Richet and Portier studied the immunization of dogs against attenuated toxic extracts of the sea anemone and showed that, when given secondary injections of sublethal amounts of native toxic extracts, the dogs experienced severe pruritus and insensitivity followed by death. They called this increased sensitivity to the toxins, anaphylaxis. Richet and Portier, and later Jacques and Schachter, and Uvnäs also studied the direct pruritic and histamine releasing effects of cnidarian (e.g. Physalia, Actinia, Cyanea), toxic extracts. While the anaphylactic effect, discovered by Richet and Portier, has been extended by numerous studies to provide the foundation of our current knowledge of allergic atopy and anaphylaxis, the study of the direct pruritic or histamine releasing effects of cnidarian toxins have been left largely unstudied.

The present study investigates the general mechanism whereby nematocyst venom causes the direct release of histamine from isolated mast cells. It attempts to compare this effect, histamine release, with other studies using whole tissue extracts and/or whole animals. Crude peritoneal mast cells were obtained from male Sprague-Dawley rats, washed and suspended in Locke's solution, and purified by sedimentation. To characterize the requirements for Physalia venom-induced histamine release, mast cells and nematocyst venom were incubated together in the presence or absence of calcium, at different temperatures, and with ATP depleted and ATP supplied mast cells. Following treatment the samples were assayed fluormetrically for both released histamine and released lactate dehydrogenase, a cytoplasmic enzyme marker.

Physalia venom causes the release of both histamine and lactate dehydrogenase. The release of histamine is dose-dependent and approaches 100% at high doses of venom. The dose-response curve is hyperbolic in shape. Histamine release is independent of calcium and energy, and the rate of release is optimal in the range from 10-30°C. The release of lactate dehydrogenase is concomitant with histamine release; release is also dose-dependent and is more sensitive to the venom than histamine release. ATP depletion increases the sensitivity of venom-induced lactate dehydrogenase release while having no effect on histamine release.

It is concluded that Physalia venom induces the release of both histamine and lactate dehydrogenase from isolated rat peritoneal mast cells by a cytolytic mechanism. This conclusion is based on the following observations: histamine release is neither dependent on a cellular source of energy nor calcium; histamine release is fairly temperature insensitive; and lactate dehydrogenase is released along with histamine.

LLU Discipline





Graduate School

First Advisor

David A. Hessinger

Second Advisor

Ramon Gonzalez

Third Advisor

Anthony J. Zuccarelli

Degree Name

Master of Arts (MA)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Venoms; Histamine; Portuguese Man-of-War.



Page Count

iii; 26

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives