Sodium depletion induces Fos immunoreactivity in circumventricular organs of the lamina terminalis.
Acute sodium depletion by peritoneal dialysis (PD) induces c-fos expression in the subfornical organ (SFO) and organum vasculosum laminae terminalis (OVLT), in conscious rats. Fos immunoreactive (Fos-ir) neurons detected by immunohistochemistry first appeared in these nuclei 60 min after PD, increased gradually in the next 4 h and remained high for 27 h following PD. Fos-ir cells were distributed throughout the body of SFO, being the core of the posterior sections preferentially activated, whereas Fos-ir neurons occurred around the periphery of OVLT (annular disposition). When rats were allowed to drink sodium salt (1.8% NaCl) 24 h after PD, there was a marked reversion of the c-fos expression in the OVLT and a comparatively smaller effect in the SFO. Intracerebroventricular infusion of hypertonic CSF (170 mM NaCl) from 30 min before and during 4 h after PD, significantly inhibited the c-fos expression in both nuclei. These results demonstrate that an acute body sodium deficit induces c-fos activity in SFO and OVLT neurons, indicating the special role of these structures in sodium balance regulation. They also show that the sodium-depletion-induced production of Fos in neurons of the lamina terminalis can be modulated by central or systemic reposition of sodium.
Vivas
L
L
Instituto de Investigación Médica Mercedes y Martin Ferreyra, Córdoba, Argentina.
Pastuskovas
C V
CV
Tonelli
L
L
D000704:Analysis of Variance; D000818:Animals; D002552:Cerebral Ventricles / Q000737:chemistry*; D005069:Evaluation Studies as Topic; D007031:Hypothalamus / Q000737:chemistry*; D007150:Immunohistochemistry; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis*; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis*; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013356:Subfornical Organ / Q000737:chemistry*
D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D012964:Sodium