The effects of osmotic stimulation and water availability on c-Fos and FosB staining in the supraoptic and paraventricular nuclei of the hypothalamus.
We studied the effects of osmotic stimulation on the expression of FosB and c-Fos in the supraoptic nucleus (SON) and paraventricular nucleus (PVN). Adult male rats were divided into two groups that were injected with lidocaine (0.1-0.2 ml sc) followed by either 0.9% or 6% NaCl (1 ml/100 g bw sc). After the NaCl injections, the rats were anesthetized and perfused 2, 6, or 8 h after the injections. Their brains were prepared for immunocytochemistry and stained with FosB and c-Fos antibodies. The number of c-Fos-positive cells was significantly increased only at 2 h in the SON and PVN. In contrast, the number of FosB-positive cells was significantly increased at 6, and 8 h in both the SON and PVN. In a second experiment, the effect of water availability on FosB staining 8 h after injections of 6% NaCl was tested in 3 groups of rats: water ad libitum, rats that had no access to water, and rats that were given water 2 h prior to perfusion. FosB staining was significantly reduced in both the SON and the PVN of rats that had ad libitum water compared to the two water-restricted groups. In the third experiment, rats were injected with either 0.9% NaCl or 6% NaCl and were either given ad libitum access to water or water restricted for 6 h after the injections and perfused 24 h after the saline injections. FosB staining was not increased when water was available ad libitum. FosB staining was significantly increased at 24 h in the rats injected with 6% NaCl when water was restricted. Thus, FosB may continue to influence protein expression in the SON and PVN for at least 24 h following acute osmotic stimulation.
Penny
Maurice L
ML
Department of Pharmacology and the Center for Biomedical Neuroscience, University of Texas Health Sciences Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
Bruno
Stacy B
SB
Cornelius
Jennifer
J
Higgs
Karen A N
KA
Cunningham
J Thomas
JT
D000818:Animals; D002452:Cell Count; D049109:Cell Proliferation; D015536:Down-Regulation / Q000502:physiology; D004326:Drinking / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D010121:Oxytocin / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D013495:Supraoptic Nucleus / Q000166:cytology / Q000378:metabolism*; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology; D014667:Vasopressins / Q000378:metabolism; D014882:Water-Electrolyte Balance / Q000502:physiology*
C483820:Fosb protein, rat; D016760:Proto-Oncogene Proteins c-fos; D012462:Saline Solution, Hypertonic; D014157:Transcription Factors; D014667:Vasopressins; D010121:Oxytocin