Effect of group I metabotropic glutamate receptor antagonist on cardiovascular action of norepinephrine in experimental diabetes mellitus

Aim: The aim of the study was to assess the effect of group I metabotropic glutamate receptor (mGluR-1) antagonist (AIDA) on the action of norepinephrine (NA) in the cardiovascular system of diabetic rats.
Material and methods: We carried out all experiments in groups: without diabetes mellitus (DM) and with 1-month streptozotocin DM (STZ – 65 mg/kg i.v.). We used the following methods: direct measurement of arterial blood pressure and function of isolated heart by modified Langendorff method.
Results: AIDA did not influence arterial blood pressure in either studied group. Blockade of mGluR-1 with AIDA enhanced the hypertensive effect of NA in intake rats. AIDA did not change the hypertensive effect of NA in diabetic rats. Infusion of AIDA (0.001, 0.01, 0.1 µM) evoked only negative chronotropic action on isolated heart from rats without DM. AIDA diminished amplitude and heart rate, and increased coronary outflow of isolated heart from diabetic rats. Blockade of mGluR-1 with AIDA modified the cardiovascular action of NA in both studied groups. DM changed direct of the interaction of AIDA and NA.
Conclusions: mGluR-1 antagonist (AIDA) influences the heart from rats without DM and with DM (the effect is bigger than in the group without DM). Blockade of mGluR-1 with AIDA changes the cardiovascular effect of NA, mainly in DM.