Nitric Oxide Mediates the Hypertensive Response to a Modified Hemoglobin Solution (DCLHBTH) in Rats

Abstract

We investigated the effect of nitric oxide synthase inhibition with L-NAME, and of L-arginine (nitric oxide synthase substrate), on the hemodynamic response to a modified hemoglobin solution (DCLHb). Rats were given one of the following regimens (all groups hypervolemic except Control): Control-8.0 ml of donor blood (isovolemic exchange); HV-8.0 ml of donor blood; DCLHb-8.0 ml of DCLHb; L-NAME-30 mg-kg-¹ of L-NAME followed by 8.0 ml of DCLHb; or L-Arg-8.0 ml of DCLHb followed by L-arginine (600 mg-kg-¹). Mean arterial blood pressure (MABP) was continuously recorded and the change compared to baseline and expressed as M´BP M´BP was greater in the HV and DCLHb groups versus the Control and L-NAME groups; and was greater in the DCLHb group versus the HV group. M´BP was not different between the Control and L-NAME group In the L-Arg group the initial M´BP (after DCLHb) was similar to the DCLHb group; however, after L-arginine administration M´BP was not different from the Control group. This study supports a hypothesis that DCLHb effects an increase in MABP by a nitric oxide related mechanism.

Key Words:

• cGMP cyclic-guanosine monophosphate
• DCLHb α-α diaspirin cross-linked hemoglobin
• L-NAME N^G-nitro-L-arginine methyl ester
• MABP mean arterial blood pressure