Lateral tegmental field neurons sensitive to muscular contraction: A role in pressor reflexes?

Gary A. Iwamoto, Tony G. Waldrop

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The medullary lateral tegmental field (LTF) has a major role in sympathetic nerve discharge (SND) rhythmicity, but its role in pressor reflexes generated by hindlimb muscular contraction (MC) is unknown. Therefore, two sets of experiments were performed in 17 chloralose-urethane anesthetized cats. First, responses of single LTF neurons to MC induced by L7-S1 ventral root stimulation were examined. The majority (30 of 47) of LTF neurons increased firing during MC. Most LTF neurons had a basal discharge correlated with the 2-10 Hz rhythm of SND or the cardiac cycle and responded to increases in blood pressure. Only seven neurons were inhibited by MC, most having a respiratory rhythm. Second, pressor responses to MC and to caudal hypothalamic stimulation were examined before and after bilateral LTF microinjections of a synaptic blocker (CoCl2) as well as with lidocaine. Microinjection of COCl2 or lidocaine significantly attenuating the dominant 2-10 Hz power coefficient of SND had no effect on the pressor responses to MC or caudal hypothalamic stimulation. Therefore, LTF may be important for basal rhythms in SND and may help synchronize SND during MC, but its contribution to basal rhythms is apparently not required for pressor reflexes evoked by hindlimb MC or hypothalamic stimulation.

Original languageEnglish (US)
Pages (from-to)111-120
Number of pages10
JournalBrain Research Bulletin
Volume41
Issue number2
DOIs
StatePublished - Jan 1 1996

Keywords

  • Blood pressure
  • Cat
  • Exercise
  • Hypothalamus
  • Medulla

ASJC Scopus subject areas

  • Neuroscience(all)

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