[Effects of transcranial laser irradiation in near infrared range on antinociceptive reactions in mice after administration of diazepam, clopheline and morphine].

The experiments were carried out on white mice whose brain was irradiated transcranially with laser light in infrared range. Exposure to irradiation was 20 min. In one group of animals only laser light was used, in others laser was combined with morphine (3mg/kg), clonidine (0.5 mg/kg), and diazepam (1 mg/kg) injected intraperitoneally. The nociceptive reactions were studied with the help of "tail-flick" and "hot-plate" tests. It was found that laser light did not modify significantly the results of both tests. Moreover, it didn't influence the antinociceptive properties of morphine, clonidine and diazepam in the "hot-plate" test. In the "tail-flick" test laser light did not affect the action of clonidine, but provided naloxone-independent antinociceptive reaction with diazepam and increased the antinociceptive effect of morphine. Laser irradiation of the brain did not cause any significant morphological changes. These results suggest the possibility of modulating antinociceptive actions of morphine and diazepam by laser irradiation of the brain.