E. Kafetzopoulos

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Although open-field behaviour has been considered a valid and reliable index of locomotor activity in rodents, the simple measures traditionally recorded in this test do not readily allow for differentiation between compounds of the same general class, e.g. psychostimulants. The present methodology was developed to facilitate detailed and continuous(More)
Unilateral stereotaxic lesions of the subthalamic nucleus of rats with kainic acid induced a transient spontaneous ipsiversive turning which was present for several days, and which could be blocked by i.p. administration of haloperidol. After the 20th postoperative day, when no spontaneous turning activity was present, i.p. administration of apomorphine or(More)
In this study, we tested the effects of nucleus accumbens or corpus striatum lesions on the abolition of latent inhibition induced by d-amphetamine. In the latent inhibition paradigm, animals learn to ignore a repeatedly presented nonreinforced stimulus. In this paradigm, the repeated nonreinforced preexposure to a stimulus retards subsequent conditioning(More)
The neuropeptide substance P (SP) was injected into the region of the nucleus basalis magnocellularis (NBM). The influence of SP on the performance of the single trial "uphill avoidance task" was tested. The post-trial injection of 1 ng SP (in 0.5 microliter volume) led to significantly longer latencies in the uphill response. This result can be interpreted(More)
Normal rats with a unilateral ibotenic acid lesion of substantia nigra pars reticulata (SNR, n = 12) or globus pallidus (GP, n = 12) were challenged systemically with the mixed dopaminergic agonist apomorphine (0.5 and 1.5 mg/kg) and the indirect acting d-amphetamine (1.5 mg/kg). The low dose of apomorphine produced a weak contralateral rotation only in the(More)
A wide range of doses of d-amphetamine and apomorphine were injected into rats, in order to better characterize and compare dopaminergic agonist-induced behavioral effects. The study was carried out using a computerized technique for the quantification and analysis of various behavioral elements. Although both drugs increased motor activity and provided(More)
It is well known that the corpus striatum is related to the sterotyped activation induced by several psychostimulants. In this study we analyzed the effects of 6-OHDA, in comparison with those of ibotenic acid lesions, into the dorsal striatum, on the behavioural pattern induced by saline or D-amphetamine treatment. A computerized technique for recording(More)
It is well established that denervation of the dorsal striatum by its dopaminergic afferents attenuates the stereotyped response to d-amphetamine, which can be considered as an extreme form of motor activation. However, it is difficult to sustain the view that this structure serves primary motor control function because the role of dopamine in the striatum(More)
Kainic acid injections into the nucleus accumbens in rats induced severe loss of neuronal perikarya and the presence of gliosis in its vicinity, without affecting more distant areas. Spontaneous locomotor activity was elevated in the lesioned rats. After a low dose of d-amphetamine (1.5 mg/kg) no significant differences in locomotor activity were found(More)