PRESYNAPTIC INHIBITION IN THE HIPPOCAMPUS

Presynaptic receptors for virtually all transmitters have been identif ied throughout the nervous system. Recent studies in the hippocampus p rovide new insights into the mechanisms by which the activation of the se receptors leads to presynaptic inhibition of transmitter release, a nd characterize the second messengers involved in coupling presynaptic receptors to their effectors. Presynaptic receptors also provide a tr actable route via which the amount of transmitter release may be selec tively regulated in therapeutically useful ways.