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The Skin Hyperaemic Response to Local Injection of Substance P and Capsaicin in Diabetes Mellitus
Author(s) -
Boolell M.,
Tooke J. E.
Publication year - 1990
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.1990.tb01325.x
Subject(s) - hyperaemia , medicine , capsaicin , substance p , diabetes mellitus , endocrinology , histamine , anesthesia , blood flow , neuropeptide , receptor
Recent studies have demonstrated impaired skin hyperaemia to local injury in diabetes mellitus. In order to gain insight into the mechanisms of impaired hyperaemia, dose‐response curves to intradermal substance P (25, 50, 100 pmol) and capsaicin (1.0, 2.5, 5.0 nmol) were examined before and after histamine blockade with chlorpheniramine, in 6 patients with uncomplicated Type 1 diabetes and 9 matched control subjects. Skin hyperaemia was measured indirectly as the peak laser Doppler flow in proximity to the area of hyperaemia. The response to the three doses of substance P was significantly lower in diabetic patients (0.37 ± 0.12 (± SD), 0.51 ± 0.12, 0.67 ± 0.09 V) than in control subjects (0.57 ± 0.15, 0.70 ± 0.19, 0.84 ± 0.21 V; p < 0.01). In contrast there was no significant difference in skin hyperaemia to capsaicin between diabetic patients (0.41 ± 0.07, 0.50 ± 0.09, 0.59 ± 0.09 V) and control subjects (0.41 ± 0.06, 0.52 ± 0.08, 0.63 ± 0.07 V). Following chlorpheniramine, the response to capsaicin remained unaltered (0.39 ± 0.07, 0.51 ± 0.05, 0.60 ± 0.07 in diabetic patients and 0.43 ± 0.08, 0.50 ± 0.10, 0.63 ± 0.07 V in control subjects), but there was a significant reduction in hyperaemia to substance P in both patients (20.4 ± 12.3% reduction, p < 0.05) and control subjects (20.6 ± 14.1% reduction, p < 0.05). It is suggested that impaired skin hyperaemia may represent decreased vascular reactivity to locally released substance P from peripheral nerve fibres.