ADRENALINE - CRYPTIC CENTRAL CATECHOLAMINE

Adrenaline is a biogenic amine present in the central nervous system at concentrations which represent less than 5% of noradrenaline levels. Although established as a hormone released from the adrenal medulla, attempts to demonstrate a role as a transmitter in brain have been frustrated by the extremely low levels. The adrenaline-synthesizing enzyme, phenylethanolamine-N-methyltransferase, has now been localized in discrete neurones, particularly in the medulla oblongata. Recent evidence suggests adrenaline is involved in the central regulation of blood pressure. With the advent of drugs acting on adrenergic mechanisms, this catecholamine should soon be proven a transmitter in the central nervous system. © 1979.