Specific expression of an oxytocin-enhanced cyan fluorescent protein fusion transgene in the rat hypothalamus and posterior pituitary.
We have generated rats bearing an oxytocin (OXT)-enhanced cyan fluorescent protein (eCFP) fusion transgene designed from a murine construct previously shown to be faithfully expressed in transgenic mice. In situ hybridisation histochemistry revealed that the Oxt-eCfp fusion gene was expressed in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) in these rats. The fluorescence emanating from eCFP was observed only in the SON, the PVN, the internal layer of the median eminence and the posterior pituitary (PP). In in vitro preparations, freshly dissociated cells from the SON and axon terminals showed clear eCFP fluorescence. Immunohistochemistry for OXT and arginine vasopressin (AVP) revealed that the eCFP fluorescence co-localises with OXT immunofluorescence, but not with AVP immunofluorescence in the SON and the PVN. Although the expression levels of the Oxt-eCfp fusion gene in the SON and the PVN showed a wide range of variations in transgenic rats, eCFP fluorescence was markedly increased in the SON and the PVN, but decreased in the PP after chronic salt loading. The expression of the Oxt gene was significantly increased in the SON and the PVN after chronic salt loading in both non-transgenic and transgenic rats. Compared with wild-type animals, euhydrated and salt-loaded male and female transgenic rats showed no significant differences in plasma osmolality, sodium concentration and OXT and AVP levels, suggesting that the fusion gene expression did not disturb any physiological processes. These results suggest that our new transgenic rats are a valuable new tool to identify OXT-producing neurones and their terminals.
Katoh
Akiko
A
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Yahatanishi-ku, Kitakyushu, Japan.
Fujihara
Hiroaki
H
Ohbuchi
Toyoaki
T
Onaka
Tatsushi
T
Young
W Scott
WS
Dayanithi
Govindan
G
Yamasaki
Yuka
Y
Kawata
Mitsuhiro
M
Suzuki
Hitoshi
H
Otsubo
Hiroki
H
Suzuki
Hideaki
H
Murphy
David
D
Ueta
Yoichi
Y
D000818:Animals; D005260:Female; D015870:Gene Expression; D049452:Green Fluorescent Proteins / Q000235:genetics* / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism*; D008297:Male; D010121:Oxytocin / Q000235:genetics* / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013495:Supraoptic Nucleus / Q000378:metabolism; D019076:Transgenes; D014667:Vasopressins / Q000235:genetics / Q000378:metabolism
C485182:Cyan Fluorescent Protein; D011993:Recombinant Fusion Proteins; D014667:Vasopressins; D049452:Green Fluorescent Proteins; D010121:Oxytocin