We have used mRNA differential display to isolate genes that are induc
ed by neural activity in rat hippocampus. One of these encodes activin
beta A subunit. Convulsive seizure caused by kainate significantly in
duced the expression of activin beta A mRNA, Furthermore high frequenc
y stimulation (HFS) of perforant pathway, which produced a persistent
long-term potentiation (LTP) (>10 h), caused a marked increase at 3 h
in the level of activin beta A mRNA at the dentate gyrus of urethane-a
nesthetized rat, The increase was NMDA receptor-dependent. By contrast
the level of inhibin alpha mRNA was not changed following the inducti
on of LTP. The results suggest a role for activin in maintenance of ne
ural plasticity in the adult brain.