Quantitative cytochemical assay showed that single injection of delta sleep-inducing peptide increased monoamine oxidase activity (substrates: serotonin and tryptamine) in the caudate and accumbens nuclei and glutamate dehydrogenase activity in the hippocampus of stress-resistant Wistar rats chronically treated with L-DOPA. Enzyme activities in the sensorimotor cortex did not change. Delta sleep-inducing peptide had no effects on acetylcholine esterase and aminopeptidase activities in the brain of Wistar rats.
The systemic injection of haloperidol (4 wk, 0.5 mg/kg/d) caused the increase of protein concentration and content, and the activity level of aminopeptidase in the cytoplasm of the neurons of associated type (layer III). The nucleus of these cells decreased both in sizes and in the content of proteins. In the neurons of efferent-projectory type (layer V), the decrease of studied peculiarities as compared with control level was observed. Tuftsin (300 micrograms/kg/d) injection after chronic haloperidol treatment causes the restoring action on changed parameters in sensomotor cortex. In caudate nucleus, tuftsin influence caused further reduction of neuron's cytoplasmic area and significant reduction in protein content. The received results testify to the morphobiochemical heterogenity of investigated brain structures, which is displayed both in the case of haloperidol treatment and in the case of its correction by neuropeptide tuftsin. Chronic haloperidol administration to animals can develop a model of certain symptoms and syndromes of parkinsonism. Its most pronounced manifestation is an imbalance in the neuromediator systems, especially the dopaminergic one (Mettler and Crandall, 1959; Colls, 1984; Funk et al., 1986). The research was performed in conjunction with the physiologists, whose experiments have shown that after chronic haloperidol administration, changes in animal behavior are developed that are typical for bradikinesia, and the motor regimen of integration is disturbed (Popova and Kachalova, 1991; Dovedova and Povova, 1993). Regulatory drugs, especially the tetrapeptide tuftsin, seem to correct such disturbances.
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