Impaired beta-adrenoceptor mediated venodilation in patients with diabetes mellitus

Abstract

Aims: We investigated whether venoconstriction by alpha-adrenoceptor stimulation, and venodilation by beta-adrenoceptor stimulation and nitroglycerin are altered in patients with diabetes mellitus (DM).

Methods: Eight male patients with non insulin-dependent DM and eight age-matched control subjects were included. The patients had neither hypertension nor hyperlipidaemia. Noradrenaline (1 to 512 ng min-1 ), isoprenaline (1 to 256 ng min-1 ) and nitroglycerin (0.5 to 128 ng min-1 ) were infused into a dorsal hand vein and its diameter was measured using a linear variable differential transformer.

Results: The venoconstricting response to noradrenaline and the venodilating response to nitroglycerin in DM patients were similar to those in control subjects, while the venodilation by isoprenaline was significantly (P<0.05) smaller in DM patients than in control subjects at the dose of 32 ng min-1 or more [32 ng min-1: 11.5% vs 29.8% (DM vs control subjects), 64 ng min-1: 19.0% vs 40.1%, 128 ng min-1: 25.2% vs 49.0%, 256 ng min-1: 34.3% vs 56.7%].

Conclusions: These data suggested that venoconstriction by alpha-adrenoceptor stimulation and venodilation by nitroglycerin are not altered, whereas venodilation by beta-adrenoceptor stimulation might be impaired in patients with DM.

Figure 1

Dose-response curves of the venoconstricting effect of noradrenaline (a) and those of the venodilating effect of isoprenaline (b) and nitroglycerin (c) in eight DM (•) and eight control subjects (○) (mean±s.d.). *P<0.05 vs control subjects.