Time-dependent phrenic nerve responses to carotid afferent activation: Intact vs. decerebellate rats

F. Hayashi, S. K. Coles, K. B. Bach, G. S. Mitchell, Donald R McCrimmon*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

170 Scopus citations

Abstract

The objectives were to determine 1) respiratory responses to carotid chemoreceptor inputs in anesthetized rats and 2) whether the cerebellar vermis plays a role in these responses. A carotid sinus nerve was stimulated (20 Hz) with five 2-min trains, each separated by ~3 min. During stimulation, respiratory frequency (f), peak amplitude of integrated phrenic nerve activity (∫Phr), and their product (f x ∫Phr) immediately increased. As stimulation continued, ∫Phr progressively increased to a plateau [short- term potentiation (STP)], but f and f x ∫Phr decreased [short-term depression (STD)] to a value still above control. Upon stimulus termination, ∫Phr progressively decreased but remained above control; f and f x ∫Phr transiently decreased below baseline. After the final stimulation, ∫Phr remained above control for at least 30 min [long-term facilitation (LTF)]. Repeated 5-min episodes of isocapnic hypoxia also elicited STP, STD, and LTF. Vermalectomy lowered the CO 2 -apneic threshold and eliminated LTF. In conclusion, carotid chemoreceptor activation in rats elicits STP and LTF similar to that in cats; the vermis may play a role in LTF. A new response, STD, was observed.

Original languageEnglish (US)
Pages (from-to)R811-R819
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume265
Issue number4 34-4
DOIs
StatePublished - Jan 1 1993

Keywords

  • carotid sinus nerve
  • cerebellum
  • hypoxia
  • long-term facilitation
  • phrenic nerve
  • rat
  • respiratory control
  • short-term potentiation

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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