated by intercellular adhesion molecule-1.

Pain can be effectively controlled by endogenous mechanisms based on neuroimmune interactions. In inflamed tissue immune cell-derived opioid peptides activate opioid receptors on peripheral sensory nerves leading to potent analgesia. This is brought about by a release of opioids from inflammatory cells after stimulation by stress or corticotropin-releasing hormone (CRH).

Immunohistochemical localization of endomorphin-1 and endomorphin-2 in immune cells and spinal cord in a model of inflammatory pain.

Recently, two novel highly selective mu-opioid receptor (MOR) agonists, endomorphin-1 and endomorphin-2, have been isolated from bovine as well as human brains and were proposed to be the endogenous ligand for MOR. Later, endomorphin-1 and endomorphin-2 have been detected in the immune system of rats and humans using radioimmunoassay in combination with reverse-high-phase-liquid chromatography. In the present study, we analyzed the expression of endomorphin-1, endomorphin-2 and MOR by immunohistochemistry in a model of Freund's complete adjuvant (FCA)-induced painful inflammation.

Disease-associated mutations in L1 CAM interfere with ligand interactions and cell-surface expression.

Mutations in the L1CAM gene cause a highly variable neurological disease described as X-linked hydrocephalus, MASA syndrome or spastic paraplegia type I. Over one-third of the mutations identified in affected boys are missense, unique to individual families and distributed primarily across the large extracellular domain of the L1 protein. We have examined the effects of 25 missense mutations on binding to homophilic (L1) and heterophilic (TAX-1) ligands as well as on intracellular trafficking.

Methionine-enkephalin-and Dynorphin A-release from immune cells and control of inflammatory pain.

We have previously shown that beta-endorphin (END) is contained and released from memory-type T-cells within inflamed tissue and that it is capable to control pain (J Clin Invest 100(1) (1997) 142). Methionine-enkephalin (MET) and Dynorphin-A (DYN) are endogenous opioids with preference for delta- and kappa-opioid receptors, respectively. Both MET and DYN are produced and contained within immune cells.