In order to assess the influence of NMDA receptors on the response to hemorrhage, we microinjected AP5, a NMDA antagonist, 20 min prior to hemorrhage icv. Hemorrhage significantly increased plasma AVP (F(1,48)=23.73, P<0.001) while icv administration of AP5 did not change AVP plasma levels (F(2,48)=0.54, P=0.59), with no interaction between the two factors (F(2,48)=0.48, P=0.62), suggesting that the NMDA receptors were not involved in the AVP secretion in response to hemorrhage (Figure 1). The gene discussed is AVP; the disease is hemorrhage.