ABSTRACT
Anabolic androgenic steroids (AAS) abuse is becoming increasingly common and may result in a range of physical as well as psychiatric effects, such as altered behavior in terms of increased aggression, cognitive dysfunction, and addictive behavior. AAS comprise testosterone and its derivatives, of which nandrolone is very common. Studies have shown the nandrolone-induced effects in male rats at various neuropeptide levels in several areas of the central nervous system (CNS). Effects of nandrolone on the dynorphinergic systems may be linked to some of the reported behavior alterations. This chapter is aimed to review mechanisms underlying alterations in the dynorphin system and also to describe effects attributed to nandrolone administration on its selective receptor, the κ-opioid peptide (KOP) receptor. The results display signicant effects on the enzymatic
9.1 Introduction .................................................................................................. 149 9.2 Anabolic Androgenic Steroids ...................................................................... 150
9.2.1 Denition ......................................................................................... 150 9.2.2 Use in Society ................................................................................... 150 9.2.3 Administration Patterns .................................................................... 151 9.2.4 Psychological Aspects ...................................................................... 152 9.2.5 Pharmacological Aspects ................................................................. 153
9.3 The Dynorphinergic System ......................................................................... 154 9.4 Effects of AAS on the Dynorphinergic System and Cognitive Functions ...... 156 Acknowledgments .................................................................................................. 158 References .............................................................................................................. 158
conversion of dynorpin A into its bioactive metabolite, Leu-enkephalin-Arg6, as a result of nandrolone treatment (Figure 9.1). More profound investigations on the dynorphinergic system displayed effects on the KOP receptor density in various brain regions. Studies have also conrmed a signicant increase in the expression of the gene transcript of the dynorphinergic precursor, prodynorphin (PDYN), in the hippocampus-the region of the brain associated with cognitive processes. In addition, in studies of male rats, impaired spatial learning and memory as recorded in the Morris water maze (MWM) task following nandrolone administration has also been encountered. Thus, reviewed data strengthen the role of the dynorphin system in mechanisms underlying behavioral effects seen in individuals taking AAS.
