Endothelium‐derived dopamine modulates EFS‐induced contractions of human umbilical vessels

Abstract

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The basal release of endothelium-derived catecholamines regulates the contractions of Chelonoidis carbonaria aorta caused by electrical-field stimulation

“…Furthermore, the EFS-induced contractions were also blocked by D2-like receptor antagonists, indicating that release of dopamine plays a major role on this phenomenon. The contractions induced by EFS in human umbilical artery and vein are also blocked by D 2 -like receptor antagonists, but not affected by the D 1 -receptor antagonist SCH-23390 ( Britto-Junior et al, 2020b ). The inhibition of EFS-induced contractions by the D 2 -like receptor antagonist haloperidol reveals an important modulatory role of the endothelium-derived dopamine, acting as a vasoconstrictor through the D2-like receptors.…”

“…The results presented here clearly demonstrate, for the first time in the tortoise, that Chelonoidis carbonaria aortae have a basal release of dopamine, noradrenaline and adrenaline, as identified by tandem mass spectrometry, and the amount released is significantly reduced by endothelium-removal. Basal release of endothelium-derived catecholamines also occur in human umbilical vessels ( Britto-Júnior et al, 2020b ).…”

“…Since immunohistochemistry failed to identify nerve terminals in Chelonoidis carbonaria aortae ( Campos et al, 2020 ), the results indicate a non-neuronal source of catecholamine synthesis. Interestingly, the enzyme tyrosine hydroxylase, responsible for catalyzing the conversion of L-tyrosine to L-DOPA, was identified only in the endothelial cells from Chelonoidis carbonaria aorta ( Campos et al, 2020 ) and from both human umbilical artery and human umbilical vein ( Britto-Junior et al, 2020b ). The inhibition by phentolamine of EFS-induced contractions in both tortoise ( Campos et al, 2020 ) and umbilical cord vessels ( Britto-Júnior et al, 2020a ) was observed only at high concentrations of this adrenoceptor antagonist, suggesting that it may be acting on a different population of receptors.…”

“…The inhibition by phentolamine of EFS-induced contractions in both tortoise ( Campos et al, 2020 ) and umbilical cord vessels ( Britto-Júnior et al, 2020a ) was observed only at high concentrations of this adrenoceptor antagonist, suggesting that it may be acting on a different population of receptors. In addition, a basal endothelium-derived dopamine release was identified by tandem mass spectrometry in human umbilical cord vessels and use of the dopamine D2-like receptor antagonist haloperidol reduced the EFS-induced contraction in human umbilical cord artery and vein ( Britto-Junior et al, 2020b ).…”

Relaxation of thoracic aorta and pulmonary artery rings of marmosets (Callithrix spp.) by endothelium-derived 6-nitrodopamine

“…In pre-contracted human umbilical vessels ( 4 ) and in Chelonoidis carbonarius aortic rings ( 5 ), the relaxations induced by 6-ND were similar to those induced by the dopamine D 2 -like receptor antagonist haloperidol, since they were not affected by pre-incubation with L-NAME but strongly reduced in endothelium-denuded rings. Dopamine is released by cultured endothelial cells ( 23 ), human umbilical cord arteries and vein ( 24 ), and Chelonoidis carbonaria aortic rings ( 25 ). Indeed, immunohistochemistry for tyrosine hydroxylase of both Crotalus durissus terrificus and Bothrops jararaca aortae revealed that this enzyme is present in endothelial cells ( 26 ).…”