TRH analogue antagonizes anaesthetic induced depression of information transfer through the ventrobasal thalamus of the rat.

Previous studies have indicated an anti-narcotic action of TRH and its analogues. A major site of anaesthetic action is in the ventrobasal thalamus (VBT). The present experiments were performed to determine whether there was antagonism between anaesthetics and a TRH analogue on VBT transmission. It was found that the TRH analogue CG3703 reversed the depressant actions of the anaesthetics urethane, sodium pentobarbitone and sodium brietal on ventrobasal transmission. These actions were also observed at the cortical level but cuneate transmission was unaffected. These results are discussed in the context of modulation of information flow through VBT. In particular it is suggested that TRHergic input from the thalamic reticular nucleus may be an important regulator of VBT transmission.