Tramadol regulates the activation of human platelets via Rac but not Rho/Rho-kinase

Hiroki Iida, Takashi Onuma, Daiki Nakashima, Daisuke Mizutani, Takamitsu Hori, Kyohei Ueda, Tomoyuki Hioki, Woo Kim, Yukiko Enomoto, Tomoaki Doi, Rie Matsushima-Nishiwaki, Shinobu Yamaguchi, Junko Tachi, Kumiko Tanabe, Shinji Ogura, Toru Iwama, Osamu Kozawa^*, Haruhiko Tokuda