Participation of the serotonergic system in the regulation of water and electrolyte balance

ABSTRACT

To determine the possible participation of the serotonergic (5-Ht system in the regulation of water and electrolyte balance, rats were submitted to two sessions of water overloading and the 5-HT agonist MK 212 was administered intracerebroventricularly (icv) in 1.0 micronl 20 min after the second session. Urine volume and sodium and potassium excretion were measured over a priod of 120 min. Microinjection of MK-212 (1 microng/animal) caused a significant reduction (24 to 57%; mean, 43%) in natriuresis throghout the experimental period, and the administration of 10 microng/animal caused a 26-41% reduction (mean, 33%) in kaliuresis. At 20 microng/ animal, MK-212 did not change any of the parameters investigated. No significant change in urine volume was detected after any of the reatments used