Expression of muscarinic acetylcholine receptors in turkey cardiac chambers

Autor: Sandra Hoffmann, Caroline Schoeller, Ralf Regenthal, Stephanie Adolph, Getu Abraham
Rok vydání: 2020
Předmět:
Zdroj: Research in veterinary science. 136
ISSN: 1532-2661
Popis: The aim of the present study was to characterize the specific binding sites for [N-methyl-3H]-scopolamine ([3H]-NMS), a radioligand for labeling muscarinic acetylcholine receptors (mAChRs), in membranes of four heart chambers obtained from adult male British United Turkey (BUT) Big 6 (“meat-type”) and Crollwitzer (“wild-type”) turkeys. MAChR subtypes were examined by inhibiting [3H]-NMS binding with subtype selective non-labelled receptor antagonists. In all left and right atria as well as left and right ventricles of both turkey breeds, the specific [3H]-NMS binding was saturable, reversible and of high affinity (KD range: 0.5–1.0 nM). The maximum receptor density (Bmax) was not significantly different between the four cardiac chambers of BUT Big 6 turkeys, but a significant difference was found between atria and ventricles of Crollwitzer turkeys. Moreover, significant lower Bmax was found in the atria of Crollwitzer turkeys than in the atria of BUT Big 6, while the ventricular Bmax was significantly higher. In all cardiac chambers, unlabeled mAChR antagonists competed for specific [3H]-NMS binding sites in a concentration-dependent manner, suggesting the presence of the M3 and M2 receptor subtypes, whereby the latter was the predominant subtype. The presence of the M1 subtype could not be excluded. In conclusion, there was a difference between BUT Big 6 (“meat-type”) and Crollwitzer (“wild-type”) turkeys with regard to receptor density in heart chambers with dominant M2 and M3 receptor subtypes.
Databáze: OpenAIRE
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