Chromium is an essential trace element with multiple roles in the human body. It can be found in bi-, tri- and hexavalent form, and for therapeutic practice it is used mainly the trivalent chromium as picolinate salt. Frequently it is used for reducing insulin resistance and for decreasing hyperglycaemia. Chromium histidinate stimulates also the regenerative potential of cerebral tissue.
The reward system is one of the most important brain systems, with great implications in human behaviour and many substances may either stimulate or inhibit it [12].
The brain structures with the most important involvement in conditioned place preference development are nucleus accumbens, prefrontal cortex, ventral tegmental area etc. [4, 11, 15]. There are several neurotransmitters involved for conditioned place preference development. Mesolimbic dopaminergic pathways play, in the opinion of most researchers, a key role in reward and motivational processes [10, 18, 19, 21].
Other neurotransmitters, such as serotonin, glutamate, opioids, substance P are also involved in these kinds of processes [20]. Biological active metals (magnesium, zinc, calcium and others) are involved in brain reward system functions and influence conditioned place preference induced by strongly addictive substances such as morphine, heroin, cocaine and others [9, 13, 14]. There are few data referring to CrPi capacity to influence the reward system.
