Even though caffeine can be excreted in breast milk, few studies have analyzed the effect of maternal caffeine consumption during lactation on neonatal brain. In the present work pregnant rats were treated daily with 1 g/L of caffeine in their drinking water during pregnancy and/or lactation and the effect on adenosine A(1) receptor in brains from both lactating mothers and 15 days-old neonates was assayed using radioligand binding and real time PCR assays. Mothers receiving caffeine during gestational period developed motor activation in gestational days 8-10 which was associated with a significant decrease of total adenosine A(1) receptor number (84%). A similar decrease was detected in mothers treated with caffeine during lactation (76%) and throughout gestation and lactation (73%); this was accompanied by a significant decrease in mRNA level coding adenosine A(1) receptor (28%). In male neonates, adenosine A(1) receptor was also decreased after chronic caffeine exposure during gestation (80%), lactation (76%) and gestation plus lactation (80%). In female neonates, adenosine A(1) receptor tended to decrease in response to caffeine exposure although no significant variations were found. No variation in the level of mRNA coding adenosine A(1) receptor was detected in neonates in any case. Concerning adenosine A(2A) receptor, radioligand binding assays revealed that this receptor remains unaltered in maternal and neonatal brain in response to caffeine exposure. However, caffeine consumption during gestation and lactation evoked a significant decrease in mRNA level coding A(2A) receptor (32%) in mothers' brain.
(c) 2009 Wiley-Liss, Inc.