Maternal caffeine intake has minor effects on adenosine receptor ontogeny in the rat brain

Maternal caffeine intake has been suggested to influence the offspring. We have studied the effects of maternal caffeine intake on adenosine and GABA receptors, targets for caffeine, during development of the rat brain. Caffeine (0.3 gn) was added to the drinking water of rat darns during pregnancy and early postnatal life. Adenosine A(1) and A(2A) and GABA(A) receptor development was studied using receptor autoradiography and in situ hybridization. Pups were examined on embryonic d 14 (E14), E18, E21, 2 h after birth (P2h), P24h, postnatal d 3 (P3), P7, P14, and P21. Adenosine A(1) receptor mRNA was detected at E14 and receptors at E18. A(1) mRNA levels increased from the level reached at E18 between P3 and P14 (maximally a doubling), whereas A(1) receptors, studied by [H-3]-1,3-dipropyl-8-cyclopentyl xanthine binding, increased later and to a much larger extent (about 10-fold) postnatally. Caffeine treatment had no significant effect on adenosine A(1) receptors or on A(1) receptor mRNA. A(2A) mRNA had reached adult levels by E18, whereas receptor levels were low or undetectable before birth and increased dramatically until P14. Caffeine did not influence A(2A) receptors or A(2A) receptor mRNA at any stage during development. [3(H)]-flunitrazepam binding, representing GABA(A) receptors, showed large regional variations during ontogeny, but there were no clear differences between the caffeine-exposed and the nonexposed pups. Thus, exposure to a low dose of caffeine during gestation and postnatal life had only minor effects on development of adenosine A(1) and A(2A) receptors and GABA(A) receptors in the rat brain.