Realignment of signal processing within a sensory brainstem nucleus as brain temperature declines in the Syrian hamster, a hibernating species

Shin Ichi Sekizawa, John M. Horowitz, Barbara A Horwitz, Chao-Yin Chen

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Crucial for survival, the central nervous system must reliably process sensory information over all stages of a hibernation bout to ensure homeostatic regulation is maintained and well-matched to dramatically altered behavioral states. Comparing neural responses in the nucleus tractus solitarius of rats and euthermic Syrian hamsters, we tested the hypothesis that hamster neurons have adaptations sustaining signal processing while conserving energy. Using patch-clamp techniques, we classified second-order neurons in the nucleus as rapid-onset or delayed-onset spiking phenotypes based on their spiking onset to a depolarizing pulse (following a -80 mV prepulse). As temperature decreased from 33 to 15°C, the excitability of all neurons decreased. However, hamster rapid-onset spiking neurons had the highest spiking response and shortest action potential width at every temperature, while hamster delayed-onset spiking neurons had the most negative resting membrane potential. The frequency of spontaneous excitatory postsynaptic currents in both phenotypes decreased as temperature decreased, yet the amplitudes of tractus solitarius stimulation-evoked currents were greater in hamsters than in rats regardless of phenotype and temperature. Changes were significant (P < 0.05), supporting our hypothesis by showing that, as temperature falls, rapid-onset neurons contribute more to signal processing but less to energy conservation than do delayed-onset neurons.

Original languageEnglish (US)
Pages (from-to)267-282
Number of pages16
JournalJournal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
Volume198
Issue number4
DOIs
StatePublished - Apr 2012

Keywords

  • Baroreflex
  • Nucleus tractus solitarius
  • Second-order neurons
  • Whole-cell patch-clamp

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Behavioral Neuroscience

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