Correlation of the Amounts of Plasma Dopamine Among Dogs with Different Types of Aggression

Abstract

The purpose of this study was to determine whether a link existed between the amounts of plasma dopamine (DAp) and aggressive behavior in canine patients. For such purpose, we worked with two groups: one group of fifteen male, non-castrated, mostly adult dogs with no signs of disease and diagnosed as aggressive through the application of an ethological protocol; and another group of five dogs (control group) with the same characteristics as the group under study, except without the behavioral problems. Individual, environmental and behavioral characteristics associated to the DAp concentrations through the high performance liquid chromatography (HPLC), coupled to an electrochemical detector, were determined for each group. The results from the group under study revealed mostly dominance (73%), intraspecific (14%) and territorial (13%) aggression, and signs of anxiety were also detected in 73% of them. Regarding DAp values, 53% of the dogs obtained values below 0.04 ng/ml, while it was not possible to determine an average value for the remaining 47%, due to the extent of their distribution. DAp values for the control group were less than 0.04 ng/ml. Through an ANDEVA of least squares means, it was determined that 64% of the plasma concentrations of DA were explained by anxiety, which was not the case for aggressive behaviors.