Namodenoson (2-Cl-IB-MECA) is an adenosine A3 receptor agonist.

The first infusion of 2-Cl-IB-MECA resulted in a rapid fall of the blood pressure to a value which was about 50% of the pre-administration level.?The hypotension was short-lasting.?After approximately 15 min the blood pressure started to recover and rapidly returned to stable values, which were significantly lower than the blood pressure values in the control group.?Administration of the second dose of 2-Cl-IB-MECA, at 150 min after the first infusion, did not produce any hypotension at all.?The slight increase in the mean arterial pressure during the second infusion was not specific for 2-Cl-IB-MECA[1]

Rats were randomly assigned to two treatment groups of 6 animals, which received either two subsequent intravenous infusions of 200 μg/kg 2-chloro-N^6-(3-iodobenzyl)adenosine-5′-N-methylcarboxamide (2-Cl-IB-MECA) during 15 min or two subsequent infusions of the vehicle during 15 min. 2-Cl-IB-MECA was dissolved in dimethylsulfoxide (DMSO) and diluted with a sodium chloride solution to a final 30% (v/v) DMSO solution (a total volume of 765 μl).?Fresh solutions were prepared prior to each experiment.The effect measurements were started at least 45 min prior to the first drug infusion and lasted until 4.5 h after this infusion.?Heart rate and blood pressure were recorded continuously and serial arterial blood samples were drawn for determination of plasma histamine concentrations.?2 h after the first administration the second dose of 2-Cl-IB-MECA (or vehicle) was administered[1].