THE CELLULAR MECHANISMS OF HIPPOCAMPAL LONG-TERM DEPRESSION

We have examined the initial steps and biochemical mechanisms for the induction of long-term depression (LTD) in CA1 hippocampal pyramidal c ells using prolonged low frequency (1 Hz) afferent stimulation. This f orm of LTD was shown to be synapse specific, require activation of pos tsynaptic NMDA receptors and require a change in postsynaptic calcium concentration. Application of specific inhibitors of protein phosphata se 1 and 2A and calmodulin antagonists blocked or attenuated the induc tion of LTD, respectively. These findings indicate that synaptic activ ation of protein phosphatases may play an important role in the induct ion of homosynaptic LTD.