This histamine-like effects of Phallusia nigra extract: evidences for direct activity at H1 receptors

L.V. Costa, E.L.A. Malpezzi, R.G.S. Berlinck, E.G. Rowan, J.C. deFreitas

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The methanol extract (mol. wt lower than 3,000 Da) of the sea squirt Phallusia nigra has stimulatory activity on guinea-pig ileum preparations. This effect was inhibited by cyproheptadine and mepyramine, but not by atropine. Mepyramine antagonized competitively the extract activity with a pA2 of 10.09 ± 1.12, suggesting a direct activity on H1 histamine receptors. The extract was also assayed on guinea-pig right atria, however, only a mild increase in spontaneous contractions was observed compared to histamine, showing that the extract was a rather poor activator of cardiac H2 receptors. Histamine was not detected upon TLC analysis of the extract by comparison with an authentic standard.
Original languageEnglish
Pages (from-to)111-115
Number of pages4
JournalComparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology
Volume117
Issue number1
DOIs
Publication statusPublished - May 1997

Keywords

  • Phallusia nigra
  • tunicates
  • histamine agonist
  • histamine receptors
  • mepyramine
  • competitive antagonism
  • guinea pig ileum
  • guinea pig right atria

Fingerprint Dive into the research topics of 'This histamine-like effects of Phallusia nigra extract: evidences for direct activity at H1 receptors'. Together they form a unique fingerprint.

  • Cite this