PACAP-38 Is a Chemorepellent and an Agonist for the Lysozyme Receptor in Tetrahymena thermophila

Authors

S. R. Mace
J. G. Dean
J. R. Murphy
J. L. Rhodes
Heather G. Kuruvilla, Cedarville UniversityFollow

Document Type

Article

Publication Date

1-18-2000

Journal Title

Journal of Comparative Physiology A

Volume

186

Issue

1

First Page

39

Last Page

43

Abstract

Pituitary adenylate cyclase activating peptide (PACAP-38) is a peptide hormone which functions in many mammalian systems, including the nervous and digestive systems. Using in vivo behavioral studies, we have found that this hormone functions as a chemorepellent in Tetrahymena thermophila with an EC₅₀ of 10 nM. Cells previously adapted to PACAP-38 were found to be adapted to lysozyme, and vice versa. Furthermore, the in vivo behavioral activity of PACAP-38 was blocked by addition of the anti-lysozyme receptor antibody, 5545. Chemorepellent activity of PACAP-38 was also inhibited by the addition of neomycin sulfate (inhibition constant K_i=0.080 μmol · l⁻¹), a competitive inhibitor of lysozyme binding to its receptor. PACAP-38 is a more potent and specific agonist for the lysozyme receptor than either intact lysozyme or CB2, a 24-amino acid fragment of lysozyme.

Keywords

Chemorepellent, PACAP-38, Tetrahymena, Chemosensory transduction, Behavioral adaptation

Recommended Citation

Mace, S. R., Dean, J. G., Murphy, J. R. , Rhodes, J. L. , & Kuruvilla, H. G. (2000). PACAP-38 is an agonist for the lysozyme receptor in Tetrahymena thermophila. Journal of Comparative Physiology A, 186 (1), 39-43.