The type-1 cannabinoid receptor modulates the hydroelectrolytic balance independently of the energy homeostasis during salt load

Author(s)

Vechiato, F. M. V. ^[1] ; Rivas, P. M. S. ^[1] ; Ruginsk, S. G. ^{[2, 1]} ; Borges, B. C. ^[1] ; Elias, L. L. K. ^[1] ; Antunes-Rodrigues, J. ^[1]

Affiliation

^[1] Univ Sao Paulo, Dept Physiol, Sch Med Ribeirao Preto, BR-14049900 Sao Paulo - Brazil

^[2] Univ Fed Alfenas, Inst Biomed Sci, Dept Physiol Sci, BR-37130000 Alfenas, MG - Brazil

• Document type: Journal article
• Source: Hormones and Behavior; v. 78, p. 43-51, FEB 2016.
• Web of Science Citations: 1

Abstract

Hydroelectrolytic imbalances, such as saline load (SL), trigger behavioral and neuroendocrine responses, such as thirst, hypophagia, vasopressin (AVP) and oxytocin (OT) release and hypothalamus-pituitary-adrenal (HPA) axis activation. To investigate the participation of the type-1 cannabinoid receptor (CB1R) in these homeostatic mechanisms, male adult Wistar rats were subjected to SL (0.3 M NaCl) for four days. SL induced not only increases in the water intake and plasma levels of AVP, OT and corticosterone, as previously described, but also increases in CB1R expression in the lamina terminalis, which integrates sensory afferents, as well as in the hypothalamus, the main integrative and effector area controlling hydroelectrolytic homeostasis. A more detailed analysis revealed that CB1R-positive terminals are in close apposition with not only axons but also dendrites and secretory granules of magnocellular neurons, particularly vasopressinergic cells. In satiated and euhydrated animals, the intra-cerebroventricular administration of the CB1R selective agonist ACEA (0.1 mu g/5 mu L) promoted hyperphagia, but this treatment did not reverse the hyperosmolality-induced hypophagia in the SL group. Furthermore, ACEA pretreatment potentiated water intake in the SL animals during rehydration as well as enhanced the corticosterone release and prevented the increase in AVP and OT secretion induced by SL. The same parameters were not changed by ACEA in the animals whose daily food intake was matched to that of the SL group (Pair-Fed). These data indicate that CB1Rs modulate the hydroelectrolytic balance independently of the food intake during sustained hyperosmolality and hypovolemia. (C) 2015 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 13/09799-1 - Energy balance and body fluid homeostasis control: from cells to the physiological systems
• Grantee: José Antunes Rodrigues
• Support Opportunities: Research Projects - Thematic Grants