EXPRESSION OF PITUITARY ADENYLATE-CYCLASE ACTIVATING POLYPEPTIDE RECEPTORS IN THE EARLY MOUSE EMBRYO AS ASSESSED BY REVERSE TRANSCRIPTION-POLYMERASE CHAIN-REACTION AND IN-SITU HYBRIDIZATION

We have examined the expression of mRNA for the pituitary adenylate cy clase activating polypeptide (PACAP) receptor in the mouse from day 9. 5 of embryonic development onwards by reverse transcription polymerase chain reaction (RT-PCR) and by in situ hybridisation. PACAP receptor mRNAs were detected by PCR in the earliest developmental stage examine d and thereafter the levels of mRNA for all receptors increased during development. Wholemount in situ hybridisation first showed the expres sion of the PACAP receptor in the neural tube of 9.5 day old embryos, in later embryos heaviest expression of the PACAP receptor was found i n the developing rhombencephalon (day 10.5 and 11.5). These results ar e consistent with a role for PACAP or a related peptide in the early d evelopment of the central nervous system.