Time course and effective sites for inhibition from midbrain periaqueductal gray of spinal dorsal horn neuronal responses to cutaneous stimuli in the cat

Earl Carstens, D. Klumpp, M. Zimmermann

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Inhibition of spinal dorsal horn neuronal responses to noxious (50 °C) skin heating by stimulation of the midbrain periaqueductal gray (PAG) was quantitatively investigated in cats anesthetized with sodium pentobarbital and nitrous oxide. Systematic variation of the interval between onset of PAG stimulation (PAGS) and onset of noxious skin heating revealed that a marked reduction of spinal unit heat-evoked discharges occured immediately upon onset of PAGS, and ceased immediately at offset of PAGS with a post-stimulation excitatory rebound. Stimulation at sites in both ventral and dorsal PAG produced inhibition, the strength of which increased sometimes in a linear manner with increasing strength of PAGS. Thresholds for the generation of descending inhibition were higher in dorsal than ventral PAG. PAGS also inhibited spinal unit responses to non-noxious skin stimulation (brushing of hairs). Descending inhibition from PAG is considered as a possible mechanism for analgesia produced by stimulation of PAG and other brainstem structures.

Original languageEnglish (US)
Pages (from-to)425-430
Number of pages6
JournalExperimental Brain Research
Volume38
Issue number4
DOIs
StatePublished - Mar 1980
Externally publishedYes

Keywords

  • Analgesia
  • Descending inhibition
  • Noxious heat
  • Periaqueductal gray
  • Spinal dorsal horn

ASJC Scopus subject areas

  • Neuroscience(all)

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