Effect of the intracerebroventricular administration of GR 113808, a selective 5-HT4 antagonist, on water intake during hyperosmolarity and hypovolemia

L. Castro, B. Varjão, I. Silva, B. Duque, A. Batista, R. Santana, P. Luz, M.A. Rocha Junior, J.B. Fregoneze, E. De Castro-e-Silva
2001 Brazilian Journal of Medical and Biological Research  
We demonstrate here that acute third ventricle injections of GR 113808, a highly selective 5-HT 4 antagonist, decrease water intake induced by a previous salt load while potentiating drinking elicited by hypovolemia induced by previous subcutaneous administration of polyethylene glycol in male Wistar rats (200 ± 20 g). At the dose of 160 nmol/rat, third ventricle injections of GR 113808 induced a significant reduction of water intake in salt-loaded animals after 120 min as compared to
more » ... mpared to salt-loaded animals receiving third ventricle injections of saline (salt load + GR = 3.44 ± 0.41 ml, N = 12; salt load + saline = 5.74 ± 0.40 ml, N = 9). At the dose of 80 nmol/rat, GR 113808 significantly enhanced water intake in hypovolemic animals after 120 min as compared to hypovolemic animals receiving third ventricle injections of saline (hypovol + GR = 4.01 ± 0.27 ml, N = 8; hypovol + saline = 2.41 ± 0.23 ml, N = 12). We suggest that central 5-HT 4 receptors may exert a positive drive on water intake due to hyperosmolarity and a negative input on drinking provoked by hypovolemia.
doi:10.1590/s0100-879x2001000600015 pmid:11378670 fatcat:ovgixemtc5hsjfi5rmfhznmkoq