Chapter 10 The role of nitric oxide in motility of the developing gastrointestinal tract

Abstract

Publisher Summary This chapter provides an overview of the functions of nitric oxide (NO) in the gastrointestinal tract (GIT) in adult and developing animals and humans. NO is produced by nitric oxide synthase (NOS) and by nonenzymatic pathways. In the gastrointestinal tract (GIT) of adults, the majority of NO-producing neurons are localized in the myenteric plexus where they act as inhibitory inter and motoneurons. NO plays a role as a neurotransmitter in the enteric nervous system (ENS). NO is involved in non-adrenergic, non-cholinergic (NANC) inhibitory neurotransmission in the GIT. The nitrergic innervation is important for the growth, maturation, and proper function of the GIT as the inhibition of cNOS causes severe impairment of gastrointestinal function. The occurrence of NOS-positive cells in a variety of organs (CNS, respiratory system, and GIT) is higher at the prenatal stage of development than at other times suggesting that NO is also important for the development of these organs in addition to its importance for foetal and postnatal development of the mammalian GIT. The distribution of nitrergic neurons in the GIT in fetuses, growing and adult animals, and humans is discussed. The chapter reviews interstitial cells of Cajal (ICC) that refer to the connection of ICC with nitrergic neurons, the involvement of ICC in NO production, and neurotransmission involving nitrergic neurons. The actions of NO and the distribution of nitrergic neurons in the GIT of growing animals is presented, and some other aspects of the role of NO in the development of the GIT are discussed.