Lactate inhibited sodium intake in dehydrated rats. (1st August 2022)

• Record Type: Journal Article
• Authors: Fernandes-Costa, Francineide; de Lima Flôr, Atalia Ferreira; de Andrade Braga, Valdir; Campos Cruz, Josiane
• Is Part Of: Appetite. Volume 175(2022)
• Publication Date: 2022-08-01
• Subjects: Water deprivation -- Thirst -- Sodium avoidance -- Lactate -- MCT; Food habits -- Periodicals; Appetite -- Periodicals; Appetite disorders -- Periodicals; Electronic journals; 306.4613
• DOI: 10.1016/j.appet.2022.106046
• Languages: English
• ISSNs: 0195-6663

Abstract

Abstract: Recent studies have suggested that glial cells, especially astrocytes, are involved in balanced hydromineral modulation. In response to increased extracellular Na + concentration, astrocytic Nax channels are activated, promoting lactate production and release. Furthermore, previous in vitro studies have suggested that lactate and hypertonic Na + solution activate SFO GABAergic neurons involved in the salt-appetite central pathways. Here, we evaluated the role of lactate in dehydration-induced sodium and water intake. To this end, intracerebroventricular microinjection (icv) of l -lactate or α-cyano-4-hydroxycinnamic acid (α-CHCA, MCT lactate transporter inhibitor) was performed in rats subjected to 48 h of water deprivation (WD) and 1 h of partial rehydration after 48 h of WD (WD-PR). The rehydration protocol was used to distinguish the mechanisms of thirst and sodium appetite induced by WD. Then, water and sodium (0.3 M NaCl) intake were evaluated for 2 h. Our results showed that central α-CHCA induced an increase in sodium preference in WD rats. Furthermore, central lactate increased water intake but reduced sodium intake in WD-PR animals. In contrast, central lactate transporter inhibition did not change water or sodium intake in WD-PR rats. Our results suggest that lactate is involved in inhibitory mechanisms that induce sodium intake avoidance in dehydrated rats.