The vasodilatory effect of the antidiabetic drug linagliptin via inhibition of Rho-associated protein kinase in aortic smooth muscle

Abstract

AimsThe vasodilatory effects of the anti-diabetic drug, linagliptin in phenylephrine-precontracted aortic rings were investigated. Materials and methodsMale New Zealand White rabbits were used in the experiment and its arterial tone was measured by using myogragh system. Key findingsLinagliptin induced vasodilation in a concentration-dependent manner. The vasodilatory effect of linagliptin was not affected by the absence of the endothelium, or by pretreatment with a nitric oxide synthase inhibitor (L-NAME) or a small-conductance Ca2+-activated K+ channel inhibitor (apamin). Moreover, application of the adenylyl cyclase inhibitor SQ22536, protein kinase A (PKA) inhibitor KT5720, guanylyl cyclase inhibitor ODQ, or protein kinase G (PKG) inhibitor KT5823 did not alter the vasodilatory effect of linagliptin. However, inhibition of Rho-associated protein kinase by Y-27632 significantly attenuated linagliptin-induced vasodilation. Ion channel involvement in the vasodilatory effect of linagliptin was also investigated. Pretreatment with the vascular K+ channel inhibitors glibenclamide (ATP-sensitive K+ channels), Ba2+ (inwardly rectifying K+ channels), 4-AP (voltage-dependent K+ channels), and paxilline (large conductance Ca2+-activated K+ channels) did not affect linagliptin-induced vasodilation. Furthermore, the L-type Ca2+ channel inhibitor, nifedipine, and the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) pump inhibitor, thapsigargin, did not change the vasodilatory effect of linagliptin. Significance: We suggests that linagliptin-induced vasodilation was mediated by the inhibition of Rho-associated kinase, but not with the endothelium, cAMP-PKA or cGMP-PKG-dependent signaling pathways, K+ channels, Ca2+ influx, or SERCA pump.