[Blood flow through different tissues under clonidine in rabbits (author's transl)]

The effect of i.v. administered clonidine on the blood flow through different tissues was investigated in six rabbits which had been anaesthetized with NembutalR. Six additional animals served as controls and received an equal quantity of a physiological sodium chloride solution. The blood flow was determined by means of radioactively labelled microspheres just before as well as 15, 30 and 45 min after the administration of the drug or the placebo respectively. In most of the investigated tissues a considerable decrease in blood flow was observed 15 min after the injection of clonidine, whereas no effect was to be seen after administration of sodium chloride. For the first time after 30 min, and even more after 45 min the blood flow diminished as well in the control group. The flow-decreasing effect of clonidine occured in lung, skin, choroid, the small intestine, the triceps muscle, the ciliary body, iris, and white matter, whereas the opposite reaction was observed in liver (hepatic artery), retina and the optic nerve.