Andreas Kastellakis

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It has been shown that nicotine facilitates intracranial self-stimulation (ICSS) reward and that nicotinic acetylcholine receptors (nAChRs) in the ventral tegmental area (VTA) are of primary importance for its reinforcing and dependence-producing actions. Recently, we have shown that α7 nicotinic receptors in the VTA contribute to both the acute effects of(More)
Δ(9)-tetrahydrocannabinol (Δ(9)-THC), the main psychoactive ingredient of marijuana, has led to equivocal results when tested with the intracranial self-stimulation (ICSS) procedure or the open-field test for motor activity, two behavioural models for evaluating the reward-facilitating and locomotor stimulating effects of drugs of abuse, respectively.(More)
Dopamine-somatostatin interactions were investigated in the rat striatum using in vivo microdialysis. Somatostatin-14 and somatostatin-28 (10(-4), 10(-5), 10(-6) M) were infused, and the levels of dopamine and its metabolites DOPAC and HVA were assessed using high pressure liquid chromatography with electrochemical detection. Somatostatin-14 was more(More)
Neuronal expression of Fos, the protein product of the immediate early gene c-fos has been used as a high resolution metabolic marker for mapping polysynaptic pathways in the brain. We used Fos immunohistochemistry to reveal neuronal activation following self-stimulation of the ventral pallidum. Four groups of rats were allowed to self-stimulate for 30 min(More)
The involvement of striatal somatostatin receptors (sst1, sst2 and sst4) in locomotor activity was investigated. Male Sprague–Dawley rats, 280–350 g, received in the striatum bilateral infusions of saline, somatostatin, and selective sst1, sst2, and sst4 ligands. Spontaneous locomotor activity was recorded for 60 min. The involvement of excitatory amino(More)
Bipolar disorder (BD) is a severe pathological condition with impaired reward-related processing. The present study was designed to assess the effects of two commonly used BD medications, the mood stabilizer lithium chloride (LiCl) and the atypical antipsychotic and antimanic agent aripiprazole, in an animal model of reward and motivation and on markers of(More)
Somatostatin and its receptors (sst1 and sst2) have been localized in brain nuclei implicated in motor control, such as the nucleus accumbens, ventral pallidum (VP) and substantia innominata (SI). The objective of the study is to investigate the effect of somatostatin and selective sst1 and sst2 analogs infused in the VP/SI on the locomotor activity of the(More)
This study investigated how the administration (acute and chronic) of the antidepressants citalopram and desmethylimipramine (DMI) influences somatostatin (somatotropin release inhibitory factor, SRIF) levels and SRIF receptor density (sst(1-5)) in rat brain. Animals received either of the following treatments: (1) saline for 21 days (control group), (2)(More)
Somatostatin-14 (SRIF-14) exerts anticonvulsive effects in several rat seizure models, generally attributed to sst(2) receptor activation. Whereas sst(1) immunoreactivity has been localized to both polymorphic interneurons and principal cells in the rat hippocampus, its potential role as an inhibitory autoreceptor or as a receptor involved in mediating(More)
There is increasing interest in the therapeutic potential of cannabis-based medicinal extracts in multiple sclerosis. Cognitive deficits that have been attributed to long-term heavy recreational use of cannabis are not necessarily extended to controlled pharmaceutical use of cannabis-based medicinal extracts. Available data indicate that after relatively(More)