Krammer E B
Proc Natl Acad Sci U S A. 1978 May;75(5):2507-11. doi: 10.1073/pnas.75.5.2507.
Integration of our own morphological observations into recent ultrastructural, biochemical, and neuropharmacological results on the carotid body led to a new hypothesis on chemoreceptor function: (i) Glomus cells with small dense-cored vesicles (type IB cells) that store norepinephrine are chemoreceptors. (ii) Glomus cells with large dense-cored vesicles (type IA), which are postsynaptic to the other glomus cell type and presynaptic to afferent nerve endings, are dopaminergic interneurons that suppress the afferent discharge frequency during normoxia by releasing dopamine. (iii) The hypoxic stimulus causes the chemoreceptive cell to release the stored norepinephrine, which in turn brings about disinhibition of the afferent nerve endings by inhibition of the interneuron. (iv) Afferent nerve endings and interneurons interact through reciprocal synapses that form a short inhibitory feedback loop. We propose that information in the carotid body is processed in a fashion graded rather than digital, providing a fine adjusted cooperation of all elements.
将我们自己的形态学观察结果与最近关于颈动脉体的超微结构、生化和神经药理学研究结果相结合，得出了一个关于化学感受器功能的新假说：（i）含有储存去甲肾上腺素的小致密核心囊泡的球细胞（IB型细胞）是化学感受器。（ii）含有大致密核心囊泡的球细胞（IA型），它是另一种球细胞类型的突触后细胞，也是传入神经末梢的突触前细胞，是多巴胺能中间神经元，在常氧状态下通过释放多巴胺来抑制传入放电频率。（iii）低氧刺激导致化学感受细胞释放储存的去甲肾上腺素，这反过来又通过抑制中间神经元来解除对传入神经末梢的抑制。（iv）传入神经末梢和中间神经元通过相互突触相互作用，形成一个短的抑制性反馈回路。我们提出，颈动脉体中的信息是以分级而非数字的方式处理的，从而实现所有元件的精细调节协作。
