Morphometrical and microdensitometrical studies on phenylethanolamine-N-methyltransferase- and neuropeptide Y-immunoreactive nerve terminals and on glucocorticoid receptor-immunoreactive nerve cell nuclei in the paraventricular hypothalamic nucleus in adult and old male rats.
The phenylethanolamine-N-methyltransferase- and neuropeptide Y-immunoreactive nerve terminal profiles and the glucocorticoid receptor-immunoreactive nuclear profiles have been characterized in the parvocellular part of the paraventricular hypothalamic nucleus of the adult (3 month) and the old (24 month) male rat. The phenylethanolamine-N-methyltransferase-, neuropeptide Y- and glucocorticoid receptor-immunoreactive structures have been demonstrated by means of the indirect immunoperoxidase procedure and analysed in a quantitative way by means of morphometrical and microdensitometrical approaches using both semiautomatic and automatic image analysis. During aging there is (a) a marked reduction in the number of neuropeptide Y-immunoreactive profiles, a moderate reduction of phenylethanolamine-N-methyltransferase-immunoreactive profiles and a small reduction in the number of glucocorticoid receptor-immunoreactive profiles without a significant change in the evenness of distribution of such profiles as evaluated by means of Gini's index; (b) a loss of the significant correlation in the distribution of the glucocorticoid receptor- and phenylethanolamine-N-methyltransferase-immunoreactive profiles at the two most caudal levels analysed (A5150 and A5270 micron) while a significant correlation developed between these two distributions at a more rostral level (A5400 micron); (c) a substantial decline in the overlap area of the glucocorticoid receptor- and phenylethanolamine-N-methyltransferase-immunoreactive profiles at four out of five rostrocaudal levels analysed; (d) a marked reduction in the density-intensity of the neuropeptide Y-immunoreactive profiles and a small significant reduction in the density-intensity of the phenylethanolamine-N-methyltransferase-immunoreactive profiles without any associated changes in the intensity of the glucocorticoid receptor-immunoreactive profiles. Furthermore, three-dimensional reconstructions of the overall distribution of the glucocorticoid receptor-, phenylethanolamine-N-methyltransferase- and neuropeptide Y-immunoreactive structures have been made in the paraventricular hypothalamic nucleus of the adult male rat. The present results indicate a reduction of neuropeptide Y- and phenylethanolamine-N-methyltransferase-immunoreactive nerve terminal profiles in the parvocellular part of the paraventricular hypothalamic nucleus during aging. These results may in part reflect a loss of neuropeptide Y-like peptides in phenylethanolamine-N-methyltransferase-immunoreactive nerve terminals of the paraventricular hypothalamic nucleus, favouring our view that during aging the modulatory peptides may be lost, leading to a loss of
Zoli
M
M
Department of Human Physiology, University of Modena, Italy.
Agnati
L F
LF
Fuxe
K
K
Zini
I
I
Merlo Pich
E
E
Grimaldi
R
R
Härfstrand
A
A
Goldstein
M
M
Wikström
A C
AC
Gustafsson
J A
JA
D000375:Aging / Q000378:metabolism*; D000818:Animals; D004837:Epinephrine / Q000378:metabolism* / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism* / Q000502:physiology; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism* / Q000502:physiology; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011965:Receptors, Glucocorticoid / Q000378:metabolism* / Q000502:physiology
D009478:Neuropeptide Y; D011965:Receptors, Glucocorticoid; D010625:Phenylethanolamine N-Methyltransferase; D004837:Epinephrine