Paraoxon Attenuates Vascular Smooth Muscle Contraction through Inhibiting Ca²⁺Influx in the Rabbit Thoracic Aorta

Abstract

We investigated the effect of paraoxon on vascular contractility using organ baths in thoracic aortic rings of rabbits and examined the effect of paraoxon on calcium homeostasis using a whole-cell patch-clamp technique in isolated aortic smooth muscle cells of rabbits. The findings show that administration of paraoxon (30 μM) attenuated thoracic aorta contraction induced by phenylephrine (1 μM) and/or a high K+ environment (80 mM) in both the presence and absence of thoracic aortic endothelium. This inhibitory effect of paraoxon on vasoconstrictor-induced contraction was abolished in the absence of extracellular Ca2+, or in the presence of the Ca2+ channel inhibitor, verapamil. But atropine had little effect on the inhibitory effect of paraoxon on phenylephrine-induced contraction. Paraoxon also attenuated vascular smooth muscle contraction induced by the cumulative addition of CaCl2 and attenuated an increase of intracellular Ca2+ concentration induced by K+ in vascular smooth muscle cells. Moreover, paraoxon (30 μM) inhibited significantly L-type calcium current in isolated aortic smooth muscle cells of rabbits. In conclusion, our results demonstrate that paraoxon attenuates vasoconstrictor-induced contraction through inhibiting Ca2+ influx in the rabbits thoracic aorta.

Protective effect of crocin against apoptosis induced by subchronic exposure of the rat vascular system to diazinon

“…Organophosphate (OP) insecticides are used commercially (agriculture and industries) and domestically (in homes) to control pests (Zhou et al, 2010). In addition to the toxic effects of OPs on different tissues (Zhou et al, 2010), research has reported that they have effects on the circulatory system (Guvenic Tuna et al, 2011).…”

“…Organophosphate (OP) insecticides are used commercially (agriculture and industries) and domestically (in homes) to control pests (Zhou et al, 2010). In addition to the toxic effects of OPs on different tissues (Zhou et al, 2010), research has reported that they have effects on the circulatory system (Guvenic Tuna et al, 2011). Some studies reported that acute and chronic toxicity of OPs lead to the degeneration of collagenous and elastic fibers of the vascular wall (Akimov and Kolesnichenko, 1985;Antov et al, 1984;Yavuz et al, 2005).…”

The Neuro-protective Role of Vitamin B12 in Diazinon Poisoned Male Wistar Rats: Histopathological and Biochemical Evaluation

“…Diazinon causes a serious damage to different tissues either in human and animals such as neurotoxicity, myocardial injury, cytotoxicity and other systemic dysfunctions by inhibition of acetyl cholinesterase and up regulation of its receptors due to acetylcholine accumulation [8].…”

Evaluation of Protein Ubiquitylation in Heart Tissue of Rats Exposed to Diazinon (an Organophosphate Insecticide) and Crocin (an Active Saffron Ingredient): Role of HIF-1α

“…DZN is an organophosphate insecticide widely used around the world to control insects in agriculture. Although the main mechanism of DZN toxicity is the inhibition of acetylcholinesterase (AChE) [8], however, recent studies have shown that acute and chronic toxicity of DZN induce oxidative stress leading to generation of free radicals and change in antioxidants or ROS scavenging enzymes in different tissues such as cardiovascular system [9][10][11][12]. Crocin is a carotenoid isolated from Crocus sativus L. (saffron).…”