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This Article Full Text Full Text (PDF) All Versions of this Article: 586/15/3719    most recent jphysiol.2008.151282v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by De Gobbi, J. I. F. Articles by Johnson, A. K. PubMed PubMed Citation Articles by De Gobbi, J. I. F. Articles by Johnson, A. K. Related Collections Integrative

Departments of
¹ Psychology
² Integrative Physiology
³ Pharmacology
⁴ Cardiovascular Center, University of Iowa, Iowa City, IA 52242-1407, USA
⁵ Department of Physiology and Pathology, School of Dentistry, Paulista State University (UNESP), 14801-903 Araraquara, SP, Brazil
⁶ Department of Physiology, Bioscience Institute, Paulista State University (UNESP), 18618-000 Botucatu, SP, Brazil

The inflation of an intravascular balloon positioned at the superior vena cava and right atrial junction (SVC-RAJ) reduces sodium or water intake induced by various experimental procedures (e.g. sodium depletion; hypovolaemia). In the present study we investigated if the stretch induced by a balloon at this site inhibits a rapid onset salt appetite, and if this procedure modifies the pattern of immunohistochemical labelling for Fos protein (Fos-ir) in the brain. Male Sprague–Dawley rats with SVC-RAJ balloons received a combined treatment of furosemide (Furo; 10 mg (kg bw)^–1) plus a low dose of the angiotensin-converting enzyme inhibitor captopril (Cap; 5 mg (kg bw)^–1). Balloon inflation greatly decreased the intake of 0.3 M NaCl for as long as the balloon was inflated. Balloon inflation over a 3 h period following Furo–Cap treatment decreased Fos-ir in the organum vasculosum of the lamina terminalis and the subfornical organ and increased Fos-ir in the lateral parabrachial nucleus and caudal ventrolateral medulla. The effect of balloon inflation was specific for sodium intake because it did not affect the drinking of diluted sweetened condensed milk. Balloon inflation and deflation also did not acutely change mean arterial pressure. These results suggest that activity in forebrain circumventricular organs and in hindbrain putative body fluid/cardiovascular regulatory regions is affected by loading low pressure mechanoreceptors at the SVC-RAJ, a manipulation that also attenuates salt appetite.

(Received 17 January 2008; accepted after revision 10 June 2008; first published online 12 June 2008)
Corresponding author A. K. Johnson: Department of Psychology, University of Iowa, 11 Seashore Hall E, Iowa City, IA 52242-1407, USA.  Email: alan-johnson{at}uiowa.edu