[Muscarinic acetylcholine receptors of the chick amnion].
Izv Akad Nauk Ser Biol
; (2): 215-22, 2008.
Article
em Ru
| MEDLINE
| ID: mdl-18946994
The presence of muscarinic (M) acetylcholine receptors in the noninnervated chick amnion makes it possible to analyze their functioning with presynaptic effects excluded. The M receptors of the amnion mediating its contraction were identified by testing with selective antagonists: pirenzepine for M1, methoctramine for M2, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) for M3, and tropicamide for M4 receptor subtype. All antagonists acted as competitive inhibitors of M-acetylcholine receptors. With respect to cholinolytic activity estimated from the response to carbacholine (CBC) (-logIC50), the antagonists could be arranged in the following series: 4-DAMP (8.29) > tropicamide (6.97) > pirenzepine (5.85) > methoctramine (5.63). In addition, the effect of forskolin (5 microM), activator of adenylate cyclase (AC), was unidirectional with beta-adrenergic agonists; it blocked CBC-induced contractile activity of the amnion, whereas phospholipase C (1.25 U/ml) stimulated this activity. These data suggest that CBC- or acetylcholine (ACh)-induced contractile activity of the amnion is mediated by M3 acetylcholine receptors. Evaluation of contractile response to ACh by the tonic component usually revealed one pool of M3 acetylcholine receptors. One pool was also revealed after treatment with 4-DAMP, with the Hill coefficient being increased (ACh, n = 1.07; ACh against the 4-DAMP background, n = 1.48). It is possible to detect two pools of M3-acetylcholine receptors on the basis of either phase-frequency or tonic response, i.e., independently of the test parameter.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores Muscarínicos
/
Antagonistas Muscarínicos
/
Âmnio
Limite:
Animals
Idioma:
Ru
Revista:
Izv Akad Nauk Ser Biol
Assunto da revista:
BIOLOGIA
Ano de publicação:
2008
Tipo de documento:
Article
País de publicação:
Federação Russa