Neurotrophins 3 and 4 enhance non-rapid eye movement sleep in rabbits.

We determined if neurotrophins 3 and 4 (NT-3, NT-4) would promote sleep in rabbits. Two doses of NT-3 (50 and 500 ng) and three doses of NT-4 (50, 500 and 2000 ng) were intracerebroventricularly injected at dark onset. Additionally, 500 ng of each NT were injected during the light period. The electroencephalogram (EEG), brain temperature, and motor activity were recorded for 23 h following NT injection. NT-3 (500 ng dose) and NT-4 (500 and 2000 ng doses) injected at dark onset increased the time spent in non-rapid eye movement sleep. After the 2000 ng dose of NT-4, EEG power was reduced.