Acute sodium depletion modifies septo-preoptic neuron sensitivities to neurohormones

Brain Res. 1998 Mar 16;787(1):171-4. doi: 10.1016/s0006-8993(98)00038-9.

Abstract

Sodium (Na+) depletion induces sodium appetite to replenish Na+ loss. It appears to be a consequence of enhanced levels of aldosterone (Aldo) and angiotensin II (AII) in the plasma as well as in the brain. Mineralocorticoid pretreatment modifies the sensitivity of septo-preoptic neurons to locally applied AII and Aldo. Therefore, we investigated septo-preoptic neuronal sensitivities to AII and Aldo, as well as to the specific AII type-1 receptor (AT-1) non-peptide antagonist losartan (Los) and to the specific AII type-2 receptor (AT-2) non-peptide antagonist PD123319 after one Na+ depletion without repletion. We found that one Na+ depletion induced increases in the proportion of neurons inhibited by iontophoretic application of AII (20.5% vs. 7.8%, p=0.004) whereas, the proportion of neurons excited by Aldo was increased, (23.7% vs. 5%, p=0.001). Moreover, the proportion of neurons changing sensitivity to AII after one application of Aldo was increased in the furosemide group (44.2% vs. 20.4%, p=0.0123). The proportion of neurons inhibited by application of losartan was enhanced, (26.4% vs. 9.3%, p=0.03). No significant changes were found in response to PD123319 by itself. Moreover, there were more neurons which co-localized responses to both Los and PD123319 in the furosemide group than in the control group (29.7% vs. 8.6%, p=0.027). It is known that multidepletions induce an increased need-free sodium appetite and our present findings could well form part of the neuronal basis of this behavior.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aldosterone / pharmacology*
  • Angiotensin II / pharmacology*
  • Angiotensins
  • Animals
  • Imidazoles / pharmacology
  • Losartan / pharmacology
  • Male
  • Neurons / drug effects*
  • Neurons / metabolism
  • Preoptic Area / cytology
  • Preoptic Area / drug effects*
  • Preoptic Area / metabolism
  • Pyridines / pharmacology
  • Rats
  • Rats, Wistar
  • Septum Pellucidum / cytology
  • Septum Pellucidum / drug effects*
  • Septum Pellucidum / metabolism
  • Sodium / metabolism*

Substances

  • Angiotensins
  • Imidazoles
  • Pyridines
  • Angiotensin II
  • PD 123319
  • Aldosterone
  • Sodium
  • Losartan