Prejunctional muscarinic autoreceptors on horse airway cholinergic nerves.
Life Sci
; 56(25): 2255-62, 1995.
Article
em En
| MEDLINE
| ID: mdl-7791513
ABSTRACT
Muscarinic autoreceptors on horse airway cholinergic nerves were studied by examining the effects of muscarinic receptor antagonists on electrical field stimulation (EFS)-induced acetylcholine (ACh) release in trachealis preparations. All the antagonists including atropine (non-selective), pirenzepine (M1-selective), AF-DX 116 (M2-selective), and hexahydrosiladifenidol (M3-selective) augmented ACh release concentration-dependently. The augmentation was not due to displacement of ACh molecules from tissue receptors into the bath liquid because incubation with atropine after EFS had no influence on the measured amount of ACh. Hexahydrosiladifenidol was more potent in inhibiting ACh-induced muscle contraction, which is known to be mediated by M3 receptors, than in augmenting ACh release. The maximal ACh release rate in response to the selective antagonists was much less than that following atropine. Furthermore, the concentrations of the selective antagonists required to augment ACh release far exceeded their KdS for M1, M2, or M3 receptors. These observations suggest that the muscarinic autoreceptors on horse airway cholinergic nerves may belong to a novel subtype.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Traqueia
/
Fibras Colinérgicas
/
Receptores Muscarínicos
Limite:
Animals
Idioma:
En
Revista:
Life Sci
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Estados Unidos