Regulation of Dopamine in a Rat Limbic Brain Region in Response to Aversive Stimulus
Jin W. Park, Lingbo Lu, Jinwoo Park
Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, New York 14214, USA
Dopamine in the limbic forebrain structures such as the nucleus of accumbens (NAc) known as a modulator for emotional states, learning, and drug abuse, integrates sensory information and initiates the subsequent behavioral and physiological responses in response to environmental stimuli such as sound and light. It is known that chronic exposure of loud noise as a stressor can lead to both psychological and physiological disorders such as hearing loss, depression and attention deficit hyperactivity disorder. Here, we investigated the functional relationship between the dopamine signaling in the NAc and the aversive stimulus, noise. For this study, fast-scan cyclic voltammetry (FSCV) coupled with carbon fiber microelectrodes (CFE) was used to examine the rapid changes of the extracellular dopamine concentration in the NAcof freely moving rats before, during acute aversive stimuli (10 s, 60-100 dB) and after the termination of that stimulus. Dopamine signaling in the NAc in response to the aversive stimuli was shown to be more heterogeneous. Throughout the duration of the stimuli, dopamine transmission was inhibited. At the cessation of the stimuli, however, extracellular dopamine concentration was back to or sharply increased above the basal pre-dopamine level. This result suggests that dopamine is one of the key neurotransmitter to integrative processing of the aversive sensory inputs which can influence behavioral outputs appropriate for adaptation and survival.