The mechanism of intrinsic amplification of hyperpolarizations and spontaneous bursting in striatal cholinergic interneurons.
Striatal cholinergic interneurons pause their ongoing firing in response to sensory stimuli that have acquired meaning as a signal for learned behavior. In slices, these cells exhibit both spontaneous activity patterns and spontaneous pauses very similar to those seen in vivo. The mechanisms responsible for ongoing firing and spontaneous pauses were studied in striatal slices using perforated patch recordings. All hyperpolarizations, whether spontaneous or generated by current injection, were amplified and shaped by two hyperpolarization-activated currents. Hyperpolarization onsets were regeneratively amplified by a potassium current (KIR) whose activation promoted further hyperpolarization. The termination of hyperpolarizations was controlled by a time-dependent nonspecific cation current (HCN). The duration and even the sizes of spontaneous and driven hyperpolarizations and pauses in spontaneous activity in cholinergic interneurons are largely autonomous properties of the neuron, rather than reflections of characteristics of the input eliciting the response.
Wilson
Charles J
CJ
Department of Biology, University of Texas at San Antonio, 6900 North Loop, 1604 West, San Antonio, Texas 78249, USA. charles.wilson@utsa.edu
D000109:Acetylcholine / Q000378:metabolism*; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001030:Apamin / Q000494:pharmacology; D001464:Barium / Q000494:pharmacology; D002586:Cesium / Q000494:pharmacology; D003342:Corpus Striatum / Q000166:cytology* / Q000254:growth & development; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D066298:In Vitro Techniques; D007395:Interneurons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009433:Neural Inhibition / Q000187:drug effects; D018408:Patch-Clamp Techniques / Q000379:methods; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D026941:Sodium Channel Blockers / Q000494:pharmacology; D019789:Tetraethylammonium / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
D011743:Pyrimidines; D026941:Sodium Channel Blockers; C082246:ICI D2788; D002586:Cesium; D001030:Apamin; D001464:Barium; D013779:Tetrodotoxin; D019789:Tetraethylammonium; D000109:Acetylcholine