Signal transduction in LPS-activated aged and young monocytes.

Aged monocytes, that is, monocytes purified from the blood of donors > or =65 years of age, when compared with young monocytes, that is, monocytes purified from the blood of young donors 25 years of age, display a decrease in interleukin-6 (IL-6) and tumor necrosis factor (TNF) production after activation by lipopolysaccharide (LPS). The LPS concentration required to obtain IL-6 and TNF production is much higher for aged monocytes than for young monocytes. Furthermore, the intensity of TNF and IL-6 production was much weaker for LPS-activated aged monocytes than for LPS-activated young monocytes.

Kinetic properties of nitric oxide synthase in cerebral cortex and cerebellum of morphine tolerant mice.

The effects of chronic morphine administration on the kinetics of nitric oxide synthase (NOS) activity were determined in the mouse cerebral cortex and cerebellum. Male Swiss-Webster mice were implanted subcutaneously with morphine pellets each containing 25 mg of morphine base for 3 days. Mice implanted with placebo pellets served as controls.

Differential expression of the melatonin receptor in human monocytes.

Earlier studies have shown that the pineal hormone melatonin activates human monocytes. It is reported here that melatonin induces the secretion of IL-1, IL-6, and TNF in fresh and 1-day in vitro cultured monocytes that also express the melatonin receptor (Kd = 270 +/- 60 pM; 42,000-48,000 receptors/cell). However, when monocytes were cultured in vitro for 2 days, the number of receptors decreased to 11,000 receptors/cell, with the same Kd.

Activation of human monocytes by LPS and DHEA.

Dehydroepiandrosterone (DHEA) alone, whatever the concentration used, or lipopolysaccharide (LPS) alone at 0.2 ng/ml did not induce the release of interleukin-6 (IL-6) or tumor necrosis factor (TNF) by human monocytes. However DHEA (10[-9] M or 10[-12] M) in association with LPS (0.

Relationship between morphine analgesia and cortical extracellular fluid levels of morphine and its metabolites in the rat: a microdialysis study.

1. The effect of morphine (10 mg kg-1, s.c.