Reactivity of isolated toad aortic rings to angiotension II: the role of nitric oxide

Physiological and Biochemical Vascular Reactivity Parameters of Angiotensin II and the Action of Biased Agonist TRV023

Vascular reactivity experiments using isolated aortic rings have been widely used as a model for physiological and pharmacological studies since the early sixties. Here, we suggest several parameters that the researcher should pay attention to when investigating angiotensin II in their experimental models. Angiotensin II is one of the active peptides of the renin-angiotensin system and exerts its effect through the AT1 and AT2 receptors. Some studies seek to understand the effects of angiotensin II receptors at the vascular level by using vascular reactivity experiments. However, because of the large number of variations, there are only a handful of reactivity studies that seek to use this method. Thus, the objective of this study was to standardize experimental methods with angiotensin II, through vascular reactivity protocols. For this, variables such as basal tension, concentration interval, single concentration, curve concentration response, and multiple experiments using the same aortic ring were developed using the technique of vascular reactivity in an organ bath. This is the first study that has standardized the vascular reactivity protocol. In addition, we demonstrated the effects of TRV023-biased ligand of the AT1R at vascular sites.

Different vasodilator mechanisms in intermediate- and small-sized arteries from the hindlimb vasculature of the toad Rhinella marina

In this study, myography was used to determine the effect of arterial size on nitric oxide (NO) vasodilatory mechanisms in the hindlimb vasculature of the toad Rhinella marina. Immunohistochemical analysis showed NO synthase (NOS) 1 immunoreactivity in perivascular nitrergic nerves in the iliac and sciatic arteries. Furthermore, NOS3 immunoreactivity was observed in the vascular smooth muscle of the sciatic artery, but not the endothelium. Acetylcholine (ACh) was used to facilitate intracellular Ca2+ signaling to activate vasodilatory pathways in the arteries. In the iliac artery, ACh-mediated vasodilation was abolished by blockade of the soluble guanylate cyclase pathway with the soluble guanylate cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, 10−5 M) and blockade of the prostaglandin signaling pathway with indomethacin (10−5 M). Furthermore, disruption of the endothelium had no effect on the ACh-mediated vasodilation in the iliac artery, and generic inhibition of NOS with Nω-nitro-l-arginine (3 × 10−4 M) significantly inhibited the vasodilation, indicating NO signaling. In contrast to the iliac artery, ACh-mediated vasodilation of the sciatic artery had a significant endothelium-dependent component. Interestingly, the vasodilation was not significantly affected by Nω-nitro-l-arginine, but it was significantly inhibited by the specific NOS1 inhibitor N5-(1-imino-3-butenyl)-l-ornithine (vinyl-l-NIO, 10−4 M). ODQ mostly inhibited the ACh-mediated vasodilation. In addition, indomethacin also significantly inhibited the ACh-mediated vasodilation, indicating a role for prostaglandins in the sciatic artery. This study found that the mechanisms of vasodilation in the hindlimb vasculature of R. marina vary with vessel size and that the endothelium is involved in vasodilation in the smaller sciatic artery.

Argentinean Society of Experimental Pharmacology: Brief history and main scientific contributions to the discipline

Argentina Biomedical Science has been historically strong. The development of Human and Veterinary Pharmacology in our country as a pivotal discipline has been acknowledged worldwide because of the quality of its contributions. Argentinean Society of Experimental Pharmacology (SAFE) is a non- profit association whose research fields include Experimental and Clinical Pharmacology. SAFE main goals are described as follow (a) To meet active researchers for studying concerns regarding Experimental and Clinical Pharmacology (b) To launch an initiative for development of the discipline in mainly our country and other collaborative countries worldwide (c) To spread the pharmacological know-how obtained from different research teams (d) To strengthen relations between pharmacologists (e) To facilitate the presentation and discussion of scientific papers. This current article shows the SAFE's more important scientific contribution to pharmacology through its former research scientists to the present.