open access

Vol 62, No 2 (2003)
ORIGINAL ARTICLES
Published online: 2003-02-27
Submitted: 2012-02-06
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Ultrastructure of the ventromedial hypothalamic nucleus in fasted and refed young and old rats

Jolanta Kubasik-Juraniec, Zbigniew Kmieć, Cecylia Tukaj, Anna Adamowska, Grażyna Kotlarz, Leszek Pokrywka, Andrzej Myśliwski
Folia Morphol 2003;62(2):89-98.

open access

Vol 62, No 2 (2003)
ORIGINAL ARTICLES
Published online: 2003-02-27
Submitted: 2012-02-06

Abstract

Many hypothalamic nuclei are involved in the regulation of food intake and energy homeostasis. An ultrastructural investigation of the hypothalamic ventromedial nucleus (VMN), a hypothetical "satiety centre" was performed to explore the morphological basis of altered feeding behaviour of old rats in an experimental model of fasting/refeeding. Young (5 months old, n = 12) and old (24 months old, n = 12) male Wistar rats were fasted for 48 hours, then refed for 24 hours and sampled thereafter. Brain tissue was fixed by perfusion, histological and ultrathin sections were obtained by routine methods. Although food intake was similar in control young and old rats, during refeeding old animals consumed less chow than young ones. The EM analysis of VMN neurones of old control rats revealed, besides typical age-related residual bodies, deep indentations of the nuclear envelope and the presence of long, undulating rough endoplasmic reticulum cisternae in the cell periphery. In both young and old rats fasting for 48 hours led to the expansion of Golgi complexes and increased folds of the nuclear envelope, which is suggestive of enhanced cellular activity of the VMN neurones. These fasting-induced alterations were sustained in the VMN neurones of refed rats in both age groups. The results showed that the VMN neurones of old control rats differ at the ultrastructural level from young ones. However, starvation and subsequent refeeding cause similar alterations in the hypothalamic neurones of "satiety centre" of both young and old rats.

Abstract

Many hypothalamic nuclei are involved in the regulation of food intake and energy homeostasis. An ultrastructural investigation of the hypothalamic ventromedial nucleus (VMN), a hypothetical "satiety centre" was performed to explore the morphological basis of altered feeding behaviour of old rats in an experimental model of fasting/refeeding. Young (5 months old, n = 12) and old (24 months old, n = 12) male Wistar rats were fasted for 48 hours, then refed for 24 hours and sampled thereafter. Brain tissue was fixed by perfusion, histological and ultrathin sections were obtained by routine methods. Although food intake was similar in control young and old rats, during refeeding old animals consumed less chow than young ones. The EM analysis of VMN neurones of old control rats revealed, besides typical age-related residual bodies, deep indentations of the nuclear envelope and the presence of long, undulating rough endoplasmic reticulum cisternae in the cell periphery. In both young and old rats fasting for 48 hours led to the expansion of Golgi complexes and increased folds of the nuclear envelope, which is suggestive of enhanced cellular activity of the VMN neurones. These fasting-induced alterations were sustained in the VMN neurones of refed rats in both age groups. The results showed that the VMN neurones of old control rats differ at the ultrastructural level from young ones. However, starvation and subsequent refeeding cause similar alterations in the hypothalamic neurones of "satiety centre" of both young and old rats.
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Keywords

ageing; ventromedial nucleus; electron microscopy; fasting; refeeding

About this article
Title

Ultrastructure of the ventromedial hypothalamic nucleus in fasted and refed young and old rats

Journal

Folia Morphologica

Issue

Vol 62, No 2 (2003)

Pages

89-98

Published online

2003-02-27

Bibliographic record

Folia Morphol 2003;62(2):89-98.

Keywords

ageing
ventromedial nucleus
electron microscopy
fasting
refeeding

Authors

Jolanta Kubasik-Juraniec
Zbigniew Kmieć
Cecylia Tukaj
Anna Adamowska
Grażyna Kotlarz
Leszek Pokrywka
Andrzej Myśliwski

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