Dopamine induces inhibitory effects on the circular muscle contractility of mouse distal colon via D1- and D2-like receptors
J. physiol. biochem
; 73(3): 395-404, ago. 2017. graf, ilus, tab
Artigo
em Inglês
| IBECS
| ID: ibc-178891
Biblioteca responsável:
ES1.1
Localização: BNCS
ABSTRACT
Dopamine (DA) acts as gut motility modulator, via D1- and D2-like receptors, but its effective role is far from being clear. Since alterations of the dopaminergic system could lead to gastrointestinal dysfunctions, a characterization of the enteric dopaminergic system is mandatory. In this study, we investigated the role of DA and D1- and D2-like receptors in the contractility of the circular muscle of mouse distal colon by organ-bath technique. DA caused relaxation in carbachol-precontracted circular muscle strips, sensitive to domperidone, D2-like receptor antagonist, and mimicked by bromocriptine, D2-like receptor agonist. 7-Chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH-23390), D1-like receptor antagonist, neural toxins, L-NAME (nitric oxide (NO) synthase inhibitor), 2'-deoxy-N6-methyl adenosine 3',5'-diphosphate diammonium salt (MRS 2179), purinergic P2Y1 antagonist, or adrenergic antagonists were ineffective. DA also reduced the amplitude of neurally evoked cholinergic contractions. The effect was mimicked by (±)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrobromide (SKF-38393), D1-like receptor agonist and antagonized by SCH-23390, MRS 2179, or L-NAME. Western blotting analysis determined the expression of DA receptor proteins in mouse distal colon. Notably, SCH-23390 per se induced an increase in amplitude of spontaneous and neurally evoked cholinergic contractions, unaffected by neural blockers, L-NAME, MRS 2179, muscarinic, adrenergic, or D2-like receptor antagonists. Indeed, SCH-23390-induced effects were antagonized by an adenylyl cyclase blocker. In conclusion, DA inhibits colonic motility in mice via D2- and D1-like receptors, the latter reducing acetylcholine release from enteric neurons, involving nitrergic and purinergic systems. Whether constitutively active D1-like receptors, linked to adenylyl cyclase pathway, are involved in a tonic inhibitory control of colonic contractility is questioned
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Coleções:
Bases de dados nacionais
/
Espanha
Base de dados:
IBECS
Assunto principal:
Dopamina
/
Receptores de Dopamina D2
/
Receptores de Dopamina D1
/
Colo
/
Contração Muscular
Limite:
Animais
Idioma:
Inglês
Revista:
J. physiol. biochem
Ano de publicação:
2017
Tipo de documento:
Artigo
Instituição/País de afiliação:
Università di Palermo/Italy