Somastatin receptors in the hematopoietic system

Multiple interactions exist between the immune, hematopoietic, endocrine and nervous systems [1,2]. The bi-directional communication between the immune/hematopoietic and nervous systems is mediated by complex mechanisms involving multiple soluble factors (e.g., neuropeptides, neurotrophic factors, neurotransmitters and cytokines) produced by each system [3-5]. Examples of such factors are the neurotransmitter neuropeptide Y [6], produced by megakaryocytes [7], substance P (SP), which enhances the proliferation of primitive bone marrow cells and progenitors [4] and nerve growth factor (NGF), which contributes to differentiation of human basophils [8] and stimulates the release of inflammatory mediators from these cells [9]. A number of studies have demonstrated the expression of somatostatin receptors on cells derived from several hematological malignancies and have shown that somatostatin inhibits proliferation of these cells [1 0]. However, little is known of the effects of somatostatin on normal blood cell formation (hematopoiesis). This thesis comprises studies dealing with the role of somatostatin, a neuropeptide with multiple functions in the body, in hematopoiesis