TRH analogue affects information transfer through the ventrobasal thalamus.

Extracellular microelectrode recordings have been made from single ventrobasal thalamic neurones in rats anaesthetised with urethane. Injection of the thyrotropin releasing hormone (TRH) analogue RX77368 (2mg/kg), produced increases in spontaneous activity and decreases in the latency of response to peripheral stimulation, together with increased production of later, rhythmic discharges. These changes were maximal between 30 and 60 minutes after injection. Decreases in latency and increases in amplitude were also observed in the evoked potential recorded from the somatosensory cortex. These results are discussed in relation to previously observed effects of TRH. Since this system is important in the planning and execution of motor acts it is suggested that modification of information flow through this system could have effects on the production of motor activity.