scholarly journals Endothelin in health and disease

2004 ◽  
Vol 4 (3) ◽  
pp. 31-34 ◽  
Author(s):  
Emina Nakaš-Ićindić ◽  
Asija Začiragić ◽  
Almira Hadžović ◽  
Nešina Avdagić

Endothelin is a recently discovered peptide composed of 21 amino acids. There are three endothelin isomers: endothelin -1 (ET-1), endothelin -2 (ET-2) and endothelin - 3 (ET-3). In humans and animals levels of ET-1, ET-2, ET-3 and big endothelin in blood range from 0,3 to 3 pg/ml. ET-1, ET-2 and ET-3 act by binding to receptors. Two main types of the receptors for endothelins exist and they are referred to as A and B type receptors. Different factors can stimulate or inhibit production of endothelin by endothelial cells. Mechanical stimulation of endothehum, thrombin, calcium ions, epinephrine, angiotensin II, vasopressin, dopamine, cytokines, growth factors stimulate the production of endothelin whereas nitric oxide, cyclic guanosine monophosphate, atrial natriuretic peptide, prostacyclin, bradykinin inhibit its production. Endothelins have different physiological roles in human body but at the same time their actions are involved in the pathogenesis of many diseases.The aim of this review was to present some of, so far, the best studied physiological roles of endothelin and to summarize evidence supporting the potential role of ET in the pathogenesis of certain diseases.

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammad Hafiz Abdul Rahim ◽  
Zainul Amiruddin Zakaria ◽  
Mohd Hijaz Mohd Sani ◽  
Maizatul Hasyima Omar ◽  
Yusnita Yakob ◽  
...  

The objectives of the present study were to determine the mechanisms of antinociceptive effect of methanol extract ofClinacanthus nutans(Acanthaceae) leaves (MECN) using various animal nociceptive models. The antinociceptive activity of orally administered 10% DMSO, 100 mg/kg acetylsalicylic acid (ASA), 5 mg/kg morphine, or MECN (100, 250, and 500 mg/kg) was determined using the acetic acid-induced abdominal constriction (ACT), formalin-induced paw licking (FT), and hot plate tests (HPT). The role of opioid and nitric oxide/cyclic guanosine monophosphate (NO/cGMP) systems was also investigated. The results showed that MECN produced a significant (p<0.05) antinociceptive response in all nociceptive models with the recordedED50value of 279.3 mg/kg for the ACT, while, for the early and late phases of the FT, the value was >500 mg/kg or 227.7 mg/kg, respectively. This antinociceptive activity was fully antagonized by naloxone (a nonselective opioid antagonist) but was partially reversed byL-arginine (L-arg; a nitric oxide [NO] precursor), Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME; an NO synthase inhibitor), or their combinations thereof. In contrast, 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ; a soluble guanylyl cyclase inhibitor) enhanced the extract’s antinociception. UHPLC analysis revealed the presence of several flavonoid-based compounds with antinociceptive action. In conclusion, MECN exerted the peripherally and centrally mediated antinociceptive activity via the modulation of the opioid/NO-mediated, but cGMP-independent, systems.


2011 ◽  
Vol 286 (12) ◽  
pp. 10712-10724 ◽  
Author(s):  
Esperanza Jiménez ◽  
Francisco Zafra ◽  
Raquel Pérez-Sen ◽  
Esmerilda G. Delicado ◽  
Maria Teresa Miras-Portugal ◽  
...  

The sodium- and chloride-coupled glycine neurotransmitter transporters (GLYTs) control the availability of glycine at glycine-mediated synapses. The mainly glial GLYT1 is the key regulator of the glycine levels in glycinergic and glutamatergic pathways, whereas the neuronal GLYT2 is involved in the recycling of synaptic glycine from the inhibitory synaptic cleft. In this study, we report that stimulation of P2Y purinergic receptors with 2-methylthioadenosine 5′-diphosphate in rat brainstem/spinal cord primary neuronal cultures and adult rat synaptosomes leads to the inhibition of GLYT2 and the stimulation of GLYT1 by a paracrine regulation. These effects are mainly mediated by the ADP-preferring subtypes P2Y1 and P2Y13 because the effects are partially reversed by the specific antagonists N6-methyl-2′-deoxyadenosine-3′,5′-bisphosphate and pyridoxal-5′-phosphate-6-azo(2-chloro-5-nitrophenyl)-2,4-disulfonate and are totally blocked by suramin. P2Y12 receptor is additionally involved in GLYT1 stimulation. Using pharmacological approaches and siRNA-mediated protein knockdown methodology, we elucidate the molecular mechanisms of GLYT regulation. Modulation takes place through a signaling cascade involving phospholipase C activation, inositol 1,4,5-trisphosphate production, intracellular Ca2+ mobilization, protein kinase C stimulation, nitric oxide formation, cyclic guanosine monophosphate production, and protein kinase G-I (PKG-I) activation. GLYT1 and GLYT2 are differentially sensitive to NO/cGMP/PKG-I both in brain-derived preparations and in heterologous systems expressing the recombinant transporters and P2Y1 receptor. Sensitivity to 2-methylthioadenosine 5′-diphosphate by GLYT1 and GLYT2 was abolished by small interfering RNA (siRNA)-mediated knockdown of nitric-oxide synthase. Our data may help define the role of GLYTs in nociception and pain sensitization.


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