ABSTRACT. To address the role of thrombin in early embryogenesis, hirudin, a thrombin specific inhibitor was microinjected into developing zebrafish embryos to inhibit the temporal activity of thrombin during early embryonic development. We found that the fibrin forming activity is inhibited by the presence of hirudin. We also found that hirudin affects development in zebrafish embryos suggesting thrombin's role in early embryogenesis. This ability to inhibit thrombin activity in developing embryos should facilitate studies on identifying signal transduction pathways affected by thrombin during embryogenesis.

Keywords: Hirudin, thrombin, hemostasis, development, zebrafish.

Reprint requests to: Pudur Jagadeeswaran, Ph.D., Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78284-7762, phone: (210) 567-3848, fax: (210) 567-3803, e-mail: jagadeeswar@uthscsa.edu.