|
Dendrodendritic synapses are connections between the dendrites of two different neurons. This is in contrast to the more common axodendritic synapse (chemical synapse) where the axon sends signals and the dendrite receives them. Dendrodendritic synapses are activated in a similar fashion to axodendritic synapses in respects to using a chemical synapse. These chemical synapses receive a depolarizing signal from an incoming action potential which results in an influx of calcium ions that permit release of Neurotransmitters to propagate the signal the post synaptic cell. There is also evidence of bi-directionality in signaling at dendrodendritic synapses. Ordinarily, one of the dendrites will display inhibitory effects while the other will display excitatory effects. The actual signaling mechanism utilizes Na+ and Ca2+ pumps in a similar manner to those found in axodendritic synapses. ==History== In 1966 Wilfrid Rall, Gordon Shepard, Thomas Reese, and Milton Brightman found a novel pathway, dendrites that signaled to dendrites. While studying the mammalian olfactory bulb, they found that there were active dendrites that couple and send signals to each other. The topic was then only explored sporadically due to difficulties with techniques and technology available to further investigate dendrodendritic synapses. Investigations into this phenomenon of active dendrites has resurfaced with vigor at the start the 21st century. The study of dendrodendritic synapses in the olfactory bulb provided some early examples of ideas about neuronal organization relating to dendritic spines〔 * One spine could serve as an input-output unit * One neuron could contain multiple dendritic spines * These spines are widely spaced, indicating some independent function * Synaptic input-output events can occur without axonal stimulation 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dendrodendritic synapse」の詳細全文を読む スポンサード リンク
|