Mineral preference in rats treated with muscimol into the lateral parabrachial nucleus

• Published in: Neuroscience letters 2020-07, Vol.731, p.134989-134989, Article 134989
• Main Authors: Callera, João Carlos, De Luca, Laurival Antonio, Menani, José Vanderlei
• Format: Article
• Language: English
• Subjects: Animals; Bicarbonate; Dehydration; Fluid intake; GABA; GABA Agonists - pharmacology; GABA Antagonists - pharmacology; GABA-A Receptor Agonists - pharmacology; Male; Minerals - metabolism; Minerals - pharmacology; Muscimol - pharmacology; Parabrachial nucleus; Parabrachial Nucleus - drug effects; Parabrachial Nucleus - physiology; Rats, Wistar; Receptors; Receptors, GABA-A - drug effects; Receptors, GABA-A - metabolism; Sodium - metabolism; Sodium appetite; Sodium Chloride - pharmacology
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2020.134989

•Muscimol into the lateral parabrachial of hydrated rats produces hypertonic salt intake•Such an effect of muscimol was selective to 0.3 M NaCl versus water, and K and Ca solutions•It also induced 0.3 M NaHCO3 intake and resisted cell-dehydration•The lateral parabrachial checks selectively hypertonic sodium intake Injection of muscimol, a GABAA receptor agonist, into the lateral parabrachial nucleus (LPBN) induces 0.3 M NaCl intake in rats. In the present work, we investigated whether such an effect applies to hypertonic (0.3 M) mineral solutions in general or is selective to sodium solutions in a 240 min intake test. Muscimol injection (0.5 nmol/0.2 μL) compared to vehicle injection into the LPBN of adult hydrated rats produced a preferential ingestion of 0.3 M NaCl (25.3 ± 10.2 mL) followed by a 0.3 M NaHCO3 intake (11.7 ± 5.6 mL), with no significant effect on water, KCl and CaCl2 intake. Only the effect of muscimol on NaCl intake (19.0 ± 10.4 mL) persisted in cell-dehydrated rats, with hardly any effect on water or other mineral solutions. The results suggest that the LPBN controls the ingestion of hypertonic NaCl and NaHCO3. They also suggest a selective mechanisms involving the LPBN to check hypertonic sodium intake.