High dendritic expression of Ih in the proximity of the axon origin controls the integrative properties of nigral dopamine neurons

摘要

Key points class="unordered" style="list-style-type:disc" id="tjp6844-list-0001">The hyperpolarization‐activated cation current I h is expressed in dopamine neurons of the substantia nigra, but the subcellular distribution of the current and its role in synaptic integration remain unknown.We used cell‐attached patch recordings to determine the localization profile of I h along the somatodendritic axis of nigral dopamine neurons in slices from young rats. I h density is higher in axon‐bearing dendrites, in a membrane area close to the axon origin, than in the soma and axon‐lacking dendrites.Dual current‐clamp recordings revealed a similar contribution of I h to the waveform of single excitatory postsynaptic potentials throughout the somatodendritic domain.The I h blocker ZD 7288 increased the temporal summation in all dendrites with a comparable effect in axon‐ and non‐axon dendrites.The strategic position of I h in the proximity of the axon may influence importantly transitions between pacemaker and bursting activities and consequently the downstream release of dopamine.