Adrenergic regulation of haematopoiesis.

In spite of many reports demonstrating the presence of sympathetic fibres innervating the bone marrow, the evidence for a direct adrenergic influence on haematopoiesis is a recent finding. This review concentrates on recent work on the role of adrenergic agents in haematopoiesis. In particular, alpha-adrenergic antagonists may greatly augment myelopoiesis and platelets production while decreasing lymphopoiesis either after bone marrow transplantation or in normal mice. On the other hand, adrenergic agonists seem to exert an inhibitory effect on myelopoiesis. Of clinical relevance, the sympathetic neurotransmitter noradrenaline can rescue the blood forming system and improve the survival of mice injected with a lethal dose of carboplatin or exposed to X-ray irradiation. Apparently, noradrenaline acts via alpha 1-adrenergic receptors present in pre-B cells. Activation of such receptors seems to induce the production of transforming growth factor-beta which mediates the haematopoietic effects. These findings seems relevant to our understanding of the physiopathology of haematopoiesis and may open new possibilities for treating haematological disorders and in the clinical management of anticancer myeloablative treatments.