Objective To demonstrate the presence of adrenomedullin in the central nervous system.Methods Using immunohistochemical method (ABC) and reverse transcription-polymerase chain reaction (RT-PCR) analysis, the distribution of immunoreactive (IR-) AdM and AdM mRNA was observed in the rat and the human brain.Results Immunoreactive(IR-) AdM and AdM mRNA were detectable in almost every region of the rat brain examined, including cerebral cortex, paraventricular tissues, hypothalamus, mesencephalon, medulla oblongata and cerebellum. The levels of AdM mRNA in paraventricular tissues and medulla oblongata were higher than those in the other brain regions. AdM mRNA was also detectable in the human brain. Conclusion The present study shows that AdM is present in the central nervous system, suggesting that AdM might act as a neurotransmitter, neuromodulator or neurohormone in rats or humans.