Evidence that isopropylthioxanthone (ITX) is devoid of anxiolytic and sedative effect

Isopropylthioxanthone (ITX) is a well-known photo-initiator in ultraviolet light-cured inks frequently used in milk packaging materials, yoghurt, ready-to-feed infant formula, and other drinks. Traces of ITX have beenfound in milk and, as a consequence, there was considerable interest in studying the biological activity of this molecule and its potential hazard for the human health. Although the ITX genotoxic effects have been excluded 10 by the European Food Safety Authority (EFSA), the US Environmental Protection Agency (USEPA) is still examining its possible toxic potential depending on a dose–effect ratio. Little is known about the ITX activity on the function of the central nervous system and cerebral neurotransmitters. Using behavioural, biochemical, andelectrophysiological tests, the authors have found that: (1) ITX did not exert an in vivo anxiolytic or sedativeeffect when administered orally to rats; (2) ITX did not affect the binding characteristics of central and peripheral15 benzodiazepine receptors studied in vitro; and (3) ITX did not influence the ability of GABA to increase thechloride channel permeability studied by patch clamp technique in a single neuron of cultured cerebellargranule cells.