Reversal of drug-induced hyperalgesia by transient hyperglycaemia

ABSTRACT

This study was conducted to assess the effect of transient hyperglycemia on drug-induced hyperalgesia. The study included male mice [18-25 g] randomly divided into groups of six to eight animals. Nociceptive sensitivity was estimated by the hot-plate assay [50C]. Naloxone per se exerted hyperalgesic activity at 0.5 and 4 mg/kg, whereas the middle dose [2 mg/kg] produced a slight increase in nociceptive threshold. Yohimbine produced a biphasic response, i.e. it induced significant hyperalgesic effect in the lower dose range and marked elevation in nociceptive threshold in the highest dose. On the other hand, atropine produced consistent and dose dependent hyperalgesic effect. The hyperalgesic responses induced by all three antagonists were uniformly reversed by transient hyperglycemia. The findings regarding naloxone would suggest that it would be valuable in dealing with painful diabetic neuropathy