[Flavonoids from Diospyros kaki inhibit the adhesion between lymphocyte and dorsal root ganglion].

OBJECTIVE: To investigate the effects of flavonoids from the leaves of Diospyros kaki L (FLDK) on the adhesion between the lymphocyte and the neurone. METHODS: Centrifugal assay for fluorescence-bsaed cell adhesion was used to assay the adhesion between the lymphocyte and the dorsal root ganglion (DRG). RESULTS: The adhesion was significantly suppressed in the presence of FLDK dose-dependently at 5, 25 microg/mL concentration. FLDK was also effective to inhibit the adhesion under the challenge of ICAM-1 by 28.5% and 50.1%, respectively. Furthermore, FLDK enforced the inhibition of anti-NCAM antibody on the lymphocyte adhesion to DRG cells. CONCLUSION: FLDK might contribute to the prevention and treatment of the inflammation injury under neuron insult such as ischemia/reperfusion, neurotrauma and other neurodegenerative disease by inhibiting the adhesion between lymphocytes and neurons.

The neural cell adhesion molecule antibody blocks cold water swim stress-induced analgesia and cell adhesion between lymphocytes and cultured dorsal root ganglion neurons.

BACKGROUND: Opioid-containing immune cells migrate in a site-directed manner into inflamed tissue and adhere to sensory nerve fibers. These cells release opioid peptides in close proximity to these fibers, thereby avoiding localized degradation by peptidases, and delivering opioid peptides proximal to opioid receptors to provide antinociception. METHODS: The effects of the anti-neural-cell-adhesion molecule (anti-NCAM) were assessed on cold water swim stress-induced antinociception in Wistar rats with Freund's adjuvant-induced inflammation of one hindpaw. Algesiometry was assessed for both thermal and mechanical stimuli. Cell adhesion experiments examining the effects of beta-endorphin and antibodies to NCAM and intercellular cell adhesion molecule-1 and were performed on cultured dorsal root ganglion neurons and isolated lymphocytes. Lymphocyte binding was determined by fluorescence using calcein AM loaded into freshly isolated lymphocytes. RESULTS: The direct adhesion between lymphocytes and cultured sensory neurons was inhibited by anti-NCAM. This adhesion was also demonstrated to be opioid dependent, with lymphocyte adhesion to cultured sensory neurons reduced in the presence of 1 microM beta-endorphin, which was reversed by 100 microM naloxone. Moreover, anti-NCAM blocked cold-water-swim-induced analgesia in inflamed paws both to thermal and mechanical stimuli. However, anti-NCAM did not affect fentanyl-induced antinociception. CONCLUSIONS: This study provides insight into the role of cell adhesion molecules in lymphocyte adhesion to sensory neurons and a link to immune-derived antinociception.

The effects of pH on beta-endorphin and morphine inhibition of calcium transients in dorsal root ganglion neurons.

UNLABELLED: During inflammation, immune cells migrate into inflamed tissue and release opioid peptides that activate opioid receptors on peripheral sensory neurons to reduce pain. A characteristic of the inflamed environment in which these opioids act is acidic pH. Activation of opioid receptors leads to a decrease in the calcium component of neuronal action potentials. We investigated the hypothesis that inhibitory effects of opioids on intracellular calcium transients in dorsal root ganglion neuronal cultures are potentiated at acidic extracellular pH. Intracellular calcium responses to stimulation with capsaicin were measured in untreated neurons or after preincubation with beta-endorphin or morphine. beta-Endorphin significantly inhibited calcium responses to 300 nmol/L capsaicin at the lowest experimental extracellular pH (6.1, 6.5, and 7.2), whereas morphine inhibited capsaicin (300 nmol/L) responses significantly at pH 6.1 with a trend of inhibition at pH 6.5. The effect of pH on morphine inhibition of K+ -evoked calcium responses was also assessed. Morphine inhibition of calcium responses was significantly enhanced at pH 6.8 compared with pH 7.2 and pH 7.6. The inhibitory effects were reversed by naloxone, an opioid receptor antagonist. In conclusion, low extracellular pH potentiated beta-endorphin and morphine inhibition of calcium transients and might contribute to improved opioid efficacy during inflammation. PERSPECTIVE: The results of the current study suggest that acidic pH might contribute to increased opioid efficacy in inflamed tissue. This highlights the therapeutic potential of endogenous opioid analgesia, whereby opioid peptides are delivered locally in inflamed tissues, as well as the use of locally applied opioids in inflammatory conditions.

Reduction of beta-endorphin-containing immune cells in inflamed paw tissue corresponds with a reduction in immune-derived antinociception: reversible by donor activated lymphocytes.

UNLABELLED: The functional integrity of the immune system is essential for peripheral antinociception. Previous studies have demonstrated that immune cells elicit potent antinociception in inflamed tissues and that corticotropin-releasing factor-induced antinociception is significantly inhibited in animals that have undergone cyclosporin A (CsA)-induced immunosuppression. In this study, we examined the effect of a single bolus of CsA on inflammatory nociception. CsA-treated rats had substantially increased nociception compared with nonimmunosuppressed rats, consistent with a reduction in circulating and infiltrating lymphocytes. Furthermore, CsA-treated rats had inhibition of corticotropin-releasing factor-induced immune-derived antinociception, which was dose-dependently reversed by IV injection of concanavalin A-activated donor lymphocytes (1.0-7.0 x 10(6) cells/0.1 mL). In conclusion, our findings provided further evidence that opioid-containing immune cells are essential for peripheral analgesia. It is evident from these findings that control of inflammatory pain relies heavily on a functioning immune system. IMPLICATIONS: The immune system not only contributes to inflammation, but also provides localized analgesia. A depleted immune system results in a reduction of immune-derived analgesia and a potentiation of inflammatory pain. Donor activated lymphocytes reverse these effects, highlighting the importance of a functional immune system in inflammatory pain.

Localization of taurine transporters, taurine, and (3)H taurine accumulation in the rat retina, pituitary, and brain.

The nervous system contains an abundance of taurine, a neuroactive sulfonic acid. Antibodies were generated against two cloned high-affinity taurine transporters, referred to in this study as TAUT-1 and TAUT-2. The distribution of such was compared with the distribution of taurine in the rat brain, pituitary, and retina. The cellular pattern of [(3)H] taurine uptake in brain slices, pituitary slices, and retinas was examined by autoradiography. TAUT-2 was predominantly associated with glial cells, including the Bergmann glial cells of the cerebellum and astrocytes in brain areas such as hippocampus. Low-level labeling for TAUT-2 was also observed in some neurones such as CA1 pyramidal cells. TAUT-1 distribution was more limited; in the posterior pituitary TAUT-1 was associated with the pituicytes but was absent from glial cells in the intermediate and anterior lobes. Conversely, in the brain TAUT-1 was associated with cerebellar Purkinje cells and, in the retina, with photoreceptors and bipolar cells. Our data suggest that intracellular taurine levels in glial cells and neurons may be regulated in part by specific high-affinity taurine transporters. The heterogeneous distribution of taurine and its transporters in the brain does not reconcile well with the possibility that taurine acts solely as a ubiquitous osmolyte in nervous tissues.