Effect of intravenous captopril on c-fos expression induced by sodium depletion in neurons of the lamina terminalis.
Peripheral administration of the angiotensin converting enzyme (ACE) inhibitor, captopril, and the central infusion of sarile, an angiotensin II (Ang II) receptor antagonist, were used to evaluate the role of renal and brain generated Ang II in sodium depletion-induced production of Fos in cells of the subfornical organ (SFO) and organum vasculosum lamina terminalis (OVLT). Pretreatment with intravenous captopril (100 mg/kg) significantly inhibited the c-fos expression induced by sodium depletion in the SFO and OVLT. In contrast, continuous intracerebroventricular infusion of sarile (22.5 micrograms/4.5 h, 5 microliters/h) did not affect the expected pattern of c-fos expression observed in both nuclei, 4 h after peritoneal dialysis. These results show that systemic interference with the angiotensin system of renal origin by captopril inhibited the production of Fos induced by sodium depletion in cells of the SFO and OVLT. These findings are consistent with the hypothesis that a rise in peripheral Ang II levels, triggered by sodium deficiency, could be an important mediator of the physiological and behavioral responses that lead to the restoration of sodium balance. In addition, this study suggests that increased circulating Ang II levels in response to body sodium deficit can directly stimulate neural pathways in the SFO and OVLT.
Pastuskovas
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C
Instituto de Investigación Médica Mercedes y Martin Ferreyra, Córdoba, Argentina.
Vivas
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L
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000494:pharmacology; D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D002216:Captopril / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology; D010530:Peritoneal Dialysis; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000172:deficiency*; D013356:Subfornical Organ / Q000166:cytology
D000806:Angiotensin-Converting Enzyme Inhibitors; D016760:Proto-Oncogene Proteins c-fos; D000804:Angiotensin II; D015059:1-Sarcosine-8-Isoleucine Angiotensin II; D002216:Captopril; D012964:Sodium