Involvement of brainstem catecholaminergic inputs to the hypothalamic paraventricular nucleus in estrogen receptor alpha expression in this nucleus during different stress conditions in female rats.
In the present study, we determined the involvement of brainstem catecholaminergic inputs to the paraventricular nucleus (PVN) on estrogen receptor alpha (ERalpha) expression in this nucleus during conditions of 48-h fasting, 2-deoxy-d-glucose (2DG)-induced acute glucoprivation and 1-h immobilization, in ovariectomized rats. Our approach was to examine the effect of lesioning catecholaminergic inputs to the PVN using DSAP [saporin-conjugated anti-DBH (dopamine-beta-hydroxylase)]. Bilateral injection of DSAP into the PVN, 2 wk before stress, prevented fasting-, glucoprivation-, and immobilization-induced increase in ERalpha-immunopositive cells in the PVN. The DBH-immunoreactive (ir) terminals in the PVN were severely depleted by DSAP injection in all experimental groups. Among the brainstem noradreneregic cell groups examined, DBH-ir cell bodies were significantly reduced in the A2 region of all experimental groups treated with DSAP compared with the saporin- and vehicle-injected controls. PVN DSAP injection caused a small, but not significant, decrease in A1 DBH-ir cell bodies in fasted and immobilized rats, and a significant, but slight, reduction in A1 DBH-ir cell bodies of iv 2DG- injected rats compared with PVN vehicle-injected or PVN saporin-injected controls. The A6 DBH-ir cell bodies in all experimental groups treated with DSAP, saporin, or vehicle did not show any significant difference. These results suggest that the brainstem catecholaminergic inputs to the PVN, especially from the A2 cell group, may play a major role in mediating the induction of ERalpha expression in the PVN by metabolic stressors such as fasting, acute glucoprivation, and less specific stressors, such as immobilization, in female rats.
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
Maria Amelita C
MA
Estacio
Hiroko
H
Tsukamura
Beverly A S
BA
Reyes
Yoshihisa
Y
Uenoyama
Helen
H
I'anson
Kei-Ichiro
K
Maeda
D000818:Animals; D001933:Brain Stem / Q000166:cytology*; D002395:Catecholamines / Q000378:metabolism; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D009434:Neural Pathways; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology; D013312:Stress, Physiological / Q000378:metabolism*
D002395:Catecholamines; D047628:Estrogen Receptor alpha