Patch-clamp recordings from cerebellar basket cell bodies and their presynaptic terminals reveal an asymmetric distribution of voltage-gated potassium channels.
Cerebellar basket cells form highly specialized inhibitory synaptic contacts with Purkinje cells, namely the pericellular basket and pinceau nerve terminal structures, wrapping around the Purkinje cell somatic and axon hillock regions. These inhibitory synaptic contacts are ideally located to control the ultimate output of the cerebellar cortex. Previous immunohistochemical studies have shown that these synaptic structures possess a very high density of the dendrotoxin (DTX)-sensitive potassium channel subunit, Kv1.2. We have taken advantage of this unique anatomical arrangement offering a high concentration of identified Kv channel subunits by combining whole-cell patch-clamp recording and fluorescence microscopy to establish a novel preparation and perform the first recordings from unambiguously identified mammalian CNS inhibitory presynaptic terminals. We report that DTX-sensitive potassium channels are present in basket cell terminals but not in the basket cell soma. This selective cellular distribution suggests that these channels play an important role in modulating cerebellar inhibitory synaptic transmission.
Southan
A P
AP
Electrophysiology Group, Department of Biochemistry, Imperial College of Science, Technology and Medicine, London SW7 2AY, United Kingdom.
Robertson
B
B
D000818:Animals; D048429:Cell Size; D004546:Elapid Venoms / Q000494:pharmacology; D004558:Electric Stimulation; D015640:Ion Channel Gating / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology*; D017729:Presynaptic Terminals / Q000737:chemistry / Q000502:physiology*; D011689:Purkinje Cells / Q000737:chemistry* / Q000166:cytology / Q000502:physiology*; D012964:Sodium / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology
D004546:Elapid Venoms; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D013779:Tetrodotoxin; C020273:dendrotoxin; D012964:Sodium; D011188:Potassium