Influence of morphine on the activity of low-threshold visceral mechanoreceptors in cats with acute pericarditis

Agnieszka Bałkowiec, Krzysztof Kukuła, Paweł Szulczyk

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The purpose of this investigation was to test whether morphine (morphinum hydrochloricum) applied to the receptive field of the thoracic visceral afferent fibres modifies their activity. Experiments were performed on chloralose-anaesthetised cats, paralysed and artificially ventilated, in a state of pericarditis that was induced by intrapericardial injection of λ-carrageenan and kaolin. Resulting acute inflammation was proven histopathologically and documented electrocardiographically. Single afferent fibres with receptive fields in thoracic viscera were dissected from thoracic sympathetic chain (19 fibres), as well as the vagus nerve (9 fibres). All tested fibres transmitted sensory information from the low-threshold mechanoreceptors. As a final result, it was found that morphine (0.001-1.0 mg/ml) when applied locally activates, depending on the dose, afferent fibres as follows: 12 sympathetic afferents (out of 12 tested), and 7 vagal afferents (out of 9 tested). In examining the specificity of morphine action, the preliminary local application of naloxone (1.0 mg/ml) just before morphine, blocked all excitatory responses. The excitatory response was present whether the receptive field was located in the inflammatory area, or outside it, in group III or IV fibres.

Original languageEnglish (US)
Pages (from-to)251-259
Number of pages9
JournalPain
Volume59
Issue number2
DOIs
StatePublished - Nov 1994

Keywords

  • Mechanoreceptor
  • Morphine
  • Naloxone
  • Pericarditis
  • Sympathetic afferent
  • Vagal afferent

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Anesthesiology and Pain Medicine

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