Brain expansion in the chick embryo initiated by experimentally produced occlusion of the spinal neurocoel

Wiley - Tập 268 Số 2 - Trang 147-159 - 2002
Mary E. Desmond1, Michael L. Levitan
1Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085, USA. [email protected]

Tóm tắt

AbstractThe brain expands in the early chick embryo from pressure generated by accumulation of cerebrospinal fluid (CSF) in a closed neural tube. The sealing of the neural tube occurs as the result of occlusion of the spinal neurocoel rostral to and before closure of the posterior neuropore. We have previously demonstrated the dependence of normal brain expansion upon intraluminal pressure. We had yet to demonstrate, however, that brain expansion actually depends upon natural occlusion of the spinal neurocoel. To demonstrate such dependence, we experimentally occluded the spinal neurocoels of embryos 5 hr younger than stage 11 embryos (in which occlusion of the neurocoel occurs naturally). The stage 10 chick embryos were cultured ex ovo and critically staged, and their spinal neurocoels were occluded using microcautery. All embryos were photographed immediately and at 5, 12, and 24 hr after cautery. Serial sections were made of selected embryos, in which the areas of both the brain and the head were measured. Wilcoxon‐Mann‐Whitney rank‐sum nonparametric tests, Hodges‐Lehmann estimators, bootstrapping techniques, and resampling randomization tests were used to determine whether the increases in the brain and head areas for the experimental embryos were significantly different from those of the control embryos during three distinct intervals of expansion: 0–5, 5–12, and 0–12 hr. From 0 to 5 hr, the brains of the precociously occluded embryos expanded significantly more than the brains of the non‐occluded controls. From 5 to 12 hr, the brains of the embryos with naturally occluded neurocoels grew significantly larger than the brains of the embryos with precociously occluded neurocoels. At 12 hr, there appeared to be no difference in brain size for these two groups. We conclude that the data support the hypothesis that brain expansion is directly dependent upon occlusion of the spinal neurocoel. Anat Rec 268:147–159, 2002. © 2002 Wiley‐Liss, Inc.

Từ khóa


Tài liệu tham khảo

10.1002/(SICI)1097-0185(199812)252:4<499::AID-AR1>3.0.CO;2-1

10.1016/0012-1606(74)90316-9

10.1016/0012-1606(77)90364-5

10.1002/ar.1092040112

10.1002/ar.1092120214

10.1002/cne.902350406

Desmond ME, 1986, Evaluation of the roles of intrinsic and extrinsic factors in occlusion of the spinal neurocoel during rapid brain enlargement in the chick embryo, J Embryol Exp Morphol, 97, 26

Desmond ME, 1989, Precocious occlusion of the spinal cord in chick embryos results in precocious expansion of the brain, Anat Rec, 223, 32A

10.1002/cne.903190205

10.1002/aja.1001970407

Gardner JW, 1975, The dysraphic states from syringomyelia to anecephaly, 201

10.1002/jmor.1050880104

Hollander M, 1999, Nonparametric statistical methods, 125

10.1159/000121188

10.1002/jss.400050309

Jacobson AG, 1981, Morphogenesis and pattern formation, 233

Li XY, 1991, Modulation of Na+/K+ATPase pumps in the heart of the chick embryo influences brain expansion, Soc Neurosci Abstr, 17, 21

10.1159/000120432

10.1002/aja.1001750402

Sandor S, 1969, A new method for in ovo time lapse cinematography of the chick embryo during the first three days of development, Res Film, 6, 429

10.1002/ar.1092090211

10.1002/jez.1402300309

10.1016/0012-1606(85)90353-7

10.1002/cne.902460404

Summerbell D, 1976, A descriptive study of the rate of elongation and differentiation of the skeleton of the developing chick wing, J Embryol Exp Morphol, 35, 241

10.1002/ar.1090580309

Thông tin
Thông tin xuất bản

Wiley

Tập 268 Số 2

147-159

Thông tin tác giả