Beschreibung:
Dendntes are the primary site of synaptic input to neurons in the CNS. They are imbued with specialized structures, such as dendritic spines, which receive much of the synaptic inputs from other neurons. They have long been considered electrically passive in that they receive nonregenerative synaptic inputs, both excitatory and inhibitory, and, through summation of passive electrotonic spread of current, they convey information in the form of membrane potential changes to the cell body and the initial axon segment, which are specialized to initiate action potentials. More than 40 years ago, this view was challenged by electrophysiological studies suggesting that dendrites can also generate action po tentials. It was proposed that these regenerative dendritic action potentials can serve as "booster" sites to assure the fidelity of synaptic signaling to the distant initial axon seg ment where nerve impulses are initiated for propagation to their terminals for signal trans mission to other neurons. Two recent articles in Science reporting the use of simultaneous patch clamp recordings from a dendrite and the cell body of rat hippocampal neurons have rekindled interest in dendrites as active generators of action potentials. In this Up date, these articles are reviewed and discussed in the context of the functional implica tions of active dendritic electrogenesis. The Neuroscientist 1:312-316, 1995