Ultrastructural evidence of sexual dimorphism in supraoptic neurons: a morphometric study

Paula‐Barbosa, M. M.; Sousa, Nuno; Madeira, M. Dulce

doi:10.1007/bf01181315

Cited by 20 publications

(5 citation statements)

References 33 publications

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“…Although studies in human brain material have innate factors that cannot be controlled for, our data are strongly supported by similar results in well‐controlled animal experiments ( 11–13). There were a number of very high and low values that should be mentioned separately.…”

Section: Discussionsupporting

confidence: 82%

“…These data are consistent with an earlier report on rats, where the volume of the SON was found to be larger in males than in females ( 12). A higher activity of SON neurones in male rats compared to females has also been suggested by the presence of larger cell body and cell nucleus size ( 12), nucleolar volume and area of the rough endoplasmic reticulum ( 13). Furthermore, the volume of the neurosecretory granules in the SON neurones was larger in males compared with females ( 13).…”

mentioning

confidence: 95%

“…A higher activity of SON neurones in male rats compared to females has also been suggested by the presence of larger cell body and cell nucleus size ( 12), nucleolar volume and area of the rough endoplasmic reticulum ( 13). Furthermore, the volume of the neurosecretory granules in the SON neurones was larger in males compared with females ( 13). These data provided clear evidence for the idea that SON neurones in male rats are functionally more active than in females ( 14).…”

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confidence: 95%

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Activity of Vasopressinergic Neurones of the Human Supraoptic Nucleus os Age‐ and Sex‐Dependent

Ishunina

Salehi

Hofman

et al. 1999

J Neuroendocrinology

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In the human hypothalamus, arginine-vasopressin (AVP) is produced for a major part by the neurones of the supraoptic nucleus (SON). Since plasma AVP levels in men were reported to be higher than those of women and we did not find a sex difference in the neurone number, a higher vasopressinergic neurone activity was supposed to be present in the SON of men. Therefore we studied the size of the Golgi-apparatus (GA), which has been demonstrated previously to be a sensitive parameter for protein synthetic ability of neurones, in 15 men and 17 women ranging in age from 29 to 94 years. A polyclonal antibody against immunoaffinity purified MG-160, a sialoglycoprotein of the medial cisternae of the GA was applied on paraffin-embedded sections containing the dorsolateral SON (dl-SON) from which 90-95% of neurones are vasopressinergic. SON areas that contain oxytocin (OT) cells were excluded on the basis of adjacent sections stained with a monoclonal antibody against OT. By means of an image analysis system the size of the GA and the cellular profile area were determined in dl-SON neurones with a nucleolus. Our results showed indeed an age-dependent sex difference in the size of the GA that appeared to be twice as large in young men (< or = 50 years old) than in young women of the same age. The size of the GA increased with age in women but not in men. In addition, the mean cell profile area, another measure for neuronal activity, was significantly larger in young men than in young women and was in old women larger than in young women. In conclusion, these data show the presence of a sex-dependent age-difference in the activity of vasopressinergic neurones in dl-SON which may relate to differences in AVP and sex hormone levels and kidney AVP receptors.

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Section: Discussionsupporting

confidence: 82%

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confidence: 95%

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confidence: 95%

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Activity of Vasopressinergic Neurones of the Human Supraoptic Nucleus os Age‐ and Sex‐Dependent

Ishunina

Salehi

Hofman

et al. 1999

J Neuroendocrinology

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“…The morphological sex-related differences recognized in the CNS might occur as a secondary response to steroidinduced sexual differentiation of peripheral organs (Fishman et al, 1990;Madeira et al, 1993;Paula-Barbosa et al, 1993). However, most frequently, they develop as a consequence of a direct steroid hormonal action (McEwen, 1981;Breedlove, 1992), i.e., as a result of the interaction of gonadal steroids with target cells that display appropriate receptors for them.…”

Section: Sexual Dimorphismmentioning

confidence: 99%

Age and sex do not affect the volume, cell numbers, or cell size of the suprachiasmatic nucleus of the rat: An unbiased stereological study

Madeira¹,

Sousa²,

Santer

et al. 1995

J of Comparative Neurology

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121

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The circadian rhythms displayed by numerous biological functions are known to be sex specific and affected by aging. It has not been settled yet whether the sex- and age-related characteristics of circadian rhythms derive from changes in the anatomy of the suprachiasmatic nucleus. To shed light on these issues, we applied unbiased stereological techniques to estimate the volume of the suprachiasmatic nucleus as well as the total number of its cells and the mean volume of their somata and nuclei in progressively older groups of male and female Wistar rats (aged 1, 6, 12, 18, 24, and 30 months). The volume of the nucleus was estimated with the Cavalieri principle on serial sections. The total numbers of neurons and astrocytes were estimated by applying the optical fractionator, and the mean somatic and nuclear volumes of cells were estimated by using isotropic, uniform random sections and the nucleator method. On average, the volume of the suprachiasmatic nucleus was 0.044 mm3, and the total number of neurons and astrocytes was 17,400. Cells of the dorsomedial and ventrolateral components of the nucleus, which are morphologically different, have identical mean perikaryal and nuclear volumes, which we estimated to be 750 microns3 and 400 microns3, respectively. We further demonstrated that, at all ages analysed, the volume of the suprachiasmatic nucleus, the total cell number, and the mean somatic and nuclear volumes of its cells are affected neither by the age nor by the sex of the animal, regardless of the presence of sex- and age-related variations in circadian rhythms. However, the possibility that females may display changes in the volume of the suprachiasmatic nucleus at older ages cannot be ruled out. No effect of aging was observed in the total number of neurons or in the total number of astrocytes.

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“…These findings suggested that AVP neurons are more active in males than in females. Indeed, several studies reported clear sex differences in AVP-ergic systems in the rat [6, 7]and in golden hamsters [8]. Recently, we observed that the Golgi apparatus (GA) size and soma size of human SON vasopressinergic neurons is significantly smaller in young females as compared to those in males and elderly …”

Section: Introductionmentioning

confidence: 92%

Sex- and Age-Related P75 Neurotrophin Receptor Expression in the Human Supraoptic Nucleus

Ishunina¹,

Salehi²,

Swaab³

2000

Neuroendocrinology

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The human supraoptic nucleus (SON) is the main production site of plasma vasopressin. Previously, using the Golgi apparatus and cell size as measures for neuronal metabolic activity, an activation of vasopressinergic neurons was found during ageing in the human SON in women but not in men. We hypothesized that the low-affinity neurotrophin receptor p75 (p75^NTR) might be involved in the mechanism of activation of vasopressin neurons in postmenopausal women, since this receptor was found to be expressed in the SON neurons of aged individuals, and because p75^NTR expression was shown to be suppressed by estrogens. Therefore, we investigated whether p75^NTR immunoreactivity in the SON neurons was age- and sex-dependent. For this purpose, we studied paraffin sections of the SON in 32 postmortem brains of control patients ranging in age from 29 to 94 years with an anti-p75^NTR antibody and determined the area of p75^NTR immunoreactivity per neuron using an image analysis system. To study whether the p75^NTR might also participate in the activation of SON neurons, we related Golgi apparatus size to the area of p75^NTR immunoreactivity per cell in the same patients. We found that the area of p75^NTR immunoreactivity per cell correlated indeed significantly with age and with Golgi apparatus size only in women but not in men. Therefore, our results suggest that p75^NTR is involved in postmenopausal activation of vasopressinergic neurons in the human SON.

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Ultrastructural evidence of sexual dimorphism in supraoptic neurons: a morphometric study

Cited by 20 publications

References 33 publications

Activity of Vasopressinergic Neurones of the Human Supraoptic Nucleus os Age‐ and Sex‐Dependent

Activity of Vasopressinergic Neurones of the Human Supraoptic Nucleus os Age‐ and Sex‐Dependent

Age and sex do not affect the volume, cell numbers, or cell size of the suprachiasmatic nucleus of the rat: An unbiased stereological study

Sex- and Age-Related P75 Neurotrophin Receptor Expression in the Human Supraoptic Nucleus

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