title: Hyperpolarization-Activated Currents and Subthreshold Resonance in Granule Cells of the Olfactory Bulb.
abstract: An important contribution to neural circuit oscillatory dynamics is the ongoing activation and inactivation of hyperpolarization-activated currents (Ih). Network synchrony dynamics play an important role in the initial processing of odor signals by the main olfactory bulb (MOB) and accessory olfactory bulb (AOB). In the mouse olfactory bulb, we show thatIhis present in granule cells (GCs), the most prominent inhibitory neuron in the olfactory bulb, and thatIhunderlies subthreshold resonance in GCs. In accord with the properties ofIh, the currents exhibited sensitivity to changes in extracellular K+concentration and ZD7288 (4-ethylphenylamino-1,2-dimethyl-6-methylaminopyrimidin chloride), a blocker ofIh. ZD7288 also caused GCs to hyperpolarize and increase their input resistance, suggesting thatIhis active at rest in GCs. The inclusion of cAMP in the intracellular solution shifted the activation ofIhto less negative potentials in the MOB, but not in the AOB, suggesting that channels with different subunit composition mediateIhin these regions. Furthermore, we show that mature GCs exhibitIh-dependent subthreshold resonance in the theta frequency range (4-12 Hz). Another inhibitory subtype in the MOB, the periglomerular cells, exhibitedIh-dependent subthreshold resonance in the delta range (1-4 Hz), while principal neurons, the mitral cells, do not exhibitIh-dependent subthreshold resonance. Importantly,Ihsize, as well as the strength and frequency of resonance in GCs, exhibited a postnatal developmental progression, suggesting that this development ofIhin GCs may differentially contribute to their integration of sensory input and contribution to oscillatory circuit dynamics.
authors.affiliation: Department of Biology, University of Maryland , College Park, Maryland 20742.
authors.forename: Ruilong
authors.initials: R
authors.lastname: Hu
authors.affiliation: Neurobiology Course, Marine Biology Laboratory , Woods Hole, Massachusetts 02543.
authors.forename: Katie A
authors.initials: KA
authors.lastname: Ferguson
authors.affiliation: Neurobiology Course, Marine Biology Laboratory , Woods Hole, Massachusetts 02543.
authors.forename: Christina B
authors.identifier: 0000-0003-2093-7223
authors.initials: CB
authors.lastname: Whiteus
authors.affiliation: Neurobiology Course, Marine Biology Laboratory , Woods Hole, Massachusetts 02543.
authors.forename: Dimphna H
authors.initials: DH
authors.lastname: Meijer
authors.affiliation: Department of Biology, University of Maryland , College Park, Maryland 20742.
authors.forename: Ricardo C
authors.identifier: 0000-0001-8728-3063
authors.initials: RC
authors.lastname: Araneda
mesh_terms: D000818:Animals; D002414:Cations, Monovalent / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D018274:Electroporation; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D008810:Mice, Inbred C57BL; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000494:pharmacology; D009830:Olfactory Bulb / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D013826:Theta Rhythm; D046509:Tissue Culture Techniques
chemical_list: D002414:Cations, Monovalent; D018377:Neurotransmitter Agents; D011743:Pyrimidines; C082246:ICI D2788; D049452:Green Fluorescent Proteins; D000242:Cyclic AMP; D011188:Potassium
keywords: HCN; granule cell; neurogenesis; olfactory bulb; resonance 