Aldosterone-sensitive NTS neurons are inhibited by saline ingestion during chronic mineralocorticoid treatment.
The nucleus of the solitary tract (NTS) contains a unique subpopulation of neurons that express the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (HSD2). These neurons are mineralocorticoid-sensitive and are activated in association with salt appetite during sodium deficiency. In the absence of sodium deficiency, the HSD2 neurons and sodium appetite are both stimulated by chronic mineralocorticoid administration. After 7 days of treatment with deoxycorticosterone (2 mg/day), an increased number of HSD2 neurons became immunoreactive for the neuronal activity marker c-Fos. When given access to concentrated saline (3% NaCl), deoxycorticosterone-treated rats drank eight times more than vehicle-treated rats. Saline ingestion increased neuronal activation within the medial subdivision of the NTS, but the number of c-Fos-immunoreactive HSD2 neurons was reduced. This finding suggests that the HSD2 neurons are inhibited by signals directly related to saline ingestion, and not simply by the alleviation of sodium deficiency, which does not occur during mineralocorticoid administration.
Geerling
Joel C
JC
Department of Anatomy and Neurobiology-Box 8108, Washington University School of Medicine, 660 S. Euclid Ave. St. Louis, MO 63110 USA.
Loewy
Arthur D
AD
D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2 / Q000187:drug effects / Q000378:metabolism*; D000450:Aldosterone / Q000378:metabolism; D000818:Animals; D003900:Desoxycorticosterone / Q000378:metabolism / Q000494:pharmacology; D005246:Feedback / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D008901:Mineralocorticoids / Q000378:metabolism* / Q000494:pharmacology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000172:deficiency; D012965:Sodium Chloride / Q000378:metabolism* / Q000494:pharmacology; D017673:Sodium Chloride, Dietary / Q000378:metabolism; D012982:Sodium, Dietary / Q000378:metabolism*; D017552:Solitary Nucleus / Q000187:drug effects / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology*
D008901:Mineralocorticoids; D016760:Proto-Oncogene Proteins c-fos; D017673:Sodium Chloride, Dietary; D012982:Sodium, Dietary; D003900:Desoxycorticosterone; D012965:Sodium Chloride; D000450:Aldosterone; D012964:Sodium; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2