Centrally-Mediated Effects of Prostaglandin A2 on Urine Outflow.

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Abstract
Intracerebroventricular (i.c.v.) injections to rats of saline and 6% ethanol at a volume of 10 .mu.l were given to ensure that experimental procedures had no effect on urine outflow. When PG[prostaglandin]A2 at a dose of 10 nmol in 10 .mu.l was injected i.c.v., urine outflow increased in 15 out of 26 rats and decreased in the remaining animals. The extent to which 10 nmol of PGA2 produced effects was not significantly different from that produced by 20 nmol of PGA2. PGA2 (5 nmol) was without effect on urine outflow. Both of these effects were central in origin, since neither the diuretic nor antidiuretic effects were produced by i.v. injection of PGA2 at the same doses as injected i.c.v. PGA2 produced effects without altering blood pressure. PGA2 injected i.c.v. may function, at least in part, by controlling release of ADH [antidiuretic hormone] from the hypothalamo-neurohypophysial system. The appearance of these opposite effects was animal-dependent, and indeed 1 animal showed the same response to repeated experiments. There may be 2 quite different kinds of action-sites for PGA2 which are characteristic of an individual rat.