Hassall C J, Stanford S C, Burnstock G, Buckley N J
Department of Anatomy and Developmental Biology, University College London, U.K.
Neuroscience. 1993 Oct;56(4):1041-8. doi: 10.1016/0306-4522(93)90149-a.
Expression of the messenger RNAs encoding the five different muscarinic acetylcholine receptor subtypes was examined in intracardiac neurons from the rat and guinea-pig heart by in situ hybridization techniques. Newborn guinea-pig intracardiac neurons were studied in dissociated cell culture preparations employing both 35S- and digoxigenin-labelled oligonucleotide probes specific for the m1, m2, m3, m4 or m5 muscarinic receptor messenger RNAs. When 35S-tailed oligonucleotides were used, all intracardiac neurons in culture were found to express m1, m2, m3 and m4, but not m5 messenger RNAs. However after hybridization with digoxigenin-tailed probes, only m1 and m2 transcripts were detected. This may reflect differences in the sensitivity of the two techniques. Further to these experiments, intracardiac ganglia in sections of adult rat heart were studied employing m1-, m2-, m3- or m4-specific, 35S-labelled oligonucleotides, and again, all intracardiac neurons expressed messenger RNA for each of these four muscarinic receptor subtypes. Atrial myocytes in culture were only labelled by [35S]- and digoxigenin-tailed m2 oligonucleotides. No other heart cell type seen expressed messenger RNA for any of the muscarinic receptors. The expression of four different muscarinic receptor transcripts by intrinsic neurons of the heart provides the molecular basis for the diverse muscarinic actions observed in these and other autonomic ganglia.
采用原位杂交技术，检测了大鼠和豚鼠心脏心内神经元中编码五种不同毒蕈碱型乙酰胆碱受体亚型的信使核糖核酸的表达情况。在新生豚鼠的心内神经元解离细胞培养物中，使用针对毒蕈碱型受体m1、m2、m3、m4或m5信使核糖核酸的35S标记和地高辛配体标记的寡核苷酸探针进行研究。当使用35S尾寡核苷酸时，培养物中的所有心内神经元均表达m1、m2、m3和m4信使核糖核酸，但不表达m5信使核糖核酸。然而，在用含地高辛配体尾的探针杂交后，仅检测到m1和m2转录本。这可能反映了这两种技术在灵敏度上的差异。在这些实验的基础上，使用m1、m2、m3或m4特异性的35S标记寡核苷酸对成年大鼠心脏切片中的心内神经节进行了研究，同样，所有心内神经元均表达这四种毒蕈碱型受体亚型各自的信使核糖核酸。培养的心房肌细胞仅被[35S]标记和含地高辛配体尾的m2寡核苷酸标记。未见其他任何心脏细胞类型表达任何毒蕈碱型受体的信使核糖核酸。心脏固有神经元对四种不同毒蕈碱型受体转录本的表达为在这些以及其他自主神经节中观察到的多样的毒蕈碱作用提供了分子基础。
