We studied the reaction mechanism of dopamine autoxidation using quantum chemical methods. Unlike other biogenic amines important in the central nervous system, dopamine and noradrenaline are capable of undergoing a non-enzymatic autoxidative reaction giving rise to a superoxide anion that further decomposes to reactive oxygen species. The reaction in question, which takes place in an aqueous solution, is as such not limited to the mitochondrial membrane where scavenging enzymes such as catalase and superoxide dismutase are located. With the experimental rate constant of 0.147 s−1, the dopamine autoxidation reaction is comparably as fast as the monoamine oxidase B catalyzed dopamine decomposition with a rate constant of 1 s−1. By using quantum chemical calculations, we demonstrated that the rate-limiting step is the formation of a hydroxide ion from a water molecule, which attacks the amino group that enters intramolecular Michael addition, giving rise to a pharmacologically inert aminochrome. We have shown that for dopamine stability on a time scale of days, it is essential that the pH value of the synaptic vesicle interior is acidic. The pathophysiologic correlates of the results are discussed in the context of Parkinson's disease as well as the pathology caused by long-term amphetamine and cocaine administration.

This study showed the feasibility and efficacy of intraarticular patient-controlled regional analgesia technique for pain relief after anterior cruciate ligament reconstruction. The combination of intraarticular ropivacaine, morphine, and ketorolac was superior to control or to a combination of ropivacaine and morphine.

P Pu ur rp po os se e: : To evaluate the safety and applicability of two local anesthetic (LA) solutions self-administered for pain treatment after inguinal hernia repair (IHR) by balloon-pumps via catheters placed in the surgical wound. Effectiveness of analgesia was also compared.

BackgroundDepression, anxiety and chronic pain are frequent co-occurrent disorders. Patients with these mental disorders experience more intense pain that lasts for a longer time.MethodQuestionnaire with 228 variables was applied to 109 randomly chosen patients that were treated at an outpatient clinic for treatment of chronic pain of the University Clinical Centre Ljubljana from March to June 2013. 87 patients responded to the questionnaire (79.8%). Location of pain considering diagnosis was the criterion in the discriminant analysis (soft tissue disorders; headache; symptoms not elsewhere classified; back pain) and following summative scores as predictors: level of depression and anxiety (The Zung Self-Rating Depression/Anxiety Scale), evaluation of pain and perceptions of being threatened in social relations.ResultsAverage age of participants was M = 52.7 years (SD 13.9), with 70.9% female, 29.1% male participants. 63% of respondents achieved clinically important level of depression and 54% clinically important level of anxiety. On univariate level, the highest level of depression and anxiety was found for back pain and the lowest for headache. No significant difference was found in evaluation of pain and perceptions of being threatened in social relations regarding location of pain. Self-evaluation of depression has, in the framework of discriminant analysis, the largest weight for prediction of differentiation between different locations of pain.ConclusionDifferent locations of pain have different connections with mood levels. The results of research on a preliminary level indicate the need to consider mental experience in the treatment of chronic pain.