Deceased 2 August 1999.
Glial Limitans Elasticity Subjacent to the Supraoptic Nucleus
Article first published online: 9 JUL 2004
Journal of Neuroendocrinology
Volume 16, Issue 8, pages 661–668, August 2004
How to Cite
Salm, A. K. and Hawrylak, N. (2004), Glial Limitans Elasticity Subjacent to the Supraoptic Nucleus. Journal of Neuroendocrinology, 16: 661–668. doi: 10.1111/j.1365-2826.2004.01219.x
- Issue published online: 9 JUL 2004
- Article first published online: 9 JUL 2004
- Accepted 27 May 2004
- glial limitans supraoptic nucleus plasticity
Two previous studies from our laboratory have indicated that the ventral glial limitans subjacent to the hypothalamic supraoptic nucleus (SON-VGL) undergoes a reversible thinning upon chronic activation of the magnocellular neuroendocrine cells (MNCs) of the supraoptic nucleus (SON). Numerous other studies have shown that MNC somata hypertrophy with activation. One aim of the current study was to understand better how SON-VGL thinning occurs. A second aim was to quantify overall changes of the MNC somata region due to cellular hypertrophy to compare relative changes in dimensions. Here, we undertook a light microscopic stereological investigation of the SON and the subjacent SON-VGL of Nissl stained material under basal and activated conditions. Astrocyte numbers in the underlying SON-VGL remained stable across hydration state as did the overall volume of the SON-VGL and dendritic zone reference area. How these data are consistent with our earlier observations of SON-VGL thinning was resolved by the finding of a highly significant, 30% increase in the mediolateral dimension of the SON-VGL in dehydrated rats. These observations fit well with previous work from our laboratory that demonstrates a reorientation of SON-VGL astrocytes, from vertical to horizontal, which occurs in the activated SON-VGL. We found a significant, approximately 54%, increase in the overall volume of the MNC region of the SON. No significant rostrocaudal lengthening of the SON was detected, although a trend was evident. All the observed changes reversed with rehydration. These data indicate that elasticity of the SON-VGL acts to accommodate the volume expansion of the MNCs and enables the SON-VGL to continue as an interface between the underlying cerebrospinal fluid in the subarachnoid space and the expanded SON above.