title: An identified central pattern-generating neuron co-ordinates sensory-motor components of respiratory behavior in Lymnaea.
abstract: Defining the attributes of individual central pattern-generating (CPG) neurons underlying various rhythmic behaviors are fundamental to our understanding of how the brain controls motor programs, such as respiration and locomotion. To this end, we have explored a simple invertebrate preparation in which the neuronal basis of respiratory rhythmogenesis can be investigated from the whole animal to a single cell level. An identified dopaminergic neuron, termed right pedal dorsal 1 (RPeD1), is a component of the CPG network which controls hypoxia-driven, aerial respiration in the fresh water snail Lymnaea stagnalis. Using intact, semi-intact and isolated brain preparations, we have discovered that in addition to its role as a respiratory CPG neuron, RPeD1 co-ordinates sensory-motor input from the pneumostome (the respiratory orifice) at the water/air interface to initiate respiratory rhythm generation. An additional, novel role of RPeD1 was also found. Specifically, direct intracellular stimulation of RPeD1 induced pneumostome openings, in the absence of motor neuronal activity. To determine further the role of RPeD1 in the respiratory behavior of intact animals, either its axon was severed or the soma selectively killed. Many components of the respiratory behavior in the intact animals were found to be perturbed following RPeD1 axotomy or 'somatomy' (soma removed). Taken together, the data presented provide a direct demonstration that RPeD1 is a multifunctional CPG neuron, which also serves many additional roles in the control of breathing behavior, ranging from co-ordination of mechanosensory input to the motor control of the respiratory orifice.
authors.affiliation: The Hotchkiss Brain Institute of Calgary, University of Calgary, Alberta T2N 4N1, Canada.
authors.forename: Zara
authors.initials: Z
authors.lastname: Haque
authors.forename: Thomas K M
authors.initials: TK
authors.lastname: Lee
authors.forename: Takuya
authors.initials: T
authors.lastname: Inoue
authors.forename: Collin
authors.initials: C
authors.lastname: Luk
authors.forename: Shabih U
authors.initials: SU
authors.lastname: Hasan
authors.forename: Ken
authors.initials: K
authors.lastname: Lukowiak
authors.forename: Naweed I
authors.initials: NI
authors.lastname: Syed
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000166:cytology*; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000187:drug effects; D018492:Dopamine Antagonists / Q000494:pharmacology; D004594:Electrophysiology / Q000379:methods; D007839:Functional Laterality / Q000187:drug effects; D017952:Ganglia, Invertebrate / Q000166:cytology; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D008124:Locomotion / Q000502:physiology*; D008195:Lymnaea / Q000502:physiology*; D009409:Nerve Crush / Q000379:methods; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D016571:Neural Networks, Computer; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods; D012143:Respiratory Physiological Phenomena; D013469:Sulpiride / Q000494:pharmacology; D013997:Time Factors
chemical_list: D018492:Dopamine Antagonists; D013469:Sulpiride; D015544:Inositol 1,4,5-Trisphosphate