Pharmacological features of the vasodilation induced by tertatolol in isolated perfused rat kidneys.

The aim of the studies summarized in the present review was to obtain a pharmacological characterization of the in vitro renal vasodilator action of tertatolol. In isolated Tyrode-perfused rat kidneys, previously constricted with norepinephrine, serotonin or BaCl2, tertatolol evokes vasodilatation. These dilator responses cannot be explained by an interaction of tertatolol with alpha- or beta-adrenoceptors, muscarinic or nicotinic receptors, opioid receptors, dopamine receptors or histamine receptors, and they occur independently of the release of prostaglandins. Since methylene blue, an inhibitor of the soluble form of guanylate cyclase, reduces the renal dilator effect of tertatolol, this action could ultimately depend, at least in part, on the production of cyclic guanosine monophosphate; in this respect, the renal effects of tertatolol and atrial natriuretic factor (ANF) are different. From experiments performed with canine renal arteries and with the perfused rat mesentery, it can be concluded that the effect of tertatolol is more pronounced at the level of the resistance vessels. The in vitro renal dilator response observed with tertatolol may help to explain the beneficial effect on the renal circulation observed in both humans and experimental animals treated with the compound.