[The effect of cyclic nucleotides on the membrane potential of intact endothelium of isolated rabbit aorta].

The influence of intracellular cyclic nucleotides concentration increase on the membrane potential of intact endothelium of isolated rabbit aorta has been investigated. Both applications of bucladesine, an adenosine 3',5'-cyclic monophosphate (cAMP) membrane permeable analogue, and phoshophodiesterase blockers 3-isobutyl-1-methylxanthine (IBMX) and theophylline depolarized endothelial membrane. IBMX-induced depolarization was significantly smaller then theophylline-induced depolarization. It could be explained by the existence of IBMX-insensitive phosphodiesterases. Non-selective protein kinase blocker H-7 did not affect on the both IBMX-stimulated and non-stimulated membrane potential of aortic endothelium. It has been shown that the IBMX-induced depolarization and ATP-induced depolarization correlate with high correlation coefficient.