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. Caffe ine (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 dev elopment was studied using receptor autoradiography and in situ hybridizati on. 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 m RNA was detected at E14 and receptors at E18. A(1) mRNA levels increased fr om the level reached at E18 between P3 and P14 (maximally a doubling), wher eas A(1) receptors, studied by [H-3]-1,3-dipropyl-8-cyclopentyl xanthine bi nding, increased later and to a much larger extent (about 10-fold) postnata lly. Caffeine treatment had no significant effect on adenosine A(1) recepto rs or on A(1) receptor mRNA. A(2A) mRNA had reached adult levels by E18, wh ereas receptor levels were low or undetectable before birth and increased d ramatically 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 o ntogeny, but there were no clear differences between the caffeine-exposed a nd the nonexposed pups. Thus, exposure to a low dose of caffeine during ges tation and postnatal life had only minor effects on development of adenosin e A(1) and A(2A) receptors and GABA(A) receptors in the rat brain.