Antinociceptive potency of opioids is greater against various noxious stimuli
in animals with peripheral inflammation. Opioid agonists stimulate activation
of G-protein-coupled receptor. Changes in the resting levels of G-protein subtypes
could have an effect on intracellular signalling pathways. The present
study was designed to investigate the effects of analgesic morphine treatment
on the level G-protein subunits mRNA in the presence and absence of inflammation.
Our results showed that the carrageenan administration increased
G-protein subunits. Administration of analgesic dose of morphine alone and in
the presence of inflammation induced different alterations in the levels of
G-protein mRNA. Taken together, the results obtained using real time
RT-PCR suggested that G-protein genes expression levels following the acute
administration of morphine between animals with and without inflammation
could influence, at least in part, analgesic responsiveness.
