Moxonidine into the lateral parabrachial nucleus modifies postingestive signals involved in sodium intake control

Neuroscience. 2015 Jan 22;284:768-774. doi: 10.1016/j.neuroscience.2014.09.042. Epub 2014 Sep 28.

Abstract

The activation of α2-adrenoceptors with bilateral injections of moxonidine (α2-adrenoceptor and imidazoline receptor agonist) into the lateral parabrachial nucleus (LPBN) increases 1.8% NaCl intake induced by treatment with furosemide (FURO)+captopril (CAP) subcutaneously. In the present study, we analyzed licking microstructure during water and 1.8% NaCl intake to investigate the changes in orosensory and postingestive signals produced by moxonidine injected into the LPBN. Male Sprague-Dawley rats were treated with FURO+CAP combined with bilateral injections of vehicle or moxonidine (0.5 nmol/0.2 μl) into the LPBN. Bilateral injections of moxonidine into the LPBN increased FURO+CAP-induced 1.8% NaCl intake, without changing water intake. Microstructural analysis of licking behavior found that this increase in NaCl intake was a function of increased number of licking bursts from 15 to 75 min of the test (maximum of 49±9 bursts/bin, vs. vehicle: 2±2 bursts/bin). Analysis of the first 15 min of the test, when most of the licking behavior occurred, found no effect of moxonidine on the number of licks/burst for sodium intake (24±5 licks/burst, vs. vehicle: 27±8 licks/burst). This finding suggests that activation of α2-adrenoceptors in the LPBN affects postingestive signals that are important to inhibit and limit sodium intake by FURO+CAP-treated rats.

Keywords: parabrachial nucleus; postingestive; sodium intake; α(2)-adrenoreceptors.

MeSH terms

  • Adrenergic alpha-2 Receptor Agonists / pharmacology*
  • Animals
  • Captopril / pharmacology
  • Catheters, Indwelling
  • Diuretics / pharmacology
  • Drinking / drug effects*
  • Drinking / physiology
  • Drinking Behavior / drug effects*
  • Drinking Behavior / physiology
  • Drinking Water / administration & dosage
  • Furosemide / pharmacology
  • Imidazoles / pharmacology*
  • Imidazoline Receptors / agonists
  • Imidazoline Receptors / metabolism
  • Male
  • Parabrachial Nucleus / drug effects*
  • Parabrachial Nucleus / metabolism
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, alpha-2 / metabolism
  • Sodium Chloride* / administration & dosage

Substances

  • Adrenergic alpha-2 Receptor Agonists
  • Diuretics
  • Drinking Water
  • Imidazoles
  • Imidazoline Receptors
  • Receptors, Adrenergic, alpha-2
  • Sodium Chloride
  • Furosemide
  • Captopril
  • moxonidine