Habituation and Sensitization Processes in Depressive Disorders
The aim of the present study was to investigate further into habituation and sensitization processes in depressive disorders. The depressive subjects were 27 outpatients. All of them were diagnosed according to DSM-III-R criteria. Controls were 27 normal subjects. The amplitudes of electrodermal responses and the basal levels were recorded during a stimuli series of 15 80-dB tones and of 1 100-dB tone in the 11th trial. The depressive patients displayed lower basal conductance levels and lower conductance amplitudes in orienting responses to the first stimulus and to stimulus change. No differences were found in conductance response amplitudes of stimuli series, although a tendency towards …
Hippocampal dopamine receptors modulate the motor activation and the increase in dopamine levels in the rat nucleus accumbens evoked by chemical stimulation of the ventral hippocampus.
A number of studies have shown that chemical stimulation (using N-methyl-D-aspartate (NMDA) infusions) or electrical stimulation of the ventral hippocampus (VH) elicits locomotor activation and sustained increases in nucleus accumbens (NAc) dopamine (DA) levels in rodents. How DA neurotransmission in NAc is involved in these effects has also been well established. However, the modulatory role of the DA receptors located in VH is not yet fully understood. The purpose of this study was to characterize the role played by VH D1 and D2 subtype receptors in both the locomotor activation and NAc DA increases induced by NMDA stimulation of the VH. This was assessed by studying how retrodialysis app…
Ascorbic acid antagonizes ethanol-induced locomotor activity in the open-field.
Abstract It has been reported that ascorbic acid (AA) antagonizes the physiological and behavioral effects of dopamine (DA). AA reduces locomotor activity induced by dopaminergic agonist drugs. Also, AA amplifies the action of antidopaminergic drugs. Ethanol, like other drugs, produces a release of DA in the mesolimbic pathway, and at some doses, induces locomotor activity in mice. The ethanol-induced locomotor activity could be dopamine-dependent because it can be reduced by antidopaminergic drugs. In the present study, we investigated whether an acute administration of AA reduces ethanol-induced locomotor behavior. AA, at doses (0.0, 21.85, 87.5, 175, 350, and 1400 mg/kg) was injected IP …
Relationships between electrodermal activity and symptomatology in schizophrenia.
The present report studies the differences between schizophrenic responders and nonresponders within the different symptomatologic groups of the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS). The relationship between the different electrodermal activity parameters and the scores on the scales was also analyzed. The results showed that nonresponders had negative symptoms. In addition negative symptoms registered a general fall in all electrodermal-activity parameters.