Costa, L.V., Malpezzi, E.L.A., Berlinck, R.G.S., Rowan, E.G. and Freitas, J.C., “The Histamine-like Effects of Phallusia nigra Extracts: Evidences for Direct Activity at H1 Receptor”, Comparative Biochemistry and Physiology, 117C, 111-115 (1997).

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 na authentic standard.