Evidence for a capsaicin-sensitive vasomotor mechanism in the ventral medullary chemosensitive area of the cat

G. Jancsó, G. Such

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

1. The effects of capsaicin applied to the exposed ventral surface of the medulla were studied on the mean arterial blood pressure, heart rate, respiration and sympathetic efferent nerve activity in chloralose-urethane-anaesthetized cats. 2. The application of capsaicin produced a marked increase in the mean arterial blood pressure and sympathetic nerve activity, but not in the heart rate. The "intermediate area" proved to be the most sensitive to capsaicin. Pressor responses could be elicited repeatedly; tachyphylaxis was not noted provided a time interval 30 min elapsed between consecutive applications. 3. Repeated applications of capsaicin at intervals of less than 30 min led to tachyphylaxis. However, pressor responses evoked by either topical application of glutamate or pentamethylene-tetrazole or bilateral carotid occlusion could invariably be demonstrated during this period of tachyphylaxis. 4. Histological studies revealed the existence of a higherto unrecognized termination of capsaicin-sensitive nerve endings within the ventral medullary chemosensitive area of the cat. 5. The results provide both functional and morphological evidence for the presence of a capsaicin-sensitive vasomotor mechanism in the ventral medullary chemosensitive area of the cat. It is suggested that the pressor effects of capsaicin applied to the ventral medullary chemosensitive area may be mediated by an activation of capsaicinsensitive primary sensory afferents terminating in this area. Accordingly, capsaicin-sensitive neuronal mechanisms located in the ventral medullary chemosensitive area may play an important role in the central nervous regulation of blood pressure.

Original languageEnglish
Pages (from-to)56-62
Number of pages7
JournalNaunyn-Schmiedebergs Archives of Pharmacology
Volume329
Issue number1
DOIs
Publication statusPublished - Mar 1 1985

Keywords

  • Blood pressure regulation
  • Capsaicin
  • Ventral medullary chemosensitive area

ASJC Scopus subject areas

  • Pharmacology

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