Development of the human dorsal nucleus of the vagus Gang Cheng a, ⁎ , Hua Zhu b , Xiangtian Zhou b , Jia Qu b , K.W.S. Ashwell c , G. Paxinos a a Prince of Wales Medical Research Institute, Barker St. Randwick 2031 NSW, Australia b School of Ophthalmology and Optometry, Wenzhou Medical College, 82 Xueyuan Road, Wenzhou, Zhejiang, 325003,China c Department of Anatomy, School of Medical Sciences, The University of New South Wales, 2052, NSW, Australia Accepted 1 January 2007 Abstract The dorsal nucleus of the vagus nerve plays an integral part in the control of visceral function. The aim of the present study was to correlate structural and chemical changes in the developing nucleus with available data concerning functional maturation of human viscera and reflexes. The fetal development (ages 9 to 26 weeks) of the human dorsal nucleus of the vagus nerve has been examined with the aid of Nissl staining and immunocytochemistry for calbindin and tyrosine hydroxylase. By 13 weeks, the dorsal vagal nucleus emerges as a distinct structure with at least two subnuclei visible in Nissl stained preparations. By 15 weeks, three subnuclei (dorsal intermediate, centrointermediate and ventrointermediate) were clearly discernible at the open medulla level with caudal and caudointermediate subnuclei visible at the level of the area postrema. All subnuclei known to exist in the adult were visible by 21 weeks and cytoarchitectonic differentiation of the nucleus was largely completed by 25 weeks. The adult distribution pattern of calbindin and tyrosine hydroxylase immunoreactive neurons was also largely completed by 21 weeks, although morphological differentiation of labeled neurons continued until the last age examined (26 weeks). The structural development of the dorsal nucleus of the vagus nerve appears to occur in parallel with functional maturation of the cardiovascular and gastric movements, which the nucleus controls. © 2007 Elsevier Ireland Ltd. All rights reserved. KEYWORDS Dorsal vagal nucleus; Calbindin; Tyrosine hydroxylase 1. Introduction Parasympathetic motor control of smooth muscle and glands of thoracic and abdominal visceral organs is mediated by efferent fibers of the vagus nerve originating from the dorsal nucleus of the vagus nerve (10N) and/or the nucleus ambiguus (Amb) [1]. Cyto- and chemoarchitecture of adult human 10N has been thoroughly studied by Huang and colleagues [2,3], who divided the nucleus into 8 subregions on the basis of cytoarchitectural criteria: dorsorostral, ventrorostral, rostrointermediate, dor- sointermediate, ventrointermediate, centrointermediate, caudointermediate and caudal subnuclei [2]. On the other hand, such a detailed subdivisional pattern was not observed in a developmental study of human 10N by Nara et al. [1], in ⁎ Corresponding author. Prince of Wales Medical Research Institute, Barker St. Randwick 2031, NSW, Australia. Tel.: +61 2 93991011; fax: +61 2 93991005. E-mail address: gcheng@unsw.edu.au (G. Cheng). 0378-3782/$ - see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.earlhumdev.2007.01.012 available at www.sciencedirect.com www.elsevier.com/locate/earlhumdev Early Human Development (2008) 84, 15–27