It has been hypothesized that, in the absence of acute or chronic pain, a tonically active system exists involving opioid peptides, which ensures a certain level of pain insensitivity. Although various studies have failed to support this concept, it has been reported that in conditions of both experimentally induced and clinical pain, high doses of the opioid antagonist naloxone induced a state of hyperalgesia and thus seemed to set off this hypothetical system. Lower doses were, however, without effect or even acted as analgesics. This study investigated the effect of 5 and 20 mg naloxone i.v., compared to placebo, on the perception of pain in healthy humans. Pain was induced by two methods, using electrical and thermal stimulation of the skin, which have previously been shown to be sensitive to the effects of opioid as well as of non-steroidal anti-inflammatory analgesics. Each of 12 males and 12 females participated in 3 experimental sessions, in which the treatments were administered double-blind according to a Latin square design. Threshold and tolerance to electrically induced pain and threshold to thermally induced pain were measured at 30 min intervals for 90 min before and 90 min after drug administration. Electrical stimuli were square wave constant current impulses of linearly increasing intensity; thermal stimuli were of constant intensity and variable duration. Threshold and tolerance to electrically induced pain were not altered by either dose of naloxone, whereas the threshold to thermally induced pain was significantly higher after both 5 and 20 mg naloxone than after placebo, the effects of the two naloxone doses not differing from each other.(ABSTRACT TRUNCATED AT 250 WORDS)

Besprechung bisheriger Arbeiten. Festlegung des Gleichgewichts des „reinen Systems‟ bei 1600°. Einfluß von Kohlenstoff und Silizium auf die Lage des Gleichgewichts. Temperaturabhängigkeit der gewählten Gleichgewichtskonstanten. Schlußfolgerungen.

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Einfluß von Glühtemperatur, Glühdauer, Wanddicke, Zusammensetzung und Strömungsgeschwindigkeit des Gasgemisches auf die Entkohlungsgeschwindigkeit bei normalem Temperrohguß. Wirkung des Ausgangskohlenstoffgehaltes im Rohguß sowie Einfluß von Mangan, Chrom, Molybdän und Vanadin auf die Entkohlungsgeschwindigkeit. Bestimmung der Diffusionskonstanten von Kohlenstoff im Eisen. Reaktionsmechanismus zwischen Glühgut und Gasphase beim entkohlenden Glühen.