EEG measurements by means of radiotelemetry after intracerebroventricular (ICV) cannulation in rodents

The utility of implanted radiotelemetry transmitters for the measurement of electroencephalogram (EEG), locomotor activity, body temperature and cardiovascular parameters has been well documented. This paper focuses on the methodology, of combining radiotelemetry with intracerebroventricular (ICV) cannulation. The two excitatory neuropeptides, orexin-A and orexin-B, can only be given by ICV injection, therefore we examined their effects on the normal sleep-wake cycle of rodents in the present study. The effects of orexins on sleep architecture have been extensively studied in tethered models demonstrating increased levels of wakefulness. In this study, both orexin neuropeptides, especially orexin-A, increase wakefulness within the first sleep period followed by an increase in slow wave (SW) sleep and paradoxical sleep (PS), towards the end of a 5-h recording period which may be a rebound phenomena. The present study has demonstrated that ICV cannulation can be used effectively in studying the effects of pharmacological agents on the sleep-wake cycle of rodents by measuring EEG and EMG by radiotelemetry.