Influence of ambient temperature and drug treatments on brain oedema induced by impact injury on skull in rats.

The progression and persistence of oedema development following impact-injury on closed skull was studied in anaesthetised as well as in unanaesthetised rats. The degree and rate of oedema development, following trauma, was aggravated in anaesthetised hypothermic animals but was reduced/or delayed by maintenance of body temperature at euthermic level. In general, the unanaesthetised animals showed a greater accumulation of oedema fluid than the corresponding anaesthetised group. The development of oedema corresponded more or less with the accumulation of 5-HT level in plasma and brain. This development of oedema was completely prevented following pretreatment with p-CPA, indomethacin paracetamol and aminophylline in unanaesthetised animals; whereas these drugs were able only to partially reduce the oedema development in euthermic anaesthetised animals. On the other hand the cyproheptadine pretreatment aggravated the oedema development which was more pronounced in unanaesthetised animals. The probable mechanism of the action of these drugs has been discussed.