Chapter 31 Significance of opioid peptides and other potential markers of neuropeptide systems in cerebrospinal fluid

Abstract

Publisher Summary This chapter discusses the significance of opioid peptides and other potential markers of neuropeptide systems in cerebrospinal fluid (CSF). The CSF is in constant exchange with the extracellular fluid of the central nervous system (CNS). Substances released from central neurons and escaping metabolic breakdown will therefore appear in CSF. Formation of a particular peptide is a process occurring in consecutive steps, and depending on the rate of formation, the level and relative proportion of different peptides from the same system varies. It is assumed that the CSF level depends on the (a) rate of formation, (b) rate of release, (c) rate of dilution, and (d) metabolism in the CSF compartment itself. The rate of formation of the neuropeptide in the nerve terminal defines the products available for release. The acute effects of low-frequency transcutaneous nerve stimulation (TENS) on the release of opioid peptides measured by receptor assay have been studied. The chapter discusses whether the activity in peptidergic pathways can be assessed by analyzing the content of neuropeptides, and other potential markers of neuropeptide systems, in the CSF.