Author + information
- Received March 19, 1990
- Revision received July 25, 1990
- Accepted August 3, 1990
- Published online February 1, 1991.
- ↵*.Address for reprints: Richard J. Katz, MD, Division of Cardiology, George Washington University, 2150 Pennsylvania Avenue NW, Washington, D.C. 20037.
Depletion of sulfhydryl groups may contribute to nitroglycerin tolerance after long-term exposure. This study was performed to assess whether methionine, an amino acid capable of augmenting sulfhydryl availability, would restore the venodilative response to sublingual nitroglycerin once tolerance had developed. The venodilative response to organic nitrates was assessed with use of the equilibration technique of forearm plethysmography. Venous volume was measured before and after sublingual administration of 0.4 mg of nitroglycerin at baseline study and after 5 g of intravenous methionine. Retesting was performed 2 h after application of a 10 mg nitroglycerin patch and compared with the response after 74 h of nitroglycerin patch exposure before and after intravenous methionine.
Methionine alone had no intrinsic venodilative action. Although the venous volume at rest was unchanged after methionine administration, the response to sublingual nitroglycerin was potentiated compared with baseline values (37 ± 15% versus 32 ± 13%, p < 0.02). During nitroglycerin patch exposure, the response to sublingual nitroglycerin was significantly attenuated at 74 h compared with the response at 2 h of exposure (16 ± 10% versus 31 ± 13%, p < 0.001). The venodilative response to sublingual nitroglycerin was restored at 74 h after methionine administration (35 ± 14% versus 16 ± 10%, p < 0.001).
Thus, methionine potentiates the venodilative effect of sublingual nitroglycerin both immediately and in the setting of nitrate tolerance.
- Received March 19, 1990.
- Revision received July 25, 1990.
- Accepted August 3, 1990.
- American College of Cardiology Foundation