Mapping the cellular electrophysiology of rat sympathetic preganglionic neurones to their roles in cardiorespiratory reflex integration: A whole cell recording study in situ

Alexey O. Stalbovskiy, Linford J B Briant, Julian F R Paton, Anthony E. Pickering*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

11 Citations (Scopus)
255 Downloads (Pure)

Abstract

Sympathetic preganglionic neurones (SPNs) convey sympathetic activity flowing from the CNS to the periphery to reach the target organs. Although previous in vivo and in vitro cell recording studies have explored their electrophysiological characteristics, it has not been possible to relate these characteristics to their roles in cardiorespiratory reflex integration. We used the working heart-brainstem preparation to make whole cell patch clamp recordings from T3-4 SPNs (n = 98). These SPNs were classified by their distinct responses to activation of the peripheral chemoreflex, diving response and arterial baroreflex, allowing the discrimination of muscle vasoconstrictor-like (MVClike, 39%) from cutaneous vasoconstrictor-like (CVClike, 28%) SPNs. The MVClike SPNs have higher baseline firing frequencies (2.52 ± 0.33 Hz vs. CVClike 1.34 ± 0.17 Hz, P = 0.007). The CVClike have longer after-hyperpolarisations (314 ± 36 ms vs. MVClike 191 ± 13 ms, P < 0.001) and lower input resistance (346 ± 49 MΩ vs. MVClike 496 ± 41 MΩ, P < 0.05). MVClike firing was respiratory-modulated with peak discharge in the late inspiratory/early expiratory phase and this activity was generated by both a tonic and respiratory-modulated barrage of synaptic events that were blocked by intrathecal kynurenate. In contrast, the activity of CVClike SPNs was underpinned by rhythmical membrane potential oscillations suggestive of gap junctional coupling. Thus, we have related the intrinsic electrophysiological properties of two classes of SPNs in situ to their roles in cardiorespiratory reflex integration and have shown that they deploy different cellular mechanisms that are likely to influence how they integrate and shape the distinctive sympathetic outputs. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Original languageEnglish
Pages (from-to)2215-2236
Number of pages22
JournalJournal of Physiology
Volume592
Issue number10
Early online date24 Mar 2014
DOIs
Publication statusPublished - 15 May 2014

Bibliographical note

© 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

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