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Central oxytocin inhibition of angiotensin-induced salt appetite in rats.
- Source :
-
The American journal of physiology [Am J Physiol] 1992 Dec; Vol. 263 (6 Pt 2), pp. R1347-53. - Publication Year :
- 1992
-
Abstract
- In several models of salt appetite in the rat, stimulated NaCl intake can be severely blunted by treatments associated with pituitary release of oxytocin (OT). Central administration of the potent dipsogen angiotensin II (ANG II) is known to elicit a limited salt appetite as well as thirst, but it has also been reported to stimulate pituitary OT secretion. These results suggest the possibility that the expression of ANG II-induced salt appetite in rats may be inhibited by a simultaneous central release of OT in response to this stimulus. To investigate this possibility, rats were given intracerebroventricular injections of OT-receptor antagonists before administration of 5 ng ANG II intracerebroventricularly in a 1-h two-bottle (water and 0.3 M NaCl) drinking test. This pretreatment resulted in a three- to fourfold potentiation of ANG II-induced saline ingestion, which was most prominent during the first 15 min of the test. OT-receptor antagonism did not, however, interfere with the dipsogenic properties of ANG II, nor did it stimulate saline ingestion alone in the absence of ANG II. Immunocytochemical studies demonstrated that central administration of ANG II at this dose caused pronounced c-fos expression in hypothalamic magnocellular OT and vasopressin neurons and also in OT neurons in parvocellular subdivisions of the paraventricular nucleus. These results therefore demonstrate that central administration of small doses of ANG II activates both magnocellular and parvocellular OT neurons in rats and indicate that some of the activated central OT pathway(s) may mediate an inhibitory effect that limits the salt ingestion induced by this treatment.
- Subjects :
- Angiotensin II antagonists & inhibitors
Angiotensin Receptor Antagonists
Animals
Appetite physiology
Brain cytology
Drinking drug effects
Injections, Intraventricular
Male
Neurons metabolism
Proto-Oncogene Proteins c-fos metabolism
Rats
Rats, Sprague-Dawley
Receptors, Oxytocin
Angiotensin II pharmacology
Appetite drug effects
Brain physiology
Oxytocin physiology
Sodium Chloride
Subjects
Details
- Language :
- English
- ISSN :
- 0002-9513
- Volume :
- 263
- Issue :
- 6 Pt 2
- Database :
- MEDLINE
- Journal :
- The American journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 1336319
- Full Text :
- https://doi.org/10.1152/ajpregu.1992.263.6.R1347