Avaliação do relaxamento vascular induzido por um novo derivado pirazólico protótipo a fármaco (LQFM 021), possível inibidor de fosfodiesterase
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Data
2012-02-28
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Universidade Federal de Goiás
Resumo
The inhibition of phosphodiesterases (PDEs) increases intracellular levels of cyclic nucleotides 3 ': 5'-cyclic adenosine monophosphate (cAMP) and 3 ': 5'-cyclic guanosine monophosphate (cGMP), which has many physiological and biochemical effects, especially in cardiovascular system. The objective of this study was to analyze the pharmacological effects of a new compound derived from pyrazole, LQFM 021, which was indicated by molecular modeling studies as a possible inhibitor of PDE-3. For this purpose, aortas were isolated of rats and mounted in organ baths for isometric tension recording of the relaxing effect of LQFM 021, in preparations pre-contracted with phenylephrine. We analyzed the involvement of the vascular endothelium, soluble guanylate cyclase (sGC) and adenylate cyclase (AC), the role of K+ channels and Ca2+, besides the contribution of Ca2+ uptake by the sarcoplasmic reticulum. As a result, was demonstrated that the LQFM 021 induces vascular relaxation (Emax: 54.9 ± 6.0%), being this relaxation potentiated by endothelium (Emax: 88.1 ± 2.1%). The inhibition of AC with MDL-12.330A (10 μM) or of the sGC with ODQ (1 μM) reduced the relaxation of 88.1 ± 2.1%, to 48.35 ± 3.01% and 19.95 ± 2.32%, respectively. The pre-contraction with KCl 45 mM or treatment of preparations with TEA (5 mM), reduced almost completely the relaxing effect of the compound. Inhibition of Ca2+ / ATPase reticular with CPA (10 mM) reduced the relaxation stimulated by 021 LQFM approximately 66.5%. Concentration-response curve contractile induced by phenylephrine (0.1 nM to 1 μM) or by CaCl2 (0-3 mM, zero-calcium + phenylephrine) were reduced by pretreatment of preparations with LQFM 021 (EC50). In conclusion, this study showed that the new synthetic derivative of pyrazole LQFM 021 is a potential inhibitor of PDE-3 and has vasorelaxant activity. The endothelium potentiates the relaxation stimulated by the compound. The route of sGC and AC are involved in the mechanism of action of LQFM 021. Was also evidenced by participation from sarcoplasmatic reticulum, well as the flow of K+ and Ca2+ through the cell membrane.
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Fosfodiesterases , relaxamento , aorta , AMPc , GMPc , phosphodiesterase , relaxation , aortic , cAMP , cGMP
Citação
MARTINS, Daniella Ramos. Synthesis, vasodilator activity and toxicity of new derivative pirazólico (LQFM 021), a possible inhibitor of phosphodiesterase. 2012. 64 f. Dissertação (Mestrado em Ciências da Saúde - Farmácia) - Universidade Federal de Goiás, Goiânia, 2012.