Andreas Kastellakis

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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)
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 alpha 7 nicotinic receptors in the VTA contribute to both the acute(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)
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)
The ventral pallidum (VP) is a basal forebrain structure that is interconnected with motor and limbic structures and may be considered as an interface between motivational and effector neural signals. Results from a considerable number of studies suggest that this structure is critically involved in reward-related behavior. The VP shares reciprocal(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)
Enkephalinergic and dopaminergic mechanisms have been implicated in the electrical self-stimulation (SS) behavior. The present set of experiments investigated the role of opioid receptors within DA-innervated brain regions (nucleus accumbens and ventral tegmental area) in the ventral pallidum self-stimulation (VP-SS). Forty-one rats used in this study were(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)
In this study we examined the mode of triiodothyronine (T3) and tetraiodothyronine (T4) transport in synaptosomal preparations from cerebral hemispheres of adult rat brain. Our results show that these hormones are transported by different mechanisms: T3 uptake is a saturable process and Hofstee analysis of the data reveals two transport components--a high(More)
The involvement of striatal somatostatin receptors (sst(1), sst(2) and sst(4)) in locomotor activity was investigated. Male Sprague-Dawley rats, 280-350 g, received in the striatum bilateral infusions of saline, somatostatin, and selective sst(1), sst(2), and sst(4) ligands. Spontaneous locomotor activity was recorded for 60 min. The involvement of(More)