Gastric myoelectrical activity as an index of emotional arousal.

Autonomic nervous system parameters such as electrodermal activity, heart rate, and facial EMG have been utilized extensively as measures of emotional arousal. One measure that has rarely been employed in this setting is gastric myoelectrical activity, despite the fact that "gut feelings" have an obvious and even profound role in everyday emotional life. It has been shown that the gastrointestinal system changes wall tonus and contraction rate during stressful tasks. However, the effects of emotionally salient stimuli on gastrointestinal motility have scarcely been studied. In the current study, emotional film clips designed to elicit happiness, disgust, fear, sadness, or no emotion (neutral) were presented to 16 normal participants. Electrogastrogram (EGG), skin conductance, and heart rate were measured while the participants viewed the film clips, and participants rated subjective arousal intensity and pleasantness of the film clips. We found that emotional film clips reliably induced the intended subjective feeling states. Also, EGG peak amplitudes in fear, disgust, sadness and happiness were higher than in the no emotion condition. There was a strong positive correlation (r=0.64) between EGG peak amplitude and subjective ratings of arousal. This is the first evidence that gastric myoelectrical activity is strongly correlated with arousal ratings to emotionally salient stimuli, and it suggests that EGG may add useful information about how the body contributes to the phenomenology of emotion and feeling.

Evidence that ATP participates in the pathophysiology of pilocarpine-induced temporal lobe epilepsy: fluorimetric, immunohistochemical, and Western blot studies.

PURPOSE: This study was performed to study the role of adenosine triphosphate (ATP) in the brain of pilocarpine-induced chronic epileptic rats. METHODS: ATP-mediated changes in intracellular calcium were studied by the fura-2 method. Immunohistochemistry and Western blotting methods were used to localize and quantify P2X7 receptors in these animals. RESULTS: The fluorimetric study in chronic rats revealed a biphasic response indicating the presence of P2X7 receptors. The Western blotting study showed an increase of 80% of P2X7 expression in chronic rats compared with the control group. P2X7 immunoreactivity resembled mossy fiber sprouting at the dentate gyrus of epileptic animals. CONCLUSIONS: These results suggest that purinergic receptors may participate in the pathophysiology of temporal lobe epilepsy.