INFLUENCE AND INTERFERENCE OF ISOSORBIDE DINITRATE AND FOOD-INTAKE ONSUPERIOR MESENTERIC-ARTERY IMPEDANCE IN HUMANS

The influence of isosorbide dinitrate (ISDN) and food ingestion on sup erior mesenteric artery impedance was investigated in 24 healthy volun teers (age 40 +/- 2.7 years). Superior mesenteric artery circulation w as assessed by duplex ultrasound. Pulsatility index (PI) was considere d as a parameter of vascular resistance and was calculated as the peak -to-peak amplitude of the waveform divided by the mean amplitude. The subjects were randomly allocated to four groups (ISDN, meal, ISDN + me al, meal + ISDN). PI measurements were performed in resting and fastin g conditions and serially for 1 h after sublingual 5 mg ISDN, ingestio n of a 300-kcal, 300-ml mixed liquid meal; sublingual 5 mg ISDN follow ed 10 min later by the test meal; and ingestion of the test meal follo wed 5 min later by sublingual 5 mg ISDN. Five minutes after 5 mg subli ngual ISDN, PI had increased from 6.8 to 12.4, while after intake of a meal PI had decreased from 7.6 to 4.9. Separate effects of 5 mg ISDN and meal intake lasted for at least 1 h. The reflex vasoconstrictive e ffect of 5 mg ISDN on the superior mesenteric artery circulation was c ounterbalanced by ingestion of a meal in healthy volunteers.