Muscarinic receptors in equine airways.
Vet Res Commun
; 26(8): 637-50, 2002 Dec.
Article
en En
| MEDLINE
| ID: mdl-12507038
The distribution of muscarinic receptors in equine airways was investigated using autoradiography. Frozen sections of tissue from six different levels in the bronchial tree, from the trachea to the distal bronchioles, were incubated in vitro with 1.5 nmol/L of the muscarinic receptor antagonist 1-[N-methyl-3H]scopolamine methyl chloride (3H-NMS). In addition, the subtype pattern of muscarinic receptors was investigated in equine tracheal smooth muscle using radioligand binding with methoctramine, tripinamidc, 4-DAMP-methiodide and pirenzipine as competitors against the binding of 1.3 nmol/L 3H-NMS. The autoradiograms showed specific labelling indicating a high density of muscarinic receptors in smooth-muscle tissue in all levels of the airway tree investigated. Besides muscle tissue, subepithelial glands were the only structures specifically labelled. The dominating subtypes in tracheal smooth muscle investigated with radioligand binding studies were found to be M2 and M4, as both methoctramine (pKd = 8.5) and tripinamide (pKd = 8.6 and 6.7 for two different sites) showed high affinity. The density of the M3-muscarinic receptor subtype was low, but this subtype could be detected with statistical significance when methoctramine was used as the competitor against 3H-NMS binding.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Tráquea
/
Bronquios
/
Receptores Muscarínicos
/
Caballos
Límite:
Animals
Idioma:
En
Revista:
Vet Res Commun
Año:
2002
Tipo del documento:
Article
País de afiliación:
Suecia
Pais de publicación:
Suiza