Rat hemopressin is a bioactive peptide fragment derived from the hemoglobin α1 chain. Hemopressin exhibits potent vasoactive biological activity, reducing rat blood pressure over a dosage range of 0.1-10 μg/kg. This peptide is also a potent central cannabinoid (CB1) receptor antagonist conferring analgesia and pain relief or antinociception in vivo. Further studies will clarify the cellular and physiological effects of hemopressin, as well the possible products of endopeptidase activity on hemopressin. This peptide is sparingly soluble in water and the following resuspension technique is recommended. Bring the peptide to room temperature and empty the contents of the vial into a 25 ml graduated cylinder. Use 1 mL serial aliquots of sterile filtered water to dissolve any remaining peptide in the glass vial to quantitatively transfer the total amount to the cylinder. Finally, add sterile filtered water to 20 ml final volume and mix gently to dissolve fully. One milligram of hemopressin dissolved in 20 ml water provides a 45.9 μM solution. One milligram per milliliter concentrations of hemopressin may also be prepared with the use of 10% methanol in water containing 0.1% trifluoroacetic acid.
