Comparison of vasodilator effects of substance P in human forearm vessels of normoalbuminuric Type 1 diabetic and non-diabetic subjects.
OBJECTIVE
To compare the vasodilatory responses to substance P in human forearm vessels in Type 1 normoalbuminuric diabetic and non-diabetic subjects.


METHODS
Forearm blood flow (FBF) was measured using a plethysmography technique in 12 normoalbuminuric Type 1 diabetic subjects (six males, six females) (HbA(1c) 8.2 +/- 0.3% (mean +/- SEM)) and 12 non-diabetic healthy control subjects in response to the infusion of the vasodilators substance P (SP), acetylcholine (ACh) and nitroprusside.


RESULTS
There was no significant difference in baseline FBF between the two groups (2.80 +/- 0.29 ml/min per 100 ml forearm tissue (diabetic group) vs. 2.85 +/- 0.37 ml/min per 100 ml (non-diabetic group), P = 0.45). Infusion of SP was associated with an incremental increase in FBF in the diabetic (0.6, 2 and 6 ng/min - 6.08 +/- 1.07, 7.82 +/- 1.08 and 9.48 +/- 1.14 ml/min per 100 ml, respectively) and the non-diabetic group (0.6, 2 and 6 ng/min - 5.41 +/- 0.80, 6.93 +/- 0.96 and 9.25 +/- 1.11 ml/min per 100 ml, respectively). Similarly, an incremental rise in FBF was observed during infusion of ACh (diabetic group: 7.5, 15 and 30 microg/min - 7.14 +/- 1.22, 8.91 +/- 1.40 and 11.67 +/- 1.93 ml/min per 100 ml, respectively; non-diabetic group: 7.5, 15 and 30 microg/min - 5.87 +/- 0.81, 7.49 +/- 0.96 and 10.74 +/- 1.29 ml/min per 100 ml, respectively). When FBF was expressed as percentage change from baseline, there was no significant difference in vasodilatory responses between the two groups for SP (0.6 ng/min, P = 0.21; 2 ng/min, P = 0.19; 6 ng/min, P = 0.19) or ACh (7.5 microg/min, P = 0.20; 15 microg/min, P = 0.20; 30 microg/min, P = 0.35).


CONCLUSIONS
This study suggests that endothelium-dependent vasodilatory responses to SP (and ACh) are not impaired in Type 1 diabetic subjects with normal urinary albumin excretion.
Meeking
D R
DR
Department of Diabetes, Queen Alexandra Hospital, Portsmouth, Hampshire, UK.
Allard
S
S
Munday
J
J
Chowienczyk
P J
PJ
Shaw
K M
KM
Cummings
M H
MH
D000109:Acetylcholine / Q000008:administration & dosage / Q000494:pharmacology; D000419:Albuminuria; D001783:Blood Flow Velocity; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D009599:Nitroprusside / Q000008:administration & dosage / Q000494:pharmacology; D013373:Substance P / Q000008:administration & dosage / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*
D000109:Acetylcholine; D006442:Glycated Hemoglobin; D009599:Nitroprusside; D013373:Substance P; D014665:Vasodilator Agents