Secondhand smoke exposure alters K+ channel function and intrinsic cell excitability in a subset of second-order airway neurons in the nucleus tractus solitarius of young guinea pigs

Shin Ichi Sekizawa, Jesse P. Joad, Kent E Pinkerton, Ann C. Bonham

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Extended exposure to secondhand smoke (SHS) in infants and young children increases the incidence of cough, wheeze, airway hyper-reactivity and the prevalence and earlier onset of asthma. The adverse effects may result from environmentally-induced plasticity in the neural network regulating cough and airway function. Using whole-cell patch-clamp recordings in brainstem slices containing anatomically identified second-order lung afferent neurons in the nucleus tractus solitarius (NTS), we determined the effects of extended SHS exposure in young guinea pigs for a duration equivalent to human childhood on the intrinsic excitability of NTS neurons. SHS exposure resulted in marked decreases in the intrinsic excitability of a subset of lung afferent second-order NTS neurons. The neurons exhibited a decreased spiking capacity, prolonged action potential duration, reduced afterhyperpolarization, decrease in peak and steady-state outward currents, and membrane depolarization. SHS exposure effects were mimicked by low concentrations of the K+ channel blockers 4-aminopyridine and/or tetraethyl ammonium. The data suggest that SHS exposure downregulates K+ channel function in a subset of NTS neurons, resulting in reduced cell excitability. The changes may help to explain the exaggerated neural reflex responses in children exposed to SHS.

Original languageEnglish (US)
Pages (from-to)673-684
Number of pages12
JournalEuropean Journal of Neuroscience
Volume31
Issue number4
DOIs
StatePublished - Feb 2010

Keywords

  • Airway afferent fibers
  • Environmental air pollutants
  • Intrinsic cell excitability
  • Ion channels
  • K currents
  • Postsynaptic neurons

ASJC Scopus subject areas

  • Neuroscience(all)

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