Exaggerated response of a vasopressin-enhanced green fluorescent protein transgene to nociceptive stimulation in the rat.
Nociceptive stimulation elicits neuroendocrine responses such as arginine vasopressin (AVP) release as well as activation of the hypothalamo-pituitary-adrenal axis. We have generated novel transgenic rats expressing an AVP-enhanced green fluorescent protein (eGFP) fusion gene, and we examined the effects of nociceptive stimulation on transgene expression in the hypothalamus after subcutaneous injection of saline or formalin into the bilateral hindpaws in these rats. We have assessed (1) AVP levels in plasma and the changes of eGFP mRNA and AVP heteronuclear RNA (hnRNA) in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) using in situ hybridization histochemistry, (2) gene expression changes in distinct magnocellular and parvocellular divisions of the PVN, (3) eGFP fluorescence in the SON, the PVN, the median eminence (ME), and the posterior pituitary gland (PP). Plasma AVP levels were significantly increased 15 min after formalin injection. In the same time period, the AVP hnRNA levels in the PVN were increased, especially in the parvocellular division of the PVN in formalin-injected rats. In the same region, eGFP mRNA levels after formalin injection were also significantly increased to a much greater extent than those of AVP hnRNA. The eGFP fluorescence in the SON, the PVN, the ME, and the PP was markedly increased in formalin-injected rats and especially increased in the parvocellular divisions of the PVN. Together, our results demonstrate robust and rapid changes in the expression of the AVP-eGFP transgene in the rat hypothalamus after acute nociceptive stimulation.
Departments of Physiology and Orthopaedics, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Hitoshi
H
Suzuki
Makoto
M
Kawasaki
Hideo
H
Ohnishi
Hiroki
H
Otsubo
Toyoaki
T
Ohbuchi
Akiko
A
Katoh
Hirofumi
H
Hashimoto
Toru
T
Yokoyama
Hiroaki
H
Fujihara
Govindan
G
Dayanithi
David
D
Murphy
Toshitaka
T
Nakamura
Yoichi
Y
Ueta
D000344:Afferent Pathways / Q000503:physiopathology*; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D005557:Formaldehyde / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics*; D008297:Male; D009994:Osmolar Concentration; D010146:Pain / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D010949:Plasma / Q000187:drug effects / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D055647:Rats, Transgenic; D017208:Rats, Wistar; D012964:Sodium / Q000097:blood; D013495:Supraoptic Nucleus / Q000187:drug effects / Q000378:metabolism; D014667:Vasopressins / Q000097:blood / Q000235:genetics*
D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; C485184:enhanced green fluorescent protein; D014667:Vasopressins; D049452:Green Fluorescent Proteins; D005557:Formaldehyde; D003346:Corticotropin-Releasing Hormone; D012964:Sodium