In this thesis, rodent models of chronic pain were used to explore analgesic mechanisms that may potentially be engaged in spinal and peripheral compartments by systemically-administered amitriptyline, a tricyclic antidepressant. The first project (Chapter 2) identified the roles of spinal adenosine A1 and serotonin 5-HT7 receptors, as well as of peripheral adenosine A1 receptors, in the acute antinociceptive effects of amitriptyline in mice. The second project (Chapter 3) examined the potential utility of amitriptyline as a preventive analgesic against persistent post-surgical pain, and involved perioperative administration of amitriptyline after peripheral nerve injury in rats. Changes in post-injury behavioural outcomes, as well as spinal noradrenergic sprouting, were assessed. Overall, spinal serotonergic pathways linked to adenosine A1 receptors, as well as peripheral adenosine A1 receptors, appear to be important in antinociception by amitriptyline. Preventive analgesia by this drug does not appear to result from anatomical changes in spinal noradrenergic pathways.

G protein-coupled receptors (GPCRs) are eukaryotic integral membrane proteins that perform transmembrane signal transduction. Due to their pivotal role in a wide range of essential physiological functions GPCRs represent a high proportion of all drug targets. High resolution X-ray structures of GPCRs are however underrepresented in the Protein Data Bank. This is due to their instability in detergent, low expression levels and the presence of misfolded receptors in many heterologous expression systems. The objective of this project was to engineer the angiotensin II type 1 receptor (AT1R), a human GPCR, to make it suitable for structural studies. It was determined that detergentsolubilised AT1R was thermostable with antagonist bound with an apparent Tm of ~45°C, which was sufficiently stable for purification without further thermostabilisation by rational mutagenesis. Two expression systems were then evaluated for large-scale production of AT1R, namely baculovirus-mediated expression in insect cells and mammalian expression in HEK293 cells. Radioligand binding assays showed that only the mammalian system produced sufficient quantities of active AT1R for structural studies. Expression in the mammalian system was further optimised to approximately 6 mg/L. An AT1R-GFP fusion was created to examine membrane localisation using confocal laser scanning microscopy, to assay expression levels, to select highly expressing monoclonal cell lines using fluorescence activated flow cytometry and to develop a fluorescence size-exclusion chromatographybased assay to examine the suitability of 12 different ligands for co-crystallization. AT1R was also engineered to facilitate crystallisation, including C-terminal truncations to remove predicted disordered regions and bacteriophage T4-lysozyme being added to the third intracellular loop to provide additional points of contact for crystallisation, which increased the apparent Tm by approximately 10°C. All modified versions of AT1R were assessed for expression, stability and monodispersity. Additionally a rapid western blotting based assay was developed for the detection of unfolded membrane proteins, which will have wide applicability in the field.

Severe perinatal hypoxia represents a substantial brain injury in human newborns. This Diploma thesis is focused on long-term motor outcome of laboratory rat after moderate perinatal hypoxia. We described some behavioral test for detection motor development and presented the influence of perinatal hypoxia on central nervous system. We also discussed an effect of agonists and antagonists of adenosine A1 receptor in brain. The aim of an experimental part was an evaluation of long-term motor behavior in rats affected by perinatal hypoxia. To cause perinatal hypoxia we put pregnant female rats to a hypoxic (10% O2) normobaric room in 11th day of their gestation. The pregnant female rats stayed in hypoxic room until they gave a birth and 6 more days after birth with their litters. For classification of motor development we used battery of tests of motor coordination. These tests correspond to the level of development of the rat. Then a group of rats with perinatal hypoxia was treated by a single administration of an agonist of adenosine A1 receptor 2-chloro-N(6)- cyclopentyladenosin (CCPA) in postnatal day 14. The animals affected by perinatal hypoxia show motor deficits in 3 from 4 selected behavioral tests. Otherwise, this motor behavior was no longer detected in young adults. The rats affected by...