Coexistence of oxytocin and NADPH-diaphorase in magnocellular neurons of the paraventricular and the supraoptic nuclei of the rat hypothalamus.
Nitric oxide (NO), which was firstly identified as an endothelium-derived relaxing factor, has recently been demonstrated to be a neurotransmitter in the central and peripheral nervous systems. In the hypothalamus, abundant nitric oxide synthase (NOS) immunoreactivity and its histochemical marker, NADPH-diaphorase activity, have been demonstrated in the hypothalamo-neurohypophyseal system. In the present study, we examined whether NOS is coexpressed with posterior pituitary hormones in the rat hypothalamus by combination of oxytocin and vasopressin immunofluorescence and NADPH-diaphorase histochemistry. Most oxytocin-immunoreactive neurons in the paraventricular and supraoptic nuclei expressed NADPH-diaphorase activity, but virtually no vasopressin-immunoreactive neurons contained NADPH-diaphorase activity. This suggests that oxytocin neurons are the main source of NO production in the hypothalamic-pituitary system.
Miyagawa
A
A
Department of Anatomy, Kyoto Prefectural University of Medicine, Japan.
Okamura
H
H
Ibata
Y
Y
D000818:Animals; D001479:Basal Ganglia / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D008297:Male; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology / Q000378:metabolism*; D010121:Oxytocin / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013495:Supraoptic Nucleus / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D014667:Vasopressins / Q000276:immunology / Q000378:metabolism
D014667:Vasopressins; D010121:Oxytocin; D009252:NADPH Dehydrogenase