title: Activation of β-noradrenergic receptors enhances rhythmic bursting in mouse olfactory bulb external tufted cells.
abstract: The main olfactory bulb (MOB) receives a rich noradrenergic innervation from the nucleus locus coeruleus. Despite the well-documented role of norepinephrine and β-adrenergic receptors in neonatal odor preference learning, identified cellular physiological actions of β-receptors in the MOB have remained elusive. β-Receptors are expressed at relatively high levels in the MOB glomeruli, the location of external tufted (ET) cells that exert an excitatory drive on mitral and other cell types. The present study investigated the effects of β-receptor activation on the excitability of ET cells with patch-clamp electrophysiology in mature mouse MOB slices. Isoproterenol and selective β2-, but not β1-, receptor agonists were found to enhance two key intrinsic currents involved in ET burst initiation: persistent sodium (INaP) and hyperpolarization-activated inward (Ih) currents. Together, the positive modulation of these currents increased the frequency and strength of ET cell rhythmic bursting. Rodent sniff frequency and locus coeruleus neuronal firing increase in response to novel stimuli or environments. The increase in ET excitability by β-receptor activation may better enable ET cell rhythmic bursting, and hence glomerular network activity, to pace faster sniff rates during heightened norepinephrine release associated with arousal.
authors.affiliation: Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee fzhou4@uthsc.edu.
authors.forename: Fu-Wen
authors.identifier: 0000-0002-3500-666X
authors.initials: FW
authors.lastname: Zhou
authors.affiliation: Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Dong
authors.affiliation: Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Matthew
authors.initials: M
authors.lastname: Ennis
mesh_terms: D018663:Adrenergic Agents / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D055592:Biophysical Phenomena / Q000187:drug effects / Q000502:physiology; D002316:Cardiotonic Agents / Q000494:pharmacology; D004558:Electric Stimulation; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D009830:Olfactory Bulb / Q000166:cytology*; D018408:Patch-Clamp Techniques; D010507:Periodicity; D011743:Pyrimidines / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
chemical_list: D018663:Adrenergic Agents; D002316:Cardiotonic Agents; D018377:Neurotransmitter Agents; D011743:Pyrimidines; D011943:Receptors, Adrenergic, beta; C082246:ICI D2788; D009638:Norepinephrine
keywords: bursting; external tufted cells; hyperpolarization-activated cation current; isoproterenol; persistent sodium current