title: A sodium leak current regulates pacemaker activity of adult central pattern generator neurons in Lymnaea stagnalis.
abstract: The resting membrane potential of the pacemaker neurons is one of the essential mechanisms underlying rhythm generation. In this study, we described the biophysical properties of an uncharacterized channel (U-type channel) and investigated the role of the channel in the rhythmic activity of a respiratory pacemaker neuron and the respiratory behaviour in adult freshwater snail Lymnaea stagnalis. Our results show that the channel conducts an inward leak current carried by Na(+) (I(Leak-Na)). The I(Leak-Na) contributed to the resting membrane potential and was required for maintaining rhythmic action potential bursting activity of the identified pacemaker RPeD1 neurons. Partial knockdown of the U-type channel suppressed the aerial respiratory behaviour of the adult snail in vivo. These findings identified the Na(+) leak conductance via the U-type channel, likely a NALCN-like channel, as one of the fundamental mechanisms regulating rhythm activity of pacemaker neurons and respiratory behaviour in adult animals.
authors.affiliation: Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Tom Z
authors.initials: TZ
authors.lastname: Lu
authors.forename: Zhong-Ping
authors.initials: ZP
authors.lastname: Feng
mesh_terms: D000375:Aging / Q000187:drug effects / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002469:Cell Separation; D004560:Electricity; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005682:Gadolinium / Q000494:pharmacology; D055785:Gene Knockdown Techniques; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D008195:Lymnaea / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D012330:RNA, Double-Stranded / Q000378:metabolism; D016415:Sequence Alignment; D015222:Sodium Channels / Q000737:chemistry / Q000378:metabolism*
chemical_list: D012330:RNA, Double-Stranded; D015222:Sodium Channels; D005682:Gadolinium; D002118:Calcium