ERK plays a regulatory role in induction of LTP by theta frequency stimulation and its modulation by beta-adrenergic receptors

MAP kinase (ERK) translates cell surface signals into alterations in transc ription. We have found that ERK also regulates hippocampal neuronal excitab ility during 5 Hz stimulation and thereby regulates forms of long-term pote ntiation (LTP) that do not require macromolecular synthesis. Moreover, ERK- mediated changes in excitability are selectively required for some forms of LTP but not others. ERK is required for the early phase of LTP elicited by brief 5 Hz stimulation, as well as for LTP elicited by more prolonged 5 Hz stimulation when paired with beta 1-adrenergic receptor activation. By con trast, ERK plays no role in LTP elicited by a single 1 s 100 Hz train. Cons istent with these results, we find that ERK is activated by beta-adrenergic receptors in CA1 pyramidal cell somas and dendrites.