Synergistic role of cAMP and IP3 in corticotropin-releasing hormone-induced cell shape changes in invertebrate immunocytes

Immunocytes from the mollusc galloprovincialis express corticotropin-releasing hormone (CRH) receptor subtype (CRH-R1 and CRH-R2)-like mRNAs. Using computer-assisted microscopic image analysis, we have found that exogenous CRH provokes changes in the cellular shape of immunocytes, and that this response is extracellular Ca2+-dependent. The various inhibitors of transduction signaling pathways, i.e. suramin sodium, 2',5' -dideoxyadenosine: neomycin sulfate, calphostin C, H-89, and wortmannin, completely or partially inhibit these changes. The present findings demonstrate that PKA, PKC, and PKB/Akt are involved in CRH-induced cell shape changes in immunocytes, and that the cellular effect of CRH needs the synergistic action of the two second messengers, cAMP and IP3. (C) 2000 Elsevier Science Inc. All rights reserved.